First Report of White Mucus Disease Caused by Fuligo gyrosa on Agrocybe chaxingu in China.

Agrocybe chaxingu is an edible and medicinal mushroom widely cultivated in China (Liu et al. 2021). Agrocybe chaxingu is extremely well-liked for the unique flavor and nutritional value. In May 2021, a serious white mucus disease was observed in the farms of A. chaxingu in the Ganxian district of Ganzhou City, Jiangxi Province, China, with an approximate disease incidence of 20%. In the years of 2022 and 2023, the same white mucus disease on A. chaxingu was observed in the farms in Nanchang City, Jiujiang City and Guangchang County, Jiangxi Province, China. The disease generally occurs on the media, stipe or pileus of A. chaxingu under condition of high humidity. The plasmodial slime molds migrated from the surface of culture media (78% hardwood sawdust, 15% wheat bran, 5% tea seed shell, 1% lime, and 1% gypsum) to the base of fruiting bodies, stipes and finally to pilei, showing as moist, sticky, and white reticulated structures. The infected fruiting bodies of A. chaxingu were completely covered by reticulated plasmodia, displaying a white or pale-yellow color. This resulted in the growth cessation, wilting and eventual death of fruiting body. Microscopic observation found that the plasmodia of slime mold enveloped the hyphae of A. chaxingu, resulting in the fragmentation of the hyphae. The disease can spread quickly, resulting in a 30% reduction in production. Slime mold cultures were isolated by transferring diseased fruiting bodies of A. chaxingu onto oat-agar medium (2% agar and 1% oatmeal) at 25 ℃. The isolates can be obtained after being subcultured for two to three generations. Purified plasmodia were placed on the semi-defined medium (1% tryptone, 1% glucose, 0.15% yeast extract, chick embryo extract and a balanced salt solution) to confirm the absence of bacteria (Daniel et al. 1964) and thus obtained the pure culture. Specimen of the voucher has been deposited in the Institute of Agricultural Applied Microbiology, Jiangxi Academy of Agricultural Sciences as number IAAM-W0002. The vegetative plasmodia have a large and well-developed scalloped structure that were white or milky white in colour. The white plasmodium became opaque pale yellow when exposed to light before fruiting. The veins merged and thickened. Fruiting bodies can be formed on the lid or side of the Petri dish under light condition. The fruiting bodies formed papillae with irregular shape, and then the color changed from translucent yellow to greyish black. Spores were usually spherical or subglobose, free, greyish brown in mass, purplish brown, 7-12 µm in diameter under light microscopy. These morphological characteristics were found to be consistent with those of Fuligo gyrosa (Synonym: Physarum gyrosum) (Kim et al. 2009; Shi et al. 2005; Jahn 1902). The identity of the isolates was further confirmed by sequence analysis of the 18S ribosomal RNA gene with primer SMNUR101/NS4 (Rusk et al. 1995; White et al. 1990). Using BLASTn searches, the sequence of 18S rRNA gene (GenBank accession number OR186216) matched the sequence of F. gyrosa (GenBank accession number LC744593) with the identity of 99.91% and coverage of 97%. A phylogenetic tree based on the 18S rRNA gene also demonstrated that the slime mold clustered with F. gyrosa. Over ten isolates have been obtained from the diseased A. chaxingu samples in different factories and identified as F. gyrosa. To test the pathogenicity of F. gyrosa, five healthy young fruiting bodies (three to five days of primordium) of A. chaxingu cultivated in mushroom-growing room were gently inoculated by a 12 mm diameter oat-agar medium with plasmodia at 24 ± 2 ℃ and then were kept with relative humidity of 90%-95%. Five fruiting bodies inoculated with a 12 mm oat-agar medium served as controls. After 5 days, white mucus characteristics and three fifths of death symptoms were observed on the fruiting bodies inoculated with the plasmodia, while the controls remained asymptomatic. The slime mold on the inoculated fruiting bodies was morphologically identical to F. gyrosa that was observed on the initial diseased fruiting bodies. It was also observed the envelopment A. chaxingu hyphae by the plasmodia of slime mold and fragmentation of the hyphae, and the fragmentation was not observed in the controls. Reisolations were prepared from the inoculated fruiting bodies and confirmed to be F. gyrosa based on morphological characteristics and 18S rRNA sequence, thus fulfilling Koch's postulates. Fuligo gyrosa has been reported to cause severe disease in oriental melon in Korea (Kim et al. 2009). This is the first report of F. gyrosa causing white mucus disease in cultivated A. chaxingu. The findings will provide important information on prevention and control of the disease, and be helpful for the development of A. chaxingu industry.

First Report of Pseudopestalotiopsis ixorae Causing Leaf Spot of Photinia × fraseri in China.

Photinia × fraseri is a well-known ornamental shrub in southern China. In December 2021, we observed leaf spots that were circular to irregular, gray with dark red margins and violet brown with brownish violet edges on the leaves of Photinia × fraseri shrubs in the scenic area of Shenlongtan (28°46'10″N, 115°42'93″E), Jiangxi Province, China. Almost 15% of the leaves in the 1300 m2 Photinia × fraseri planting area were symptomatic. Thirty symptomatic leaves were randomly collected from different plants, and sectioned into 5-mm2 pieces, which were surface-sterilized using 1% NaOCl for 30 s. After rinsing thrice in sterile distilled water and drying, the pieces were transferred onto potato dextrose agar (PDA) and incubated at 28 ℃ for 5-7 days. A total of sixteen morphologically similar isolates were obtained. After incubation on PDA for 20 days, the fungi had irregular edges, were white to pale brown, and had spare aerial mycelium on the surface with irregularly distributed black, gregarious conidiomata. Conidia were fusoid, subcylindrical, straight to slightly curved, 4-septated, slightly constricted at the septa, and 23 to 36 × 6 to 10 µm (mean: 27.6 × 7.7 µm). The morphological characteristics were consistent with the features of Pseudopestalotiopsis species (Maharachchikumbura et al. 2014). The genomic DNA of two representative isolates (JFRL032 and JFRL033) was extracted for further identification. The internal transcribed spacer (ITS) region, translation elongation factor 1-ɑ (tef1-ɑ) and ß-tubulin (tub2) genes were amplified and sequenced using primers ITS5/ITS4, EF1-526F/EF1-1567R, and Bt2A/Bt2B, respectively (Maharachchikumbura et al. 2012). The sequences of the two representative isolates were 100% identical to each other. These nucleotide sequences were deposited in GenBank with accession numbers, ON342794 and ON342795 (ITS); ON375851 and ON375852 (tef1-ɑ); ON375853 and ON375854 (tub2). BLASTn searches of the obtained sequences revealed 99%-100% to ITS (MG816316, 478/478 nucleotides), tef1-ɑ (MG816336, 924/926 nucleotides), tub2 (MG816326, 441/442 nucleotides) sequences of the ex-type strain of Pseudopestalotiopsis ixorae (NTUCC17-001.1). Phylogenetic analysis was conducted using the concatenation of multiple sequences (ITS, tef1-ɑ and tub2) with the Maximum likelihood statistics in PhyloSuite v1.2.2 (Zhang et al.2020). The phylogenetic tree showed the two isolates clustered with P. ixorae in a clade with 100% bootstrap support. The isolates were identified as P. ixorae based on morphological and molecular data. To confirm pathogenicity, eight healthy leaves of 3-year-old Photinia × fraseri were surface sterilized, scratched with a pair of sterilized tweezers, and ten µl of conidial suspension (106 conidia/ml) was sprayed on the injured leaves and the control was sprayed with sterile distilled water. Then, All plants were potted in a climate chamber at 25℃ and 85% relative humidity. After 3 days, leaf spot symptoms similar to those described above were observed on inoculated leaves, while the non-inoculated leaves remained symptomless. The pathogen was reisolated from the inoculated leaves to fulfill Koch's postulates and confirmed as P. ixorae by morphological and molecular analysis. It has been reported that P. ixorae can infect the Ixora plant (Tsai et al., 2018). To the best of our knowledge, this is the first report of P. ixorae causing leaf spot on Photinia × fraseri in China. The study provides valuable information for identifying and controlling the leaf spot on Photinia × fraseri.

First Report of Postharvest Fruit Rot on Gannan Navel Orange Caused by Diaporthe unshiuensis in Jiangxi Province, China.

The Gannan navel orange (Citrus sinensis Osbeck cv. Newhall) is one of the most widely planted citrus fruit cultivars in Ganzhou City, Jiangxi Province, China. A Gannan navel orange was harvested from an orchard in Yudu County, Ganzhou City, Jiangxi Province, China, in October 2022 (25.95N, 115.41E). Approximately 5% of the fruit rotted after being stored at room temperature for about two weeks.Infected fruits appear brown and rotted with slightly indented edges. Initially symptoms of infected fruits was small circular, light brown, which the rot expands, slightly water-stained halo circle with slightly indented edges. The surface of 10 infected fruits was sterilized with 75% ethanol, and the lesion edge was cut into 5-mm-diameter pieces, and the pieces were then placed on potato dextrose agar (PDA) and incubated at 25°C for five days. A total of eight morphologically similar isolates were obtained. PDA results showed dense white and fluffy aerial mycelia in the center of colonies with sparser edges. Two types of conidia were produced; the alpha conidia were hyaline, ellipsoidal or clavate, and aseptate, with 2 oil drops, 4.8 to 7.5 × 2.1 to 2.7 µm (n=30). The beta conidia were hyaline, aseptate, filiform, smooth, straight to sinuous, 16.9 to 27.5 × 1.3 to 1.6 µm (n=30). These isolates exhibit morphological characteristics similar to those of the Diaporthe genus. Genomic DNA of two representative isolates (JFRL-03-1130 and JFRL-03-1131) was extracted for further confirmation. The internal transcribed spacer (ITS) region, beta-tubulin (TUB), calmodulin (CAL), partial translation elongation factor 1-alpha (TEF1-α), and histone H3 (HIS3) genes were amplified and sequenced using primers ITS1/ITS4, Bt2a/Bt2b, CAL228F/CAL737R, EF1-728F/EF1-986R, and CYLH3F/H3-1b, respectively (Udayanga et al. 2015). These nucleotide sequences were deposited into the GenBank database with accession numbers OQ691637-OQ691638 (ITS), OQ701022-OQ701023 (TUB), OQ701016-OQ701017 (CAL), OQ701018-OQ701019 (TEF1-α) and OQ701020-OQ701021 (HIS3). The maximum likelihood analyses were performed for the combined ITS, TEF1-a, TUB, HIS3, and CAL data set using Phylosuite V1.2.2 (Zhang et al. 2020). The phylogenetic tree showed that the two isolates clustered with D. unshiuensis in a clade with 100% bootstrap support. Therefore, the fungus was identified as D. unshiuensis based on morphological and molecular characteristics. To evaluate pathogenicity, a sterile scalpel was used to wound 10 surface-sterilized fruits, and a 5-mm-diameter mycelial plug of the isolate JFRL 03-1130, cultured on PDA at 25℃ for 7-days, was put on the wound. Another set of 10 fruits was similarly inoculated with sterile agar plugs as controls. The fruits were cultured at 25°C and 85% relative humidity, and the test was repeated twice. These fruits inoculated with D. unshiuensis showed similar rot symptoms after 10 days, while the control group remained symptomless. In order to prove Koch's postulates, the pathogen was re-isolated from the inoculated fruits and confirmed as D. unshiuensis by molecular techniques, but never from the control fruits. Diaporthe unshiuensis has been reported as an endophyte associated with citrus and a pathogen that causes melanose disease in citrus (Chaisiri et al. 2020; Huang et al. 2015). However, to the best of our knowledge, this is the first reported case of D. unshiuensis causing postharvest fruit rot on Citrus sinensis. In the past, D. sojae has also been reported causing postharvest fruit brown rot disease on Citrus sinensis in China (Xiao, et al. 2023); Therefore, managers should pay more attention to postharvest fruit rot disease caused by Diaporthe species and implement storage strategies to control and reduce losses.

First Report of Leaf Blotch Caused by Phyllosticta capitalensis on Daphne odora in China.

Daphne odora Thunb. an evergreen shrub with scented flowers, is used for ornamental purposes but it also has medicinal benefits (Otsuki, et al. 2020). In August 2021, leaf blotch symptoms were observed on roughly 20% of leaves of D. odora var. marginata plants in Fenghuangzhou Citizen Park, Nanchang city (28°41'48.12″ N, 115°52'40.47″ E), Jiangxi Province, China. Brown lesions first appeared on the edges of leaves, which eventually dried and died (Fig. 1A). For fungal isolation, 12 symptomatic leaves were randomly collected, the edges between diseased area and healthy area were cut into small pieces (4×4 mm), surface-sterilized by dipping in 70% ethanol for 10 s and 1% sodium hypochlorite for 30 s, and then rinsed three times with sterile distilled water. Leaf pieces were then plated on potato dextrose agar (PDA) and incubated at 28 ℃ for 3-4 days. A total of 10 isolates were recovered from the diseased leaves. The pure colonies of all fungal isolates had similar characteristics, and three isolates were randomly selected (JFRL 03-249, JFRL 03-250 and JFRL 03-251) for further study. Colonies of this fungus were gray and uneven, with a granular surface, and irregular white edges, finally turning black on PDA (Fig. 1B, C). Pycnidia were black, globose and 54-222 µm in diameter (Fig. 1D). Conidia were hyaline, single-celled, and nearly elliptical, which ranged from 7 to 13 × 5 to 7 µm (n=40) (Fig. 1E). These morphological characteristics were consistent with those described for the fungus Phyllosticta spp. (Wikee et al. 2013a). To confirm the fungal identity, the internal transcribed spacer (ITS) region, actin (ACT), translation elongation factor 1-alpha (TEF1-a), glyceradehyde-3-phosphate dehydrogenase (GPD) and RNA polymerase II second largest subunit (RPB2) genes were amplified using primers ITS5/ITS4, ACT-512F/ACT-783R, EF-728F/EF2, Gpd1-LM/Gpd2-LM and RPB2-5F2 /fRPB2-7cR, respectively (Wikee et al. 2013b). The sequences of the selected isolates were 100% identical. Hence, sequences of one representative isolate JFRL 03-250 were deposited in GenBank (OP854673, ITS; OP867004, ACT; OP867007, TEF1-a; OP867010, GPD; and OQ559562, RPB2). BLAST search analysis in GenBank showed 100% similarity with those of P. capitalensis (GenBank accession nos. ITS, MH183391; ACT, KY855662; TEF1-a, KM816635; GPD, OM640050 and RPB2, KY855820). From a phylogenetic perspective, a maximum likelihood phylogenetic tree was constructed by using IQtree V1.5.6 based on multiple sequences (ITS, ACT, TEF1-a, GPD and RPB2) (Nguyen et al. 2015), and the cluster analysis resulted the representative isolate JFRL 03-250 within a clade comprising Phyllosticta capitalensis (Fig. 2). Based on morphological and molecular characters, the isolate was identified as P. capitalensis. To confirm pathogenicity and fulfill Koch's postulates, 6 healthy potted plants were inoculated with 1× 106 conidia/ml suspension of isolate JFRL 03-250 by spraying on the leaves, whereas 6 plants were sprayed with sterile distilled water to serve as control. All potted plants were incubated at 28°C, 80% relative humidity and 12-h light/12-h dark alternating conditions in a climate cabinet. After 15 days, similar symptoms were observed in the inoculated leaves as in the field (Fig. 1F), whereas control leaves remained asymptomatic (Fig. 1G) and P. capitalensis was successfully re-isolated from the symptomatic leaves. Previously, P. capitalensis has been reported to cause brown leaf spot disease of various host plants around the world (Wikee et al. 2013b). However, to our knowledge, this is the first report of brown leaf spot caused by P. capitalensis on D. odora in China.

First Report of Brown Spot of Dekopon Fruit Caused by Cladosporium tenuissimum in China.

Dekopon citrus (Citrus reticulata Shiranui) is a three-way hybrid (Citrus unshiu Marcov. × C. sinensis Osbeck × C. reticulata Blanco) developed in Japan in 1972. This citrus is popular in China due to its sweet and tender taste (Lim 2012). In November of 2021, a brown spot disease on Dekopon fruits with about 20% disease incidence was observed in an orchard of the Institute of Citrus Research in Ganzhou, Jiangxi Province, China. Initially, the symptoms appeared as slightly sunken deep red to purple spots on the fruit surface, with the disease progression, lesions became brown to brown-black large necrotic regions covered with a fluffy layer of gray spores. Infected fruits were surface sterilized with 70% ethanol for 30 sec and rinsed three times with sterile distilled water. Diseased tissues from the edge of lesions were cut into small segments, placed onto potato dextrose agar and incubated at 25℃ for 7 days. Ten single-spore isolates were obtained in total. Fungal colonies were olive green to dark green, velvet-like in texture and sporulated abundantly, surrounded by grayish-white hyphae. Conidiophores were subcylindrical, straight, septate, solitary or in clusters of two to three, and ranged in size from 65 to 550 × 3.8 to 6.3 µm (x ̅= 261.7 ± 60.5 × 5.2 ± 0.4 µm, n=50). Ramoconidia were cylindrical，aseptate, and 10 to 22 × 2.8 to 4.5 µm (x ̅= 15.5 ± 1.4 × 4.0 ± 0.9 µm, n=50). Conidia were lemon-shaped to oval-shaped, smooth-walled, and 1.8 to 5.0 × 1.4 to 2.5 µm (x ̅= 3.9 ± 0.4 × 2.2 ± 0.2 µm, n=50). The morphological characteristics of the pathogen were consistent with those of Cladosporium tenuissimum Cooke (Li et al. 2021). For further identification, DNA was extracted from two representative isolates. The internal transcribed spacer (ITS) region, translation elongation factor (EF1-α), and actin (ACT) were amplified by using primers ITS1/ITS4, EF1-728F/EF1-986R, and ACT-512F/ACT-783R (Bensch et al. 2012), respectively. ITS (OM232067, OM232068), EF1-α (OM256525, OM256526) and ACT (OM256529, OM256530) sequences were deposited in GenBank. Multi-gene (combined data set of ITS, EF1-α and ACT) phylogenetic analysis was conducted using the Maximum Likelihood method (Nguyen et al. 2015). Based on the morphological characteristics and the molecular data, two fungal isolates were identified as C. tenuissimum. To evaluate pathogenicity, fifteen fruits were surface sterilized with 1% NaClO solution for 30 sec, rinsed twice with sterile distilled water and dried. Dekopon fruits (n=10) were wounded with a sterile needle and inoculated with a 10 µL drop of conidial suspension (1 × 106 conidia/mL) of isolate GZCJ-1, followed by incubation at 25℃ and 80% relative humidity. The controls (n=5) were treated with sterile water and maintained under the same conditions. Five days after inoculation, small brown sunken spots were observed on the wounded and inoculated fruits. After 7 days, lesions were coated by a layer of brown conidia that were similar to those described above, whereas control remained symptomless. Pathogenicity test was repeated twice. Cladosporium tenuissimum was consistently re-isolated from inoculated fruits and confirmed by morphological and molecular data, fulfilling the Koch's postulates. To our knowledge, this is the first report of C. tenuissimum causing the brown spot of dekopon fruit in China and perhaps the world. The disease may become the potential risk for fruit production, making fruits unfit for marketing purposes, and the appropriate management actions will be necessary.

First Report of Brown Rot Caused by Phytophthora nicotianae on Navel Orange Fruit in China.

Navel orange (Citrus sinensis Osbeck cv. Newhall) is widely planted in southern China. From September to November 2021, severe outbreaks of Phytophthora brown rot were observed on navel orange fruit in three local orchards in Ganzhou City (28.80N, 115.53E), Jiangxi Province, China, with a disease incidence of 25 to 35%. Symptomatic fruit was mostly observed 1-m from the ground. Initial symptoms on infected fruit were circular, pale-brown to brown, water-soaked, slightly sunken lesions, covered with sparse white mycelia-like growth. As the disease progressed, the lesions turned dark brown and enlarged on the fruit surface. Three to four infected fruits were randomly collected from each orchard, placed in transparent plastic bags and immediately brought back to the laboratory for isolations. Infected fruits were surface-disinfested with 70% ethanol for 60 sec, and rinsed three times with sterile water. Symptomatic tissues from the margin between necrotic and healthy tissues were cut into 5 mm × 5 mm pieces, placed onto potato dextrose agar and incubated at 28°C for 5 days. Nine isolates were obtained. Colonies of three isolates (JFRL 03-16, 03-18, 03-19) in 10-day-old 20% V8 juice agar consisted of abundant, white, cottony aerial mycelia. Hyphal swellings and coenocytic mycelium were observed. Sporangia were ovoid, ellipsoid to spherical, papillate, and ranged in size from 17.2 to 60.1 µm × 15.8 to 48.6 µm (x ̅=46.2 ± 5.5 × 32.4 ± 4.8 µm, n=50). Chlamydospores were spherical, suborbicular, and ranged from 17.8 to 45.9 µm diam (x ̅=30.5 ± 3.5 µm, n=50). Oospores were not observed in pure cultures. These morphological characteristics were consistent with those of P. nicotianae (LaMondia et al. 2014). Genomic DNA was extracted from a representative isolate, JFRL 03-18, using the NuClean Plant Genomic DNA kit (CWBIO, China). The internal transcribed spacer (ITS) region, ras-related protein ypt1 (YPT), ß-tubulin (TUB) gene were amplified by Polymerase Chain Reaction using primers ITS1/ITS4 (White et al. 1990), Yph1F/Yph2R (Schena et al. 2008), and TUBUF2/TUBUR1 (Kroon et al. 2004), respectively. All sequences were deposited in GenBank (Accession Nos. ON231777 for ITS, ON246910 for YPT, ON246908 for TUB). BLASTN homology search for these nucleotide sequences showed 100% identical to the ITS (MH341621), YPT (MK058408), TUB (MH760160) sequences of P. nicotianae. Sequences of twelve Phytophthora species and Pythium ostracodes were downloaded from GenBank. The phylogenetic tree of combined ITS, YPT, TUB sequences showed that the isolate JFRL 03-18 clustered with P. nicotianae. To complete Koch's postulates, zoospore suspensions were prepared from the cultures grown on 10-day-old V8 juice agar of isolates (JFRL 03-16, 03-18, 03-19). Pathogenicity tests were performed on healthy and surface-disinfested navel orange fruit. Nine fruits were gently wounded with a needle, inoculated with 10 µl zoospore suspension (104 zoospores/ml) of three isolates separately, and three fruit treated with sterilized water as controls. All fruit were incubated at 25℃ with 80% relative humidity and the test was repeated three times. After 7 days of incubation, the fruit inoculated with P. nicotianae showed similar brown rot symptoms and the control fruit remained symptomless. The pathogen was re-isolated from all inoculated fruits and confirmed as P. nicotianae by morphological and molecular analysis. Phytophthora nicotianae was previously reported on Hamlin sweet orange (Citrus sinensis (L.) Osbeck) fruit causing Phytophthora brown rot in Florida (Graham and Timmer 1995; Hao et al. 2018). To our knowledge, this is the first report of P. nicotianae causing Phytophthora brown rot of navel orange fruit in China. Based on the severity of this disease, local growers should develop and implement integrated disease management strategies for control.

Effects of revegetation on the composition and diversity of bacterial and fungal communities of sandification land soil, in Southern China.

This study aimed to research the effects of forest (Pinus elliottii, slash pine) and shrub (Vitex trifolia) plantation on the soil microbial community in sandification land by using the Illumina Miseq sequencing of 16S rRNA and ITS rRNA genes and combined with the soil properties analysis to explore the driving factors. Finally, the results showed that the dominant bacterial phyla were Chloroflexi, Actinobacteria, Proteobacteria, and Acidobacteria; the shrub and forest plantation significantly increasing the proportion of Acidobacteria, while decreasing the proportion of Proteobacteria. For the fungal community, forest plantation was significantly changing the community structure at the phylum level that shifted from Ascomycota to Basidiomycota, and the ectomycorrhizal fungi take the most abundant with genus Rhizopogon predominant. The soil bacterial Chao1 and Shannon indices were significantly increased after revegetation, while the soil fungal Shannon diversity in the forest land that significantly correlated with soil total organic carbon and C/N was lower than that in the sandy and shrub land (p < 0.05). Besides, the bacterial and fungal communities were significantly affected by soil water content among all analyzed soil properties. Our results suggest that the revegetation significantly increasing the soil bacterial diversity that correlated with soil water content, total organic carbon, and available phosphorus, but there was no significant change in community structure. In contrast, slash pine plantation changes the fungal community structure and diversity dramatically. This change and possible succession of fungal community with stand age increasing may lead to the fragility of the plantation, which deserves continuous attention.

Phytochemical Study of Stem and Leaf of Clausena lansium.

Clausena lansium Lour. Skeels (Rutaceae) is widely distributed in South China and has historically been used as a traditional medicine in local healthcare systems. Although the characteristic components (carbazole alkaloids and coumarins) of C. lansium have been found to possess a wide variety of biological activities, little attention has been paid toward the other components of this plant. In the current study, phytochemical analysis of isolates from a water-soluble stem and leaf extract of C. lansium led to the identification of 12 compounds, including five aromatic glycosides, four sesquiterpene glycosides, two dihydrofuranocoumarin glycosides, and one adenosine. All compounds were isolated for the first time from the genus Clausena, including a new aromatic glycoside (1), a new dihydrofuranocoumarin glycoside (6), and two new sesquiterpene glycosides (8 and 9). The phytochemical structures of the isolates were elucidated using spectroscopic analyses including NMR and MS. The existence of these compounds demonstrates the taxonomic significance of C. lansium in the genus Clausena and suggests that some glycosides from this plant probably play a role in the anticancer activity of C. lansium to some extent.

Synthesis and structure-activity relationship of theasapogenol galactosides against Magnaporthe oryzae.

Camellia oleifera is expected to provide alternative aglycone to synthesize some saponins similar to that from Schima superba with inhibitory activity against Magnaporthe oryzae. Eight theasapogenol galactosides were synthesized via protection of adjacent hydroxyl groups by a benzylidene for regioselective glycosylation in the multi-hydroxyl sapogenin. Water soluble galactose chain connected far from liposoluble end was a key group in inhibiting the growth of M. oryzea unless theasapogenol was modified by two galactosyl groups or by one galactosyl group and one benzylidene group. The amphoteric characteristics of saponin such as saccharide group number, distance between bipolar groups play an important role in inhibiting mycelium growth of M. oryzae.

Diversity of crude oil-degrading bacteria and alkane hydroxylase (alkB) genes from the Qinghai-Tibet Plateau.

The aim of this study was to survey the response of the microbial community to crude oil and the diversity of alkane hydroxylase (alkB) genes in soil samples from the Qinghai-Tibet Plateau (QTP). The enrichment cultures and clone libraries were used. Finally, 53 isolates and 94 alkB sequences were obtained from 10 pristine soil samples after enrichment at 10 °C with crude oil as sole carbon source. The isolates fell into the phyla Proteobacteria, Actinobacteria, and Bacteroidetes, with the dominance of Pseudomonas and Acinetobacter. The composition of degraders was different from polar habitats where Acinetobacter sp. is not a predominant responder of alkane degradative microbial communities. Phylogenetic analysis showed that the alkB genes from isolates and enrichment communities formed eight clusters and mainly related with alkB genes of Pseudomonas, Rhodococcus, and Acinetobacter. The alkB gene diversity in the QTP was lower than marine environments and polar soil samples. In particular, a total of 10 isolates exhibiting vigorous growth with crude oil could detect no crude oil degradation-related gene sequences, such as alkB, P450, almA, ndoB, and xylE genes. The Shannon-Wiener index of the alkB clone libraries from the QTP ranged from 1.00 to 2.24 which is similar with polar pristine soil samples but lower than that of contaminated soils. These results indicated that the Pseudomonas, Acinetobacter, and Rhodococcus genera are the candidate for in situ bioremediation, and the environment of QTP may be still relatively uncontaminated by crude oil.

A new species of Dictyochaeta (Sordariomycetes, Chaetosphaeriales, Chaetosphaeriaceae) from freshwater habitats in China.

Background: Freshwater fungi refer to the fungi that depend on the freshwater habitats for the whole life cycle or part of their life cycle. In this context, a new aquatic hyphomycete was isolated from decaying wood in a freshwater habitat in Jiangxi Province, China. New information: Dictyochaetajiangxiensis sp. nov., a new aquatic hyphomycete, is characterised by its unbranched, septate, base-fertile conidiophores with multisepta and single phialide at the apex, brown, sterile seta, monophialidic, subcylindrical conidiogenous cells narrowing below the funnel-shaped collarette, hyaline, unicellular, thin-walled, smooth, guttulate, falcate to subclavate conidia narrowly rounded at both ends with hair-like appendages. Phylogenetically, the new species Dictyochaetajiangxiensis clustered together with Dictyochaetabrevis MFLU 19-0216 in a well-supported clade, but formed a separate branch. In order to better define the taxonomic status of the new species, a phylogenetic tree of most closely-related taxa in Chaetosphaeriaceae was established, based on multi-locus sequences (ITS and LSU). The novel species is described and illustrated. Newly-generated molecular data of Dictyochaetajiangxiensis is also provided.

Chemical components from the stems and leaves of Clausena lansium (Lour.) Skeels and their potential herbicidal effects.

BACKGROUND: Clausena lansium (Lour.) Skeels, belonging to the genus Clausena of the family Rutaceae, has a wide range of medical and agricultural activities. Previous studies on agricultural activities have shown that C. lansium extracts and some components have obvious herbicidal activities. In order to study systematically herbicidal activity of this plant, we studied the herbicidal effect of ethyl acetate (EtOAc) extract from the stems and leaves of this plant and further isolated the active compounds. RESULTS: The EtOAc extract inhibited the growth of roots and shoots of Echinochloa crus-galli (L.) Beauv., and the inhibitory effect of the EtOAc extract on roots were stronger than those on shoots with half maximal inhibitory concentration (IC50 ) values of 420.45 and 585.05 mg L-1 , respectively. Fifteen compounds were subsequently isolated and identified from the stems and leaves of C. lansium, including nine O-monoterpenoid furanocoumarins and six cinnamamides. Our results showed that most compounds exhibited varying degrees of herbicidal activities to E. crus-galli. Among them, compounds 3, 8, and 13-15 showed the best inhibitory activities on the growth of E. crus-galli roots, with inhibition rate values ranging from 70% to 83% at a concentration of 300 mg L-1 . Compounds 1 and 2 are two new compounds, and their structures were established as 5-O-monoterpenoid furanocoumarin and 8-O-monoterpenoid furanocoumarin, and named as claulansicoumarin-A and -B, respectively. CONCLUSION: The EtOAc extract and pure compounds showed noticeable herbicidal activities against E. crus-galli and indicated a great potential for these natural compounds to be developed as a herbicide. © 2020 Society of Chemical Industry.

First record of the rare genus Typhrasa (Psathyrellaceae, Agaricales) from China with description of two new species.

Typhrasa is a rare genus that comprises two species and that has previously been reported only from Europe and North America. The present study expands the geographical scope of the genus by describing two new species - T. polycystis and T. rugocephala - from subtropical China. The new species are supported by morphological characteristics and phylogenetic analyses (ITS, LSU and tef-1α). The new species have very similar morphological characteristics and are 98% similar in their ITS region. However, T. rugocephala has two types of long gills at the same time, rarely fusiform pleurocystidia with rostrum. Detailed descriptions, colour photos, illustrations and a key to related species are presented in this paper.

Kinetic characterization and structural modeling of an NADP+-dependent succinic semialdehyde dehydrogenase from Anabaena sp. PCC7120.

Succinic semialdehyde dehydrogenases (SSADH) of cyanobacteria played a pivotal role in completing the cyanobacterial tricarboxylic acid cycle. The structural information of cofactor preference and catalysis for SSADH from cyanobacteria is currently available. However, the detailed kinetics of SSADH from cyanobacteria were not characterized yet. In this study, an all3556 gene encoding SSADH from Anabaena sp. PCC7120 (ApSSADH) was amplified and the recombinant ApSSADH was purified homogenously. Kinetic analysis showed that ApSSADH was an NADP+-dependent SSADH, which utilized NADP+ and succinic semialdehyde (SSA) as its preferred substrates and the activity of ApSSADH was inhibited by its substrate of SSA. At the same time, the Ser157 residue was found to function as the determinant of cofactor preference. Further study demonstrated that activity and substrate inhibition of ApSSADH would be greatly reduced by the mutation of the residues at the active site. Bioinformatic analysis indicated that those residues were highly conserved throughout the SSADHs. To our knowledge this is the first report exploring the detailed kinetics of SSADH from cyanobacteria.

Simultaneous interpenetrating silicone hydrogel based on radical/addition polymerization for extended release of ocular therapeutics.

Hydrogels with interpenetrating network (IPN) can overcome thermodynamic incompatibility and obtain transparent materials with limited phase separation. In this report, hydroxyl-grafting polysiloxane (HPSO) was synthesized and transparent silicone hydrogels with interpenetrating network were simultaneously prepared based on radical polymerization of methacrylic monomer of 3-methacryloxypropyl tris(trimethylsiloxy)silane/N,N-dimethylacrylamide and addition polymerization of HPSO/isophorone diisocyanate. The silicone hydrogels were characterized by dehydration kinetics, tensile tester, light transmittance, ion permeability, oxygen permeability, and lysozyme deposition. The results show that increasing the proportion of hydrophobic network of HPSO in the IPN silicone hydrogel decreases equilibrium swelling ratio, ion permeability, Young's modulus, and lysozyme deposition; on the contrary, increased tensile strength, elongation at break and oxygen permeability. Puerarin and ketoconazole were used as models to evaluate the drug loading and in vitro release behavior of the silicone hydrogels. It is revealed that the amount of loaded drugs in the hydrogel decreases with the increase of HPSO network in the hydrogels. All the silicone hydrogels exhibit extended release behavior, especially for ketoconazole, the in vitro release is divided into two phases corresponding to the rapid release at initial 24 h and relatively slow release from 125 to 360 h.

[Cutinase production from short-chain organic acids by Thermobifida fusca].

We studied cutinase production from short-chain organic acids by Thermobifida fusca WSH03-11 to evaluate the possibility of converting municipal sludge to high value-added products. The optimum organic acid (8.0 g/L) and nitrogen source (1.5 g/L) concentrations were determined by the single factor experiments with butyric acid, propionic acid and acetic acid as the carbon sources. When lactic acid was used as the carbon source, the optimum organic acid (3.0 g/L) and nitrogen source (1.0 g/L) concentrations were obtained. Cutinase production by T. fusca WSH03-11 was further improved with butyric acid (by 31.0%), propionic acid (by 13.3%), acetic acid (by 43.8%) and lactic acid (by 73.2%) as carbon source, respectively, with the optimized cutin concentrations. Among these four short-chain organic acids, the average specific consumption rate of acetic acid was the highest, higher than that of propionic acid 1.3-folds, butyric acid 2.0-folds and lactic acid 2.2-folds. The highest cutinase activity reached 52.4 u/mL with butyric acid (8 g/L) as the sole carbon source, higher than that of lactic acid (3 g/L) 1.7-folds, acetic acid (8 g/L) 2.5-folds and propionic acid (8 g/L) 3.2-folds. The yield of cutinase activity on lactic acid (12.70 u/mg) higher than that of butyric acid 1.4-folds, propionic acid 3.0-folds and acetic acid 3.8-folds. T. fusca WSH03-11 consumed acetic acid firstly in mixed acids carbon sources, and the consumption of butyric acid was inhibited. Further studies indicated that the consumption rate of butyrate was decreased by 66.7% in the presence of 0.5 g/L acetic acid in the mixed acids. This was the first report concerning the production of cutinase by T. fusca with mixed organic acids as the carbon sources. The results presented here provided a novel and efficient approach to produce high value-add products from municipal sludge, and also established a foundation for the industrial production of cutinase by T. fusca WSH03-11 with cheap carbon sources from the processing of municipal sludge.