Fruit Rot on Persimmon Caused by Neopestalotiopsis saprophytica and Neopestalotiopsis ellipsospora in Guangxi, China.

Persimmon (Diospyros kaki Thunb.) is widely cultivated in China. On October 15, 2019, about 10% of persimmon fruits showed fruit rot in the orchards of Guilin, Guangxi, China (24°45' N, 110°24' E), which could cause more than 15% of yield losses. The initial symptoms of fruit rot exhibited irregular brown to black spots (range from 2 to 4 cm in diameter), the areas surrounding the blackened spots would be soft and rotten, and three diseased fruit samples were collected from three orchards, respectively. Tissues (5×5 mm) were cut from infected margins, surface-disinfected in 75% ethanol for 10 s, 2% NaClO for 2 min, rinsed three times in sterilized distilled water, and incubated on potato dextrose agar (PDA) at 25°C under 12/12 h light/darkness for a week. Forty-one tissues yielded morphologically similar cultures, and three representative isolates LPG1-1, LPG1-2, and YSG-1 were selected from three samples for further study, respectively. Their colonies showed wavy edges, white surfaces, and dense aerial hyphae on PDA after two weeks. Conidia were fusiform, straight to slightly curved, and 4-septate; basal cells were conical, hyaline, thin, and verruculose with two or three long and hyaline apical appendages and one short apical appendage; three median cells of LPG1-1 with length 14.06 to 17.69 µm (n=100), and LPG1-2 with length 14.03 to 17.61 µm (n=100) were dark brown to olivaceous, while three median cells of YSG-1 with length 12.54 to 15.58 µm (n=100) were dark brown. The conidial sizes of LPG1-1, LPG1-2, and YSG-1 were 17.41 to 27.68 × 4.63 to 8.55 µm (n=100), 18.06 to 27.41 × 4.33 to 8.21 µm (n=100), and 16.58 to 27.73 × 4.99 to 8.39 µm (n=100), respectively. The morphological characteristics were consistent with Neopestalotiopsis spp. (Maharachchikumbura et al. 2012; Maharachchikumbura et al. 2014). Primer pairs ITS4/ITS5, BT2a/BT2b, and EF1-526F/EF-1567R were used to amplify internal transcribed spacer (ITS), beta-tubulin (TUB2), and translation elongation factor 1 alpha (TEF1-α), respectively (Shu et al., 2020). All DNA fragments were sequenced by Sangon Biotech Co., Ltd. (Shanghai, China). Sequences have been deposited in GenBank (ITS: OM349120 to OM349122, TUB2: OM688188 to OM688190, TEF1-α: OM688191 to OM688193). Based on BLASTn analysis of ITS, TUB2, and TEF1-α sequences, the LPG1-1 and LPG1-2 showed over 99% similarity to N. saprophytica, and YSG-1 showed over 99% similarity to N. ellipsospora. Phylogenetic analysis of the three isolates was performed with MEGA10 (version 10.0) based on sequences of ITS, TUB2, and TEF1-α using maximum parsimony analysis. The results revealed that LPG1-1 and LPG1-2 were clustered with N. saprophytica, and YSG-1 was clustered with N. ellipsospora. Pathogenicity tests of three isolates were conducted on 72 healthy persimmon fruits with and without wounds, and 9 fruits are for each treatment. The wound was made by a sterilized needle. Fruits were pre-processed with 75% ethanol for 10 s, 1% NaClO for 2 min and rinsed three times in sterile water. Conidial suspensions (10 µL, 106 conidia/mL in 0.1% sterile Tween 20) were inoculated on each site (4 sites/fruit). Control group was treated with 0.1% sterile Tween 20. All inoculated sites were covered with wet cotton. The inoculated fruits were placed in a plastic box to maintain humidity at 28℃. After 5 days, all wounded fruits showed fruit rot, whereas unwounded and control fruits remained asymptomatic, there were significant differences (P<0.05) in aggressiveness between N. saprophytica (average lesion diameter 13.1 mm) and N. ellipsospora (average lesion diameter 14.9 mm). Koch's postulates were fulfilled by re-isolating the causal agents from inoculated fruits. N. ellipsospora was previously reported as an endophyte in D. montana in southern India (Reddy et al. 2016). N. saprophytica could cause leaf spot of Erythropalum scandens and Magnolia sp., and fruit rot of Litsea rotundifolia in China and leaf spot of Elaeis guineensis in Malaysia (Yang et al. 2021, Ismail et al. 2017). To our knowledge, this is the first report of N. ellipsospora and N. saprophytica causing fruit rot on persimmon in the world. The results will provide a foundation for controlling fruit rot caused by pestalotioid fungi on persimmon.

First Report of Bacterial Necrosis Caused by Pantoea vagans in Mango in China.

Mango (Mangifera indica L.) is one of the most important tropical fruits in China. Bacterial black spot is one of the primary factors limiting mango production and thus leads to huge economic losses (Bie et al. 2022). In June 2020, necrotic symptoms similar to bacterial black spot was observed with incidence 30% to 65% on mango cultivar Yuwen, Jinhuang, Tainong and Guifei in Baise, Guangxi, China. Typically, the lesions began as chlorotic spots that coalesced into an irregular shape, becoming black and slightly raised, with a yellow halo. Thirteen diseased samples collected from five orchards were cut into approximately 5-mm pieces, sterilized for 10 s with 75% ethanol, soaked with 2% NaClO for 1 min, and rinsed in sterilized water three times. The samples were then homogenized and a 10-fold serial dilution was made before plating onto Lysogeny broth (LB) agar. After incubation at 28°C for 3 days, one representative colony that was beige to yellow in color, round, convex and smooth with entire margins from each orchard was selected for further study. Genomic DNA was extracted to amplify the 16S rRNA gene (Lane et al. 1991). The resulting 16S rRNA sequences were compared in GenBank using BLASTn and shared at least 99% identity with Pantoea spp.. Furthermore, six housekeeping genes fusA, gyrB, leuS, pyrG, rplB and rpoB partial sequences of five isolates were amplified and sequenced (Delétoile et al. 2009). The sequences were deposited in GenBank (16S rRNA: OL413424 to OL413246, OP225727-OP225728; leuS: OL441796, OL441798 to OL441801; fusA, gyrB, leuS, pyrG, rplB and rpoB: OP272638-OP272662). The five bacterial isolates were classified as P. vagans based on the phylogenetic tree of the concatenated sequences and sequences derived from different Pantoea reference isolates inferred by maximum-likelihood using MegaX software (Kumar et al. 2018). Biochemical tests showed the isolates were Gram-negative, oxidase negative, and hydrogen oxidase positive, and could use D-glucose, D-fructose, L-rhamnose, D-galactose and D-mannitose as a carbon resource (Bradbury, 1986). Pathogenicity tests were performed on mango cv. Yuwen. The representative isolate was inoculated by infiltration with sterile needleless syringes on healthy leaves and spraying onto slightly scratched leaves with bacterial suspensions (OD600=0.1) respectively (Kutschera, et al. 2019). A Xanthomonas citri pv. mangiferaeindicae (Xcm) suspension and sterilized water were used as positive and negative controls, respectively. Inoculated plants were kept with 90 ± 5% relative humidity and 28 ± 1°C in the greenhouse for 1 week. Black to brown necrotic symptoms were observed on all leaves inoculated by infiltration except the negative control. These were observed in plants inoculated by spraying only after 2 weeks. Bacteria re-isolated from diseased tissues were consistent with the inoculated isolates and identified as P. vagans, fulfilling Koch's postulates. To date, P. vagans have been isolated from eucalyptus with bacterial blight and dieback, and maize with brown stalk rot (Brady et al. 2009). However, to our knowledge, this is the first report of P. vagans causing bacterial necrosis on mango in China. It was also found that some of the diseased samples were coinfected with P. vagans and Xcm in our investigation. Therefore, it is necessary to further study the infection mechanisms of this pathogen.

First Report of Anthracnose of Sanhua Plum Caused by Colletotrichum aeschynomenes in Guangxi, China.

There is nearly 5,800 ha of Sanhua plum (Prunus salicina Linn) planted in Babu district in Hezhou, Guangxi, with over 67,000 tons of annual output. In August 2021, anthracnose symptoms were observed on Sanhua plum leaves in three different cultivated towns in Babu district in Hezhou, Guangxi (N23°49' - 24°48', E111°12' - 112°03'). The plant disease incidence was over 50% with approximately 20 to 30% of leaves on a plant being symptomatic. The disease outbreak occurred in the warm and damp climate (June to August) in Hezhou. Initially, small chlorotic spots developed on the leaves which gradually enlarged to larger irregular dark brown sunken lesions with yellowish halos, necrotic lesions abscised and formed holes at a later stage. In severe cases, the whole leaf withered and defoliated. Three symptomatic leaf samples were collected from three different cultivated towns in Hezhou. Margins of infected tissues were cut into 3×3 mm pieces, surface disinfected with 75% alcohol for 10 s, 2% NaOCl for 2 min followed by three washes in sterile distilled water and transferred to potato dextrose agar (PDA) plates. In total, forty-one isolates were obtained after 4 days of incubation at 25℃ on PDA, and thirty-one of them were Colletotrichum (average isolation frequency 76%). Three representative isolates (HZ18-1, HZ22-3, and HZ46-3) were selected for further study. After 7 days on PDA at 25℃, isolates had white to light grey cottony aerial mycelium on the obverse and revealed dark grey on the reverse. Conidia were hyaline, cylindroid, tapering slightly near both ends, measuring 16.3 ± 1.2 µm × 5.6 ± 0.4 µm, 16.1 ± 1.4 µm × 6.4 ± 0.7 µm, 16.2 ± 1.1 µm × 6.0 ± 0.4 µm (n=90) for HZ18-1, HZ22-3, and HZ46-3, respectively. Appressoria were brown, elliptic or fusoid, deeply lobed, measuring 10.2 ± 1.6 µm × 6.8 ± 1.0 µm, 10.7 ± 1.3 µm × 6.6 ± 0.8 µm, 9.3± 1.3 µm × 6.9 ± 0.9 µm (n=90) for HZ18-1, HZ22-3, and HZ46-3, respectively. These characteristics were consistent with the descriptions of Colletotrichum aeschynomenes B. Weir & P. R. Johnst (Weir et al. 2012). The internal transcribed spacer (ITS) region and the intergenic region and flanking regions of Apn2 and MAT1-2-1 (ApMAT) were amplified using ITS1/ITS4 and AM-F/AM-R primers, respectively (White et al. 1990; Silva et al. 2012). BLASTn analysis of the sequences showed over 99% identity with the corresponding loci from the culture collection C. aeschynomenes ICMP 17673 (ex-type). Sequences from the three isolates were deposited in GenBank (Accession Nos.: ITS, OM838335, OM838339, OM838370; ApMAT, OM816771, OM816775, OM816806). Phylogenetic maximum likelihood analysis with RAxML version 8.2.10 based on the concatenated sequences of ITS and ApMAT showed that the three isolates clustered with the ex-type specimen of C. aeschynomenes ICMP 17673. Pathogenicity was confirmed on leaves with and without wounds of 24 two-year-old Sanhua plum plants in a greenhouse. The wound was made with a sterilized toothpick. Wounded and unwounded leaves were inoculated with 20 µL of conidial suspension (106 conidia/mL) of the three isolates and control plants were inoculated with sterile distilled water (20 leaves/plant, 3 plants/treatment). All plants were covered with plastic bags to maintain high humidity. After 8 days of incubation at 25℃ with constant light, necrotic lesions were observed on inoculated leaves, whereas control plants showed no symptoms. To fulfill Koch's postulates, all fungi were successfully reisolated from symptomatic leaves. This species has been reported on Aeschynomene virginica in the United States (Weir et al. 2012), Manihot esculenta in Thailand (Sangpueak et al. 2018), Theobroma cacao (Nascimento et al. 2019) and Myrciaria dubia (Matos et al. 2020) in Brazil. To our knowledge, this is the first report of C. aeschynomenes causing Sanhua plum leaf anthracnose in China. The results will provide valuable information for management of anthracnose associated with Sanhua plum.

Identification and Observation of Infection Processes of Colletotrichum Species Associated with Pearl Plum Anthracnose in Guangxi, China.

Pearl plum (Prunus salicina Lindl.) is mainly cultivated in Tian'e County in Guangxi Province, southern China. Anthracnose is a devastating disease on pearl plum, causing extensive leaf blight. Diseased leaves were sampled from 21 orchards in Tian'e County. Isolates were first screened for ones resembling Colletotrichum, and 21 representative isolates were selected for sequencing of portions of the ribosomal internal transcribed spacer (ITS), the intergenic region of apn2 and MAT1-2-1 genes (ApMAT), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), chitin synthase (CHS-1), and ß-tubulin 2 (TUB2). Based on colony, conidial, and appressorial morphology and sequence analyses, the Colletotrichum isolates associated with pearl plum anthracnose were identified as four species: Colletotrichum fructicola (16 isolates), C. gloeosporioides (3 isolates), C. cigarro (1 isolate), and C. siamense (1 isolate). The results of pathogenicity tests showed that isolates of all four species were pathogenic to wounded leaves of pearl plum seedlings. In this study, we microscopically observed the infection processes of isolates of these four species on attached pearl plum leaves. For C. cigarro and C. siamense, the entire infection processes took 120 h; for C. fructicola and C. gloeosporioides, it only took 72 h. This is the first report of C. fructicola and C. cigarro causing anthracnose on pearl plum worldwide, and also the first report of C. siamense causing anthracnose on pearl plum in China.

Philodendron bipinnatifidum anthracnose Caused by Colletotrichum karsti and C. endophytica in Guangxi, China.

Philodendron bipinnatifidum Schott ex Endl (Araceae) is native to South America. It was introduced in Guangdong around the 1980s, and then gradually promoted for use as a landscape ornamental in South China (You et al. 2013). Previous studies showed that an extract of P. bipinnatifidum displayed antinociceptive and anti-inflammatory activities (Scapinello et al. 2019). In August 2019 and June 2020, leaf spot disease was observed on P. bipinnatifidum leaves in Qingxiushan Park, Nanning, Guangxi province, China, with approximately 80% disease incidence. Symptoms began as small brown spots that extended into large, irregular, dark brown, necrotic, sunken lesions. The leaves eventually became yellow and then withered and died. The symptomatic leaves were sampled from three different places in the park. Leaf pieces (5× 5 mm) of three samples were cut from the junction of diseased and healthy leaf tissue, disinfected in 75% (v/v) alcohol for 10 sec, 2% (v/v) sodium hypochlorite for 1 min, and then rinsed three times in sterile distilled water before pieces were incubated on potato dextrose agar (PDA) at 25°C for 7 days. Eighty-one Colletotrichum isolates were obtained, with an 88% isolation rate, and three of these (GBZ7-1, GBZ7-3 and GBZ8-2) were selected for intensive study. After 7 days, the colonies on PDA showed white-to-gray aerial mycelium. Conidia (n=90) were elliptical, single-celled, hyaline, straight, 14.61 ± 0.08 µm × 6.84 ± 0.04 µm (C. karsti), and 15.15 ± 0.11 µm ×5.04 ± 0.04 µm (C. endophytica). Appressoria (n=90) were melanized, subglobose, irregular, 9.57 ± 0.17 µm × 7.18 ± 0.10 µm (C. karsti), and 7.36 ± 0.18 µm × 5.52 ± 0.13 µm (C. endophytica). To confirm morphological identification, the rDNA internal transcribed spacer region (ITS), actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), ß-tubulin 2 (TUB2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes (Weir et al. 2012) were amplified and sequenced (GenBank accessions Nos. ITS (MZ962373 ~ MZ962375), ACT (OK040200 ~ OK040202), CAL (OK040205 ~ OK040207), CHS-1 (OK040210 ~ OK040212), TUB2 (OK040220 ~ OK040222) and GAPDH (OK040215 ~ OK040217) of GBZ7-1, GBZ7-3 and GBZ8-2 respectively). Phylogenetic analysis was done using RAXML (Version 2.0) based on sequences of multiple loci (ITS, ACT, CAL, CHS-1, TUB2 and GAPDH). Isolates GBZ7-1 and GBZ7-3 were identified as C. karsti and GBZ8-2 as C. endophytica. Pathogenicity tests were performed with the three isolates on 45 asymptomatic attached leaves of nine one-year-old plants (three plants per isolate). Every leaf was punctured at three points using a sterile needle and inoculated with 10 µl of conidial suspension (106spores/ml) on each wound. Wounded leaves treated with sterilized water under the same conditions served as controls. The experiment was repeated three times. All plants were sprayed with water and covered with plastic bags to maintain high humidity. Sunken necrotic lesions were observed on all inoculated leaves after 15 days at 28 °C, whereas no symptoms were observed on the control leaves. C. karsti and C. endophytica were consistently re-isolated from the inoculated leaves which was confirmed by morphology and sequencing, fulfilling Koch's postulates. C. siamense was previously reported as a pathogen on P. bipinnatifidum in China (Ning et al. 2021). To our knowledge, this is the first report of leaf spot caused by C. karsti and C. endophytica on P. bipinnatifidum worldwide. This research may accelerate the development of future epidemiological studies and management strategies for anthracnose caused by C. karsti and C. endophytica on P. bipinnatifidum.

First Report of Leaf Blight Caused by Fusarium pernambucanum and Fusarium sulawesiense on Plum in Sichuan, China.

Plum (Prunus salicina Lindl.) is widely cultivated for its rich nutrients and flavor in China. In August 2020, leaf blight symptoms were observed on plum in Meishan, Sichuan, China (N29°24', E104°30'). Irregular brown spots initially appeared on the edge or tip of the leaf, then extended to larger taupe lesions that were surrounded by a chlorotic halo. In the late stage, grey-brown blighted tissue covered the entire leaf causing leaves to wither, curl and abscise. The leaves with blight were collected from three different towns in Meishan where the disease incidence was found on 15-30% of plum plants. The margin of diseased leaves was cut into small pieces (3×3 mm), surface disinfected with 75% ethanol solution for 10 s, 2% NaOCl for 1 min, and rinsed in sterile distilled water three times. Tissue pieces were plated on potato dextrose agar (PDA) and incubated at 25°C. Forty-nine morphologically similar colonies were observed on PDA plates after 3-5 days and three of these (TEY9-1, TEY12-1, TEY15A-1) were selected for intensive study. The colonies produced abundant whitish to yellowish aerial mycelium after 7 days incubation at 25°C in the dark. Macroconidia on carnation leaf agar (CLA) were falcate, hyaline, straight to slightly curved, smooth to slightly rough with 3 to 6 septa, the apical cell was blunt or hooked, and the basal cell was barely notched, 31.6 ± 2.4 µm × 4.7 ± 0.4 µm, 28.9 ± 3.0 µm × 4.5 ± 0.5 µm, 32.5 ± 3.4 µm × 4.5 ± 0.5 for TEY9-1, TEY12-1, TEY15A-1, respectively. Microconidia were hyaline, fusoid or ovoid, nonseptate or one-septate, 14.4 ± 3.9 µm × 4.3 ± 0.6 µm, 13.0 ± 3.0 µm × 4.0 ± 0.4 µm, 11.0 ± 2.4 µm × 3.7 ± 0.5 for TEY9-1, TEY12-1, TEY15A-1, respectively. Genomic DNA was extracted from 7-day-old aerial mycelia of these isolates. The internal transcribed spacer (ITS), translation elongation factor (TEF1), calmodulin (CAM) and partial RNA polymerase second largest subunit (RPB2) were amplified using primers ITS4/ITS1, EF1/EF2, CL1/CL2A, and 5f2/7cr, respectively (White et al. 1990; O'Donnell et al. 2000, 2010). Sequences were deposited in GenBank (ITS: OK315638-OK315640; TEF1: OK338756-OK338758; CAM: OK338759-OK338761; RPB2: OK338762-OK338764). A maximum Likelihood (ML) phylogenetic tree was constructed with RAxML version 8.2.10 based on the concatenated sequences (ITS, TEF1, CAM, RPB2). According to morphology and phylogenetic analysis, TEY9-1 and TEY15A-1 were identified as Fusarium pernambucanum, and TEY12-1 was identified as Fusarium sulawesiense. Pathogenicity tests were conducted on young healthy leaves of 12 two-year-old plum plants in a 28°C greenhouse in Nanning, Guangxi, China. The epidermis of tested leaves was slightly scratched with sterile toothpick-tips forming a 3-mm-diameter cross-shaped wound, followed by inoculation with a 10 µl conidial suspension (106 spores /ml in 0.1% sterile Tween 20). Control leaves were wounded in the same way and treated with 0.1% sterile Tween 20. Plants were covered with polythene bags to maintain high humidity for 5 days. Inoculated leaves showed light brown to dark brown lesions, whereas control leaves were symptomless. Both species were re-isolated from symptomatic leaves, completing Koch's postulates. To our knowledge, this is the first report of F. pernambucanum and F. sulawesiense causing leaf blight on plum trees in China. These results will provide valuable information for prevention and management of leaf blight on plum trees.

First Report of Leaf Spot Caused by Colletotrichum citricola on Cavendish bananas in China.

Cavendish banana (Musa spp. AAA group) is an important tropical and subtropical fruit with significant economic value. It is widely planted in Guangxi, Yunnan, Hainan, Fujian and Guangdong provinces in China. In November 2020, leaf spots were observed on nearly 80% of the plants growing in three Cavendish banana plantations in Chongzuo, Guangxi, China. The symptoms on Cavendish banana leaves initially appeared as small black necrosis spots, which gradually expanded and connected, eventually covered the entire leaf. Three diseased leaves from three plantations were collected, sectioned into small pieces (5 ×5 mm), surface sterilized (10 s in 75% ethanol, followed by 1 min in 1% sodium hypochlorite and rinsed three times in sterile water) and placed on potato dextrose agar (PDA) at 28℃ for 5 days for pathogen isolation. The fungal colonies were white, cottony, while the reverse sides were white, concentric circles with yellowish-brown discoloration in 7-day cultures. The conidia were hyaline, aseptate, cylindrical, oval, measuring 10.3 to 17.71 µm (mean 14.06 ± 1.45 µm; n = 200) in length and 4.48 to 9.57 µm (mean 7.46 ± 0.69 µm; n = 200) in width. Three representative isolates (DX1-5, LZ4-5, and FS1-3) were obtained by monosporic isolation. The partial internal transcribed spacer (ITS) regions, actin (ACT), chitin synthase (CHS-1), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), and ß-tubulin (TUB2) were amplified from genomic DNA for the three isolates (Weir et al. 2012). The sequences of the amplified fragments were deposited in GenBank (accessions OL361844 to OL361858, for GAPDH, CAL, ACT, CHS-1, and TUB2 of isolate DX1-5, LZ4-5 and FS1-3; OL305066 to OL305068 for ITS) and showed over 99% identities with the corresponding sequences of C. citricola. A neighbor-joining phylogenetic tree based on the above six genes of type or ex-type specimens of Colletotrichum (Fu et al. 2019) was constructed with MEGA 5.2 using the concatenation of multiple sequences (Kumar et al. 2016). All three isolates clustered together with the type culture of C. citricola (CBS 134228, CBS 134229, CBS 134230) with 82% bootstrap support in the phylogenetic tree. According to the molecular and morphological characteristics, all three isolates were identified as C. citricola. Pathogenicity tests were conducted on one-month-old primary hardened tissue culture plantlets. Tender, healthy leaves were gently scratched with a sterile needle, and each wound site was inoculated with sterile cotton impregnated with conidial suspension (106 spores/ml) for each isolate. Wounded leaves were treated with sterile cotton impregnated with conidial suspension of C. fructicola as positive controls and sterile water as negative controls. Each isolate was inoculated with three tissue culture plantlets, six inoculated sites on each plantlet, the same as controls. All inoculated tissue culture plantlets were covered with plastic bags to maintain high humidity and placed in a 28℃ growth chamber with constant light. Black necrotic lesions were clearly observed on the inoculated leaves and the positive controls after 7 days, whereas no symptoms appeared on the negative control leaves. The fungus was re-isolated from inoculated leaves, and these isolates matched the morphological and molecular characteristics of the original isolates confirming Koch's postulates. To our knowledge, this is the first report of leaf spot caused by C. citricola on Cavendish banana worldwide.

Genome Resource of a Hypervirulent Strain C9-3 of Xanthomonas oryzae pv. oryzae Causing Bacterial Blight of Rice.

Xanthomonas oryzae pv. oryzae is the causal agent of bacterial blight, one of the most devastating diseases of rice. Here, a hypervirulent strain, C9-3, defeating Xa1, Xa10, xa13, and Xa23 resistance genes, was used to extract genomic DNA for single molecule real-time (SMRT) sequencing. After assembly, the genome consists of a single-circular chromosome with the size of 4,924,298 bp with G+C content of 63.7% and contains 4,715 genes. Annotation and analysis of the TALE genes using a suite of applications named AnnoTALE suggested that 17 transcription activator-like effectors, including 15 typical TALEs and 2 iTALEs/truncTALEs, were encoded in the genome. The approach and genome resource will contribute to the discovery of new virulence effectors and understanding on rice-X. oryzae pv. oryzae interactions.

Litchi anthracnose caused by Colletotrichum karstii in Guangxi, China.

Litchi (Litchi chinensis Sonn.), a native fruit tree from southern China, has been planted in many subtropical and tropical countries for its fruit which are considered delicious and of medicinal value (Anderson et al. 2013). Anthracnose, one of the most important diseases on litchi, can cause flower drop, fruit drop, and fruit rot. Infected leaves form dark brown spots which turn to reddish brown with gray-white edges. Infected fruits formed dark brown spots which developed eventually to entire black rotted fruits. On both tissues, small dots of acervuli appeared with high humidity (Lai et al. 2004). On 20 April 2019, two leaf spots samples of litchi from different plants were collected from a 2 ha litchi orchard in Xintang Town (N 22.38˚, E 108.61˚), Qinzhou City, Guangxi province. The incidence of leaf spots in the orchard was above 20%. Each sample was cut into multiple pieces targeting zone between symptomatic and healthy plant tissues, disinfected with 75% ethanol for 10 s and 1% sodium hypochlorite (NaClO) for 1 min, and then washed three times with sterilized distilled water. The sterilized leaf tissues were placed on potato dextrose agar (PDA) and incubated at 28°C in darkness for one week. The growing hyphae from each sample was transferred to fresh PDA. The pieces from each leaf yielded a similar fungal morphotype over 75% of the time, and a representative one from each leaf was retained and called LZ1-1 and LZ3-1. The resulting colonies were incubated on the PDA for 7 days with gray to white aerial tufted hyphae, and abundant colorless to pale orange conidia in center of colony. The conidia were smooth, apex obtuse, base truncate, straight, cylindrical, and the contents remained granular. The conidial size of LZ1-1 was 10.6 to 21.4 × 4.5 to 9.1 µm (n=100) and that of LZ3-1 was 12.7 to 16.7 × 5.5 to 8.0 µm (n=100). Appressoria of LZ1-1 (6.9 to 14.9 × 6.0 to 11.1 µm) (n=100) and LZ3-1 (6.5 to 15.4 × 5.4 to 11.4 µm) (n=100) were pale to medium brown, ovoid to bullet-shaped, not nodose, and smooth-walled to undulate. DNA was extracted from two isolates, followed by PCR amplification and sequencing using primers for the rDNA internal transcribed spacer (ITS), actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and ß-tubulin (TUB2) (Damm et al. 2012). The resulting sequences were deposited in GenBank (ITS: MW494453 and MW494454, ACT: MW495034 and MW495035, CAL: MW495036 and MW495037, CHS-1: MW495038 and MW495039, GAPDH: MW495040 and MW495041, TUB2: MW495042 and MW495043). The concatenated sequences comprised of six genomic regions of LZ1-1, LZ3-1 and other sequences of Colletotrichum obtained from GenBank were used to construct a Neighbor-Joining (NJ) tree with 1000 bootstrap replicates using MEGA4 (Tamura et al. 2007). The results revealed both LZ1-1 and LZ3-1 were clustered with type strain of C. karstii with high bootstrap value. The pathogenicity of the two isolates was determined by inoculating on leaves of 1-year-old litchi saplings in the greenhouse. Slight scratches were made on the surface of healthy leaves and 10 µL of spore suspension (106 conidia/mL) in 0.1% Tween 20 were inoculated onto each wounded spot. The blank control groups were inoculated with 10 µL 0.1% Tween 20. Each isolate was inoculated onto at least 27 leaves of three saplings, with each leaf wounded at spots. The inoculated saplings were placed in a greenhouse (12 h/12 h light/dark, 25 ± 2°C), and humidity maintained by covering plastic bags. The leaves inoculated with spore suspension showed reddish-brown spots after one week, while no symptoms were observed in the control. Each fungal isolate was consistently reisolated from inoculated leaves, thus fulfilling Koch's postulates. It was reported that members of the C. acutatum species complex and the C. gloeosporioides species complex could cause anthracnose on litchi (Ling et al. 2019), including C. gloeosporioides, C. siamense, C. fioriniae, and C. simmondsii (Ling et al. 2019; 2020). To our knowledge, this is the first report of anthracnose on litchi in China caused by C. karstii, a member of the C. boninense species complex. This study expands the understanding of the pathogen of anthracnose on litchi which can lead to improved management and control.

First Report of Anthracnose of Papaya (Carica papaya L.) Caused by Colletotrichum siamense in China.

Papaya (Carica papaya L.) is a rosaceous plant widely grown in China, which is economically important. Anthracnose caused by Colletotrichum sp. is an important postharvest disease, which severely affects the quality of papaya fruits (Liu et al., 2019). During April 2020, some mature papaya fruits with typical anthracnose symptoms were observed in Fusui, Nanning, Guangxi, China with an average of 30% disease incidence (DI) and over 60% DI in some orchards. Initial symptoms of these papayas appeared as watery lesions, which turned dark brown, sunken, with a conidial mass appearing on the lesions under humid and warm conditions. The disease severity varied among fruits, with some showing tiny light brown spots, and some ripe fruits presenting brownish, rounded, necrotic and depressed lesions over part of their surface. Samples from two papaya plantations (107.54°E, 22.38°N) were collected, and brought to the laboratory. Symptomatic diseased tissues were cut into 5 × 5 mm pieces, surface sterilized with 2% (v/v) sodium hypochlorite for 1 minute, and rinsed three times with sterilized water. The pieces were then placed on potato dextrose agar (PDA). After incubation at 25°C in the dark for one week, colonies with uniform morphology were obtained. The aerial mycelium on PDA was white on top side, and concentric rings of salmon acervuli on the underside. A gelatinous layer of spores was observed on part of PDA plates after 7 days at 28°C. The conidia were elliptical, aseptate and hyaline (Zhang et al., 2020). The length and width of 60 conidia were measured for each of the two representative isolates, MG2-1 and MG3-1, and these averaged 13.10 × 5.11 µm and 14.45 × 5.95 µm. DNA was extracted from mycelia of these two isolates with the DNA secure Plant Kit (TIANGEN, Biotech, China). The internal transcribed spacer (ITS), partial actin (ACT), calmodulin (CAL), chitin synthase (CHS), ß-tubulin 2 (TUB2) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) regions were amplified by PCR and sequenced. The sequences were deposited into GenBank with accessions MT904003, MT904004, and MT898650 to MT898659. BLASTN analyses against the GenBank database showed that they all had over 99% identity to the type strain of Colletotrichum siamense isolate ICMP 18642 (GenBank accession numbers JX010278, GQ856775, JX009709, GQ856730, JX010410, JX010019) (Weir et al., 2012). A phylogenetic tree based on the combined ITS, ACT, CAL, CHS, TUB2 and GAPDH sequences using the Neighbor-joining algorithm also showed that the isolates were C. siamense. Pathogenicity tests were conducted on 24 mature, healthy and surface-sterilized papaya fruits. On 12 papaya fruits, three well separated wounded sites were made for inoculation, and for each wounded site, six adjacent pinhole wounds were made in a 5-mm-diameter circular area using a sterilized needle. A 10 µl aliquot of 1 × 106 conidia/ml suspension of each of the isolates (MG2-1 and MG3-1) was inoculated into each wound. For each isolate, there were six replicate fruits. The control fruits were inoculated with sterile distilled water. The same inoculation was applied to 12 non-wound papaya fruits. Fruits were then placed in boxes which were first washed with 75% alcohol and lined with autoclaved filter paper moistened with sterilized distilled water to maintain high humidity. The boxes were then sealed and incubated at 28°C. After 10 days, all the inoculated fruits showed symptoms, while the fruits that were mock inoculated were without symptoms. Koch's postulates were fulfilled by re-isolation of C. siamense from diseased fruits. To our knowledge, this is the first report of C. siamense causing anthracnose of papaya in China. This finding will enable better control of anthracnose disease caused by C. siamense on papaya.

First Report of Colletotrichum siamense Causing Leaf Spot on Alocasia macrorrhiza in China.

Alocasia macrorrhiza (L.) Schott, known as Alocasia is found in the Araceae, and is widely planted in southern China for its ornamental and medicinal value. This plant has a wide range of pharmacological effects, and has potential anti-tumor activity (Lei et al. 2013). In July of 2019, leaf spots were observed on A. macrorrhiza in the Xixiangtang Area, Nanning, Guangxi, China. Disease symptoms began with water-soaked yellow-green spots and progressed to form brown, round or oval lesions with yellow halos. Under severe conditions, spots merged into larger irregular lesions. More than 60% of the plants in a 0.5 ha field showed disease symptoms. Symptomatic leaves were collected and cut into small pieces (3×3 mm). Leaf pieces from the margin of the necrotic tissue were surface sterilized in 75% alcohol for 10 s, followed by 2% sodium hypochlorite solution for 2 min, then rinsed three times in sterile distilled water. Tissues were plated on potato dextrose agar (PDA) and incubated at 28°C for 5 days in the dark. Among over 30 isolates, most shared a similar morphology, the isolation rate of these was 86.7% and three of these (GY1-1A, GY1-1B, and GY1-1C) were chosen for single-spore purification and used for fungal morphological characterization and identification. White feathery aerial mycelia with olivaceous gray mycelia below were observed in 7-day cultures. After 14 days, orange conidia were observed. Conidia were hyaline, guttulate, smooth, one-celled, and cylindrical, averaged 13.79 µm × 5.26 µm, 13.89 µm × 5.33 µm and 13.92 µm × 5.42 µm for GY1-1A, GY1-1B and GY1-1C, respectively. Appressoria were mostly irregular in outline, deeply lobed or lightly lobed, gray brown to dark brown, conidial appressoria were 7.93 to 8.74 µm × 5.26 to 5.42 µm, mycelial appressoria were 7.15 to 10.11 µm × 5.60 to 7.44 µm. These morphological characteristics were similar to the C. siamense as previously described (Weir et al. 2012). The partial internal transcribed spacer (ITS) regions, actin (ACT), chitin synthase (CHS-1), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), ß-tubulin (TUB2), and the intergenic region of apn2 and MAT1-2-1 (ApMAT) were amplified from genomic DNA for the three isolates using primers ITS4/ITS1 (White et al. 1990), ACT-512F/ACT-783R, CHS-79F/CHS-354R, GDF1/GDR1, CL1C/CL2C, Bt2a/Bt2b (Weir et al. 2012), and AM-F/AM-R (Silva et al. 2012) and sequenced. All sequences showed over 99% identity with C. siamense and were deposited in GenBank (ITS, MW040179-MW040181; ACT, MW049220-MW049222; CHS-1, MW049229-MW049231; GAPDH, MW049232-MW049234; CAL, MW049226-MW049228; TUB, MW049235-MW049237; ApMAT, MW049223-MW049225). Maximum Likelihood (ML) phylogenetic tree was constructed with MEGA 5 using the concatenation of multiple sequences (ACT, CHS-1, GAPDH, ITS, TUB2, CAL). According to the phylogenetic tree, all three isolates were found with C. siamense with 95% bootstrap support. To confirm pathogenicity, three sets (three plants per set) of healthy leaves were slightly scratched with autoclaved toothpicks at each of eight locations. Each inoculation location was a cross (2 mm length) and inoculation location was at least 3 cm apart. Ten µl of conidial suspension (106 conidia /ml in 0.1% sterile Tween 20) was applied to the inoculation areas. A control group was mock inoculated with 0.1% sterile Tween 20. Plants were covered with plastic bags to maintain a high humidity environment and placed in a 28°C growth chamber with constant light for 7 days. Inoculated leaves showed yellowish brown spots (0.4 × 0.65 cm), but no symptoms were observed in the control group. The fungus was reisolated from inoculated leaves, and these isolates matched the molecular and morphological characteristics of the original isolates confirming Koch's postulates. Reported hosts of this pathogen include Coffea arabica, Carica papaya, Melilotus indicus and Litchi chinensis (Weir et al. 2012; Qin et al. 2017; Ling et al. 2019) and so on. To our knowledge, this is the first report of C. siamense causing leaf spot on A. macrorrhiza in China. The identification of this pathogen provides a foundation for the management of leaf spot on this medicinal plant.

Fusarium species associated with leaf spots of mango in China.

Mango is one of the important commercially cultivated fruit crops in southern China. In continuing research on foliar diseases of mango in south of China during 2016-2017, leaf spot disease was common at all mango orchards investigated. The purpose of this study was to investigate Fusarium species associated with leaf spots of mango in the main production areas of China, and to identify them to species. Twenty-two Fusarium isolates were obtained from diseased leaves from seven provinces (Fujian, Guangdong, Guangxi, Guizhou, Hainan, Sichuan and Yunnan), and then identified using morphological characteristics and phylogenetic analysis. These isolates were from seven species: F. concentricum, F. hainanense, F. mangiferae, F. pernambucanum, F. proliferatum, F. sulawesiense, and F. verticillioides. We found all 22 isolates to be capable of causing leaf spot symptoms on artificially wounded leaves. To our knowledge, this is the first report of F. concentricum, F. hainanense, F. mangiferae, F. pernambucanum, F. sulawesiense and F. verticillioides associated with leaf spots on mango in China, and the first for F. concentricum, F. hainanense, F. pernambucanum, F. sulawesiense from mango worldwide. This is one of the few reports on Fusarium species as potential causal agents of mango leaf spots.

First report of Colletotrichum fructicola causing anthracnose on Pouteria campechiana in China.

Pouteria campechiana (Kunth) Baehni (=Lucuma nervosa A. DC.) is a fruit crop planted in southern China (Gao et al. 2019). It is originally from Central America, and also grown there commercially as well as in some American states (Fadzilah et al. 2018). In March 2019, a leaf spot disease was found on P. campechiana in Baoshan, Yunnan, China. Field surveys were done in a 0.06 ha orchard in Yunnan Province. Leaf spots were found on 90% of six-year-old plants in this field and were observed in other planting areas. The symptoms initially appeared as small, round, brown spots. As the disease developed, the center of the lesions was sunken with a dark brown border (Fig. 1). Under severe conditions, some spots were joined into larger irregular spots, and even whole leaves died. The disease severity of different plants varied, and some leaves showed only a few brown spots while others showed many spots. Small fragments of diseased tissues (3×3 mm) were disinfected in 75% ethanol for 10 s, 1% NaClO for 1 min, and rinsed three times in sterilized water. Then, tissues were placed onto potato dextrose agar (PDA), and incubated at 25°C in the dark for 5 days. Fungal isolates with similar morphology were consistently recovered from diseased tissues. The 25 colonies were initially cottony, pale white to pale gray on the upper side and greyish-green with black zonation on the underside of plates. Conidia were single-celled and hyaline, aseptate, straight, and cylindrical, with rounded ends (Fig. 1B). The length and width of 200 conidia were measured for two representative isolates, DHG-1 and DHG-2, and these averaged 14.48 × 5.59 µm and 14.92 × 5.57 µm. Appressoria were ovoid, sometimes clavate, brown, averaged 7.47 × 5.86 µm and 7.25 × 5.85 µm (n=30). Brown and globose ascocarp were observed on the leaves of Pouteria campechiana. Asci were unitunicate, thin-walled, 6-8 spored, clavate, averaged 51.53×13.01 µm and 50.21 × 13.32 µm (n=30). Ascospores were hyaline, one-celled, slightly curved to curved with obtuse to slightly rounded ends, averaged 14.64×5.97 µm and 15.19 × 6.23 µm (n=30). These two isolates were selected for molecular identification. DNA was extracted from mycelia with the DNA secure Plant Kit (TIANGEN, Biotech, China). For further molecular identification, the internal transcribed spacer (ITS), partial actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-tubulin (TUB2), and the Apn2-Mat1-2 intergenic spacer and partial mating type (Mat1-2) gene (ApMat) genes of the strains (DHG-1, DHG-2) were amplified using the primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CL1C/CL2C, CHS-79F/CHS-345R, GDF1/GDR1, T1/Bt-2b, and AM-F/AM-R (Weir et al. 2012; Silva et al. 2012), respectively.The sequences were obtained and compared with GenBank and they all showed over 99% identity to the type strain of Colletotrichum fructicola ICMP 18581 (Accession nos. JX010165, JX010033, JQ807838, FJ907426, JX010405, JX009866, and FJ917508) (Weir et al. 2012). A phylogenetic tree based on the combined ITS, ACT, CAL, CHS-1, TUB2, GAPDH and ApMat sequences using the Neighbor-joining algorithm revealed that the isolates were C. fructicola (Fig. 2). The sequences were deposited into GenBank with accession MN955541, MN955542, and MN966581 to MN966592. Pathogenicity tests were conducted on eighteen healthy and tender leaves of six 1-year-old P. campechiana plants in a greenhouse. The experiment was repeated twice. The length and width of the inoculated leaves were between 8-13 cm × 2.5-3.6 cm. The epidermis of each tested leaf was lightly scratched in six separate areas with a sterilized needle. Each isolate was inoculated onto at least three wounded leaves by placing 20 µL of a conidial suspension (106 conidia/mL) on the wound sites. Control leaves were also wounded and inoculated with distilled water. All the plants were then sprayed with distilled water and covered with plastic bags. After 10 days, initial symptoms appeared as circular and deep yellow spots. After a few more days, the spots became brown, enlarged to up to 4.0 mm which was similar to symptoms observed in the field, whereas controls remained symptomless. Koch's postulates were fulfilled by re-isolation of C. fructicola from diseased leaves, and identification confirmed by sequencing. Colletotrichum fructicola has been associated with anthracnose on mango, apple, pear and cassava (Oliveira et al. 2018). To our knowledge, this is the first report of C. fructicola associated with anthracnose of P. campechiana worldwide. These results will provide crucial information for future epidemiological studies and for management of this disease.

First Report of Leaf Spot Caused by Colletotrichum fructicola and C. siamense on Zizyphus mauritiana in Guangxi, China.

Zizyphus mauritiana Lam. is an important tropical fruit tree and has significant economic value. It is widely planted in Hainan, Guangdong, Guangxi and Fujian provinces in China (Yang et al. 2017). In March 2019, leaf spot was observed on leaves of Z. mauritiana at Bagui fields in Nanning, Guangxi, China, with incidence exceeding 50%. Symptomatic leaves developed a yellow to tan-brown sunken lesion and finally abscised. To isolate the pathogen causing the symptoms, small pieces (5 × 5 mm) of infected leaves were surface sterilized by exposure to 75% ethanol for 10 sec, 1% sodium hypochlorite for 1 min and rinsed three times in sterile water. Fifty pieces were isolated, surface sterilized, and pieces were plated onto potato dextrose agar (PDA) and grown at 28°C for 7 days. The isolation rate of Colletotrichum species was 100%. Three representative isolates (DQZ3-1, DQZ3-2 and DQZ3-3) were selected for further study. Mycelia were greyish-white for all three isolates, with isolate DQZ3-1 also appearing dark green in the center of the colony. Conidia were elliptical, aseptate and hyaline, with sizes of 13.4 ± 0.12 µm × 5.7 ± 0.1 µm, 14.8 ± 0.1 µm × 5.8 ± 0.1 µm and 15.1 ± 0.1 µm × 5.5 ± 0.1 µm for DQZ3-1, DQZ3-2 and DQZ3-3, respectively. Genomic DNA was extracted using the DNAsecure Plant Kit [Tiangen Biotech (Beijing) Co., Ltd] and the internal transcribed spacer (ITS), partial actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), beta-tubulin (TUB2), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were sequenced (Weir et al. 2012). Phylogenetic analysis of the three isolates was performed with MEGA-X (Version 10.0) based on sequences of multiple loci (ITS, ACT, CAL, CHS-1, TUB2 and GAPDH) using Maximum Likelihood analysis. Isolate DQZ3-1 was identified as C. fructicola, and the other two isolates, DQZ3-2 and DQZ3-3, were identified as C. siamense (accessions MT039396 to MT039410, for ACT, CAL, CHS-1, GAPDH and TUB2 of DQZ3-1, DQZ3-2 and DQZ3-3; MT041651 to MT041653 for ITS of DQZ3-1, DQZ3-2 and DQZ3-3). Pathogenicity tests were conducted on 1-year-old plants. Young, healthy leaves were artificially wounded by gently scratching with a sterile needle and 10 µl droplets of conidial suspension (106 spores/ml) applied per wound site for each isolate. Some wounded leaves were inoculated with 10 µl droplets of water as controls. Each isolate was inoculated onto three plants, with 15 leaves at least for each plant, same as controls. All inoculated plants were sprayed with water and covered with plastic bags to maintain high humidity. Symptomatic lesions were observed on the inoculated leaves after 7 days at 28°C, whereas no symptoms were observed on the control leaves. To fulfill Koch's postulates, fungi were re-isolated from 50 symptomatic leaf pieces and fungi re-isolated from each leaf piece were morphologically identical to the inoculated isolates, for a 100% isolation frequency. To our knowledge, this is the first report of leaf spot caused by C. fructicola and C. siamense on Z. mauritiana worldwide. This research may accelerate the development of future epidemiological studies and management strategies for anthracnose caused by C. fructicola and C. siamense on Z. mauritiana.

Identification and Characterization of Pestalotioid Fungi Causing Leaf Spots on Mango in Southern China.

Mango is an economically important fruit crop in southern China. However, leaf spots restrict the development of mango trees, reducing the yield and production. Pestalotioid fungi are one of the major agents causing leaf spots on mango. During 2016 and 2017, 21 isolates of pestalotioid fungi associated with leaf spots on mango leaves were collected from five provinces in southern China: Guangxi, Hainan, Yunnan, Guangdong, and Fujian. All 21 isolates were subjected to morphological characterization and DNA sequence analysis. The morphological data were combined with analyses of concatenated sequences of the ITS (internal transcribed spacer), TEF 1-α (translation elongation factor), and TUB2 (ß-tubulin) for higher resolution of the species identity of these isolates. The results showed that these isolates belong to Neopestalotiopsis clavispora, Pestalotiopsis adusta, P. anacardiacearum, P. asiatica, P. photinicola, P. saprophyta, P. trachicarpicola, and Pseudopestalotiopsis ampullacea. Pathogenicity test results showed that all these species could cause symptoms. On detached mango leaves (cv. Tainong), early foliar symptoms on leaves were small yellow-to-brown lesions. Later, these spots expanded with uneven borders, turned white to gray, and coalesced to form larger gray patches. To our knowledge, this is the first description of N. clavispora, P. adusta, P. asiatica, P. photinicola, P. saprophyta, P. trachicarpicola, or Ps. ampullacea as causal agents for leaf spots on mango worldwide.

In vitro antifungal activity of dimethyl trisulfide against Colletotrichum gloeosporioides from mango.

Colletotrichum gloeosporioides, one of the main agents of mango anthracnose, causes latent infections in unripe mango, and leads to huge economic losses during storage and transport. Dimethyl trisulfide (DMTS), one of the main volatile compounds produced by some microorganisms or plants, has shown antifungal activity against some phytopathogens in previous studies, but its effects on C. gloeosporioides and mechanisms of action have not been well characterized. In fumigation trials of conidia and mycelia of C. gloeosporioides for 2, 4, 6, 8, or 10 h, at a concentration of 100 µL/L of air space in vitro, DMTS caused serious damage to the integrity of plasma membranes, which significantly reduced the survival rate of spores, and resulted in abnormal hyphal morphology. Moreover, DMTS caused deterioration of subcellular structures of conidia and mycelia, such as cell walls, plasma membranes, Golgi bodies, and mitochondria, and contributed to leakage of protoplasm, thus promoting vacuole formation. In addition, to better understand the molecular mechanisms of the antifungal activity, the global gene expression profiles of isolate C. gloeosporioides TD3 treated in vitro with DMTS at a concentration of 100 µL/L of air for 0 h (Control), 1 h, or 3 h were investigated by RNA sequencing (RNA-seq), and over 62 Gb clean reads were generated from nine samples. Similar expressional patterns for nine differentially expressed genes (DEGs) in both RNA-seq and qRT-PCR assays showed the reliability of the RNA-seq data. In comparison to the non-treated control groups, we found DMTS suppressed expression of ß-1, 3-D-glucan, chitin, sterol biosynthesis-related genes, and membrane protein-related genes. These genes related to the formation of fungal cell walls and plasma membranes might be associated with the toxicity of DMTS against C. gloeosporioides. This is the first study demonstrating antifungal activity of DMTS against C. gloeosporioides on mango by direct damage of conidia and hyphae, thus providing a novel tool for postharvest control of mango anthracnose.

Colletotrichum species associated with mango in southern China.

Mango (Mangifera indica L.) is an economically significant fruit crop in provinces of southern China including Hainan, Yunnan, Sichuan, Guizhou, Guangdong and Fujian. The objective of this study was to examine the diversity of Colletotrichum species infecting mango cultivars in major growing areas in China, using morphological and molecular techniques together with pathogenicity tests on detached leaves and fruits. Over 200 Colletotrichum isolates were obtained across all mango orchards investigated, and 128 of them were selected for sequencing and analyses of actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the internal transcribed spacer (ITS) region, ß-tubulin (TUB2) genomic regions. Our results showed that the most common fungal isolates associated with mango in southern China involved 13 species: Colletotrichum asianum, C. cliviicola, C. cordylinicola, C. endophytica, C. fructicola, C. gigasporum, C. gloeosporioides, C. karstii, C. liaoningense, C. musae, C. scovillei, C. siamense and C. tropicale. The dominant species were C. asianum and C. siamense each accounting for 30%, and C. fructicola for 25%. Only C. asianum, C. fructicola, C. scovillei and C. siamense have previously been reported on mango, while the other nine Colletotrichum species listed above were first reports associated with mango in China. From this study, five Colletotrichum species, namely C. cordylinicola, C. endophytica, C. gigasporum, C. liaoningense and C. musae were the first report on mango worldwide. Pathogenicity tests revealed that all 13 species caused symptoms on artificially wounded mango fruit and leaves (cv. Tainong). There was no obvious relationship between aggressiveness and the geographic origin of the isolates. These findings will help in mango disease management and future disease resistance breeding.

A new species of Procontarinia (Diptera: Cecidomyiidae) damaging fruit of mango, Mangifera indica (Anacardiaceae), in China.

Larvae of a previously unknown species of gall midge were found feeding on young fruit of mango, Mangifera indica (Anacardiaceae), in Guangxi Autonomous Region in southern China, causing severe damage to the crop. The new species is named Procontarinia fructiculi Jiao, Wang, Bu Kolesik, its morphology is described, the basic biology is given, and the Cytochrome Oxidase subunit I (COI) mitochondrial gene segment is sequenced and compared to other congeners. Procontarinia contains now 16 described species, each feeding on mango. All but three species cause variously shaped galls on leaves, while P. mangiferae (Felt) malforms inflorescence and young leaves, and two species feed on fruit - P. frugivora Gagné causing deep lesions and P. fructiculi sp. nov. tunnel-like holes. Of the two fruit-feeding species, P. frugivora is confined to the Philippines while the new species has thus far been recorded only from southern China.

Draft Genome Sequence of an Isolate of Colletotrichum fructicola, a Causal Agent of Mango Anthracnose.

Here, we present a draft genome sequence of isolate 15060 of Colletotrichum fructicola, a causal agent of mango anthracnose. The final assembly consists of 1,048 scaffolds totaling 56,493,063 bp (G+C content, 53.38%) and 15,180 predicted genes.