Ultrathin Two-Dimensional BiOCl-Bi2 S3 -Cu2 S Ternary Heterostructures with Enhanced LSPR effect for NIR Photonic Bacterial Disinfection.

Photonic disinfection, particularly near-infrared (NIR) light triggered antibacterial, has emerged as a highly promising solution for combating pathogenic microbes due to its spatiotemporal operability, safety, and low cost of apparatus. However, it remains challenging to construct NIR-responsive antibacterial agents with high light-converting efficacy and elucidate synergistic mechanisms. In this work, ultrathin two-dimensional (2D) BiOCl-Bi2 S3 -Cu2 S ternary heterostructures that can efficiently kill drug-resistant bacteria were synthesized by doping 0D Bi2 S3 and Cu2 S nanoparticles in the 2D BiOCl nanosheets via a facile one-pot hydrothermal method. Notably, the incorporation of Cu2 S nanoparticles bestows strong NIR light-harvesting capability to the composite nanosheets due to their localized surface plasmon resonance (LSPR). Upon NIR light illumination, the BiOCl-Bi2 S3 -Cu2 S nanosheets can achieve enhanced photonic hyperthermia and reaction oxygen species (ROS) generation, serving as single light-activated bi-functional photothermal/photodynamic therapeutics. High-speed hot electrons and large local electronic fields caused by LSPR might play an important role in thermal vibrations and effective carrier separations, respectively. Benefiting from the unique ternary heterostructures, both the photothermal conversion and ROS generation efficacy of BiOCl-Bi2 S3 -Cu2 S nanosheets are significantly improved compared to the binary BiOCl-Cu2 S or BiOCl-Bi2 S3 nanosheets. Accordingly, the ternary composite nanosheets can effectively kill bacteria via the NIR-driven photonic disinfection mechanism. This work presents a new type of 2D composite nanosheets with ternary heterostructures for NIR photonic disinfection.

First Report of Lasiodiplodia theobromae Causing Brown Leaf Spot on Bruguiera gymnorrhiza in China.

Bruguiera gymnorrhiza (Linn.) Sav. is a dominant tree species of mangrove forests in tropical coastal areas of China. This species is commonly used for the greening of tidal flats and seawalls in tropical and subtropical regions (Allen, & Duke 2000). A survey that was conducted from August to September 2020, in the mangrove national nature reserve at Zhanjiang, Guangdong Province, South China. Brown leaf spot symptoms were observed on Bruguiera gymnorrhiza and disease incidence was over 10% (200 investigated trees). Symptomatic small spots initially appeared at the middle or edges of leaves, enlarged irregularly, and developed into brown necrotic spots with dying curly edges. The color of the lesion's center changed to dark brown or gray. To identify the causative agent, twenty diseased leaves were sampled for pathogen isolation. Affected foliar tissues cut into 5 × 5 mm pieces, disinfected in 75% ethanol for 2 mins, rinsed in sterile distilled water, and then air dried under a sterilized filter paper. Leaf pieces were plated onto potato dextrose agar (PDA) in Petri dishes and then incubated at 28°C in darkness for 3-5 days. Hyphal tips of fungal colonies growing from the tissue pieces were subcultured onto fresh PDA to obtain pure single hyphae cultures. The fungal colonies were initially composed of white aerial mycelia, but turned gray after 7 days. Immature conidia were hyaline, subovoid, and aseptate while mature conidia becoming dark brown, one-septate with longitudinal stripes, the length/width ratio is 19.98 to 29.50 µm (average 24.37 µm; n = 50) × 11.99 to 14.45 µm (average 13.09 µm; n = 50). On the basis of morphological features all isolates were identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl (Alves et al. 2008). For DNA-based identification, the internal transcribed spacer (ITS) region gene and fragment of elongation factor 1-alpha (EF1-α) gene of the three isolates were amplified and sequenced following the methods described in a previous study (White et al. 1990, Carbone & Kohn 1999). The obtained sequences of ITS and EF1-α were deposited in GenBank with accession numbers OK644200 and OL345571. The BLAST results showed at least 99.60% similarity with the sequences of Lasiodiplodia theobromae (ITS, MT644474.1 [99.79%]; EF1-a, MK961975.1 [99.60%]). To fulfill Koch's postulates, PDA plugs with actively growing mycelium of the isolates were inoculated on the leaves of Bruguiera gymnorrhiza plants that were wounded by using a sterilized needle or scalpel. Inoculated leaves were covered with sterilized wet cotton, and the plants were kept at 28°C and 80% relative humidity. The inoculated plants showed leaf spot symptoms that were similar to those previously observed in the field after 1-2 days, whereas control leaves remained healthy. Lasiodiplodia theobromae was consistently isolated from inoculated leaves again. Lasiodiplodia theobromae (Botryosphaeriaceae) is a plurivorous pathogen in a wide variety of hosts, mostly prevalent in tropical and subtropical climate regions. It has been previously reported to cause brown leaf spot on Broussonetia papyrifera (Luo et al. 2020), foliar diseases on Camellia oleifera (Zhu et al. 2014) and Kadsura longipedunculata (Fan et al. 2020). To our knowledge, this is the first report of Lasiodiplodia theobromae causing brown leaf spot on Bruguiera gymnorrhiza plants in China and worldwide. Our findings will help to make management strategies for control of this disease on Bruguiera gymnorrhiza.

First Report of Pseudoidium santalacearum Causing Foliar Powdery Mildew on Santalum album in Guangdong Province, China.

Santalum album Linn is an evergreen and facultative root hemiparasitic tree. It is attached to host roots through haustorium to withdraw water and nutrients. Its aromatic heartwood, honored as "Green Gold", is widely used in perfumes, incense, medicine, and skin cancer prevention (Sandeep and Manohara 2019, Polaiah et al. 2020). From February to June 2022, powdery mildew was observed on over 80% of S. album in the nursery with a mean temperature and relative humidity of 30/22°C (day/night) and 55/82% (day/night) at the Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangdong, China (23°11'N, 113°23'E). Initial symptoms were circular to irregular white colonies on the leaf surface (Fig. 1). As the disease progressed, white mycelia covered the entire leaf surface and premature defoliation of the infected leaf was observed. Then a bare stem remained and subsequently desiccated (Sundararaj et al. 2022). Infected leaves with mycelia were collected and observed under a Zeiss AX10 microscope. Foot cells of conidiophores (n = 30) were straight to slightly curved cylindrical, and the length and width of foot cells were up to 24.8 to 44.6 × 8.2 to 11.7 µm. Conidiophores (n = 30) were straight, 83.5 to 127.3 µm long × 6.6 to 7.6 µm wide and produced three immature conidia in chains. Conidia (n = 30) were elliptical to cylindrical, measured 31.3 to 41.2 µm × 11.3 to 13.7 µm. The sexual stage was not found. The morphological characterization of our samples was consistent with powdery mildew of S. album in India, termed Pseudoidium santalacearum (Patel et al. 2015). However, the molecular identification was not performed. In this study, we carefully collected the mildew and extracted the genomic DNA. The internal transcribed spacer (ITS) region of rDNA was amplified using universal primers ITS1 and ITS4 (White et al. 1990). The ITS sequences of the three samples (GenBank Accession No. OQ746371, OQ746372, and OQ746373) were all more than 99% identical with the sequence of Erysiphe palczewskii on Caragana arborescens (GenBank Accession No. LC010048) (Takamatsu et al. 2015). It is known that Erysiphe containing chasmothecia belongs to teleomorph, whereas Pseudoidium is an asexual morph of Erysiphe, belonging to anamorph (Hsiao et al. 2022, Meeboon and Takamatsu 2016). In our samples, there was no chasmothecia, and the morphological characterization was consistent with P. santalacearum (Patel et al. 2015). Therefore, we classified it as P. santalacearum. Phylogenetic analysis showed that P. santalacearum had a closer relationship with the E. palczewskii (Fig. 2). Pathogenicity tests were conducted by gently pressing the infected leaves onto five healthy S. album plants. Five non-inoculated plants were used as controls. The plants were placed in a growth chamber (Light/Dark: 16 h/8 h, temperature: 25 ± 2°C). Inoculated leaves developed powdery mildew symptoms after 7-12 days, whereas the control plants remained symptomless (Fig. 1). Morphological and molecular characters of the fungus on the inoculated plants were identical to those on naturally infected S. album, fulfilling Koch's postulates. To our knowledge, this is the first report of P. santalacearum on S. album in Guangdong, China. Powdery mildew can generally result in a high mortality of S. album seedlings. Therefore, identification of the pathogen provides a scientific basis for effective diagnosis and prevention of the disease and contribute to an appropriate nursery management of S. album seedlings.

Combined transcriptome and metabolome analysis of Nerium indicum L. elaborates the key pathways that are activated in response to witches' broom disease.

BACKGROUND: Nerium indicum Mill. is an ornamental plant that is found in parks, riversides, lakesides, and scenic areas in China and other parts of the world. Our recent survey indicated the prevalence of witches' broom disease (WBD) in Guangdong, China. To find out the possible defense strategies against WBD, we performed a MiSeq based ITS sequencing to identify the possible casual organism, then did a de novo transcriptome sequencing and metabolome profiling in the phloem and stem tip of N. indicum plants suffering from WBD compared to healthy ones. RESULTS: The survey showed that Wengyuen county and Zengcheng district had the highest disease incidence rates. The most prevalent microbial species in the diseased tissues was Cophinforma mamane. The transcriptome sequencing resulted in the identification of 191,224 unigenes of which 142,396 could be annotated. There were 19,031 and 13,284 differentially expressed genes (DEGs) between diseased phloem (NOWP) and healthy phloem (NOHP), and diseased stem (NOWS) and healthy stem (NOHS), respectively. The DEGs were enriched in MAPK-signaling (plant), plant-pathogen interaction, plant-hormone signal transduction, phenylpropanoid and flavonoid biosynthesis, linoleic acid and α-linoleic acid metabolism pathways. Particularly, we found that N. indicum plants activated the phytohormone signaling, MAPK-signaling cascade, defense related proteins, and the biosynthesis of phenylpropanoids and flavonoids as defense responses to the pathogenic infection. The metabolome profiling identified 586 metabolites of which 386 and 324 metabolites were differentially accumulated in NOHP vs NOWP and NOHS and NOWS, respectively. The differential accumulation of metabolites related to phytohormone signaling, linoleic acid metabolism, phenylpropanoid and flavonoid biosynthesis, nicotinate and nicotinamide metabolism, and citrate cycle was observed, indicating the role of these pathways in defense responses against the pathogenic infection. CONCLUSION: Our results showed that Guangdong province has a high incidence of WBD in most of the surveyed areas. C. mamane is suspected to be the causing pathogen of WBD in N. indicum. N. indicum initiated the MAPK-signaling cascade and phytohormone signaling, leading to the activation of pathogen-associated molecular patterns and hypersensitive response. Furthermore, N. indicum accumulated high concentrations of phenolic acids, coumarins and lignans, and flavonoids under WBD. These results provide scientific tools for the formulation of control strategies of WBD in N. indicum.

First Report of Phytoplasma Belongs to 16SrV Group Associated with Witches'-broom Disease of Taxillus chinensis in China.

Taxillus chinensis (DC.) Danser is a hemiparasitic shrub, widespread in Southern China (Fu et al., 2001). T. chinensis can parasitize a wide range of species (e.g., Camellia spp., Ficus virens and Osmanthus fragrans), which obviously suppressed host growth by robbing nutrient and water through haustorium, causing considerable tree damage. During field visits to Dongguan (22°86'N, 13°97'E) and Guangzhou (23°19'N, 113°31'E), Guangdong Province, in April-July 2021, the typical phytoplasma-suspected symptom manifested as stunting, leaflet, leaf chlorosis and witches'-broom were observed in almost 36% of T. chinensis plants. Leaf samples were collected from six randomly collected plants with symptoms and six symptomless plants (Fig 1). Among them, half of T. chinensis plants parasitized on the host Elaeocarpus sylvestris, the other half on the O. fragrans. No apparent symptoms were observed on both two host plants. Total DNA was extracted from 0.5 g fresh leaf of T. chinensis plants with and without symptoms, as well as two host plants E. sylvestris and O. fragrans, using the CTAB method (Doyle et al., 1990). Nested polymerase chain reactions (PCRs) were performed on DNA extracts of all tested plants with primer pairs of P1/P7 and R16mF2/R16mR1 for 16S rRNA gene (Lee et al., 1993) and rp(v)F1/rpR1 for rp gene (Lee et al., 1998). All amplicons were obtained from symptomatic samples of T. chinensis and host plant E. sylvestris, whereas no such products resulted from DNAs of symptomless plants and O. fragrans. The amplicons were purified and sequenced by Sanger method (Rui Biotech, Guangzhou, China). The amplicon of 16S rRNA and rp genes is 1346 bp and 938 bp, respectively. BLAST comparison of the 16S rRNA (accession no. OL412744) and rp (accession no. OL473789) sequences of the T. chinensis witches'-broom phytoplasma yielded 99.6% sequence identity with those of phytoplasmas of group 16SrV jujube witches'-broom (JWB) phytoplasma (accession no. CP025121 for 16S rRNA gene and AF396941 for rp gene). The 16S rRNA gene sequence of phytoplasma in host plant E. sylvestris (accession no. OM885990) is 99.7% similarity to the 'Elaeocarpus zollingeri' yellows phytoplasma (accession no. LC257960) and 99.4% similarity to the 'Elaeocarpus sylvestris' decline phytoplasma (accession no. MW553140), but 95.8% similarity to the 16S rRNA gene of phytoplasma in T. chinensis. The virtual RFLP tool, iPhyClassifier delineated the T. chinensis phytoplasma (accession no. OL412744) to group 16SrV-B (accession no. AB052876) with the similarity coefficient 1.0 (Fig 2), and phytoplasma in E. sylvestris to group 16Sr group XXXII with the similarity coefficient 0.97. Phylogeny analyses of 16S rRNA and rp genes (MEGA version 7.0.14, USA) using reference phytoplasmas from GenBank confirmed sequencing results and placed the T. chinensis phytoplasma in group 16SrV-B (Fig. 3 and 4). In China, the 16SrV-B phytoplasma group has been reported in Amaranthus retroflexus (Yang et al., 2011), Liriodendron chinense (Li et al., 2012), Prunus salicina (Gao et al., 2020) and sweet potato (Li et al., 2021). This is the first report of a 'Ca. Phytoplasma ziziphi', 16SrV-B related phytoplasma associated with parasitic T. chinensis in China. The results of this study indicate that T. chinensis could be a vector to spread phytoplasmas 16SrV group through parasitism and this can be helpful for related research.

Pseudomonas quercus sp. nov, associated with leaf spot disease of Quercus mongolica.

Two Gram-negative, aerobic, motile bacteria strains were isolated from leaf spot disease of Quercus mongolica. Strain hsmgli-8T has 99.86 % 16S rRNA gene sequence similarity to LY10J, and the highest 16S rRNA gene sequence similarity to Pseudomonas cerasi 58T (97.2 %), then Pseudomonas ficuserectae JCM 2400T (97.18 %), Pseudomonas meliae CFBP 3225T, Pseudomonas tremae CFBP 6111T and Pseudomonas congelans DSM 14939T (all 97.12 %), and less than 97.1 % similarity to other recognized species. In phylogenetic trees based on 16S rRNA gene and multilocus sequence data, the two novel strains form a separate branch, indicating that they do not belong to any Pseudomonas group and subgroup, and should belong to a novel species within the genus Pseudomonas. This assertion is also supported by the results of genome average nucleotide identity analysis. The major fatty acids are C16 : 0, C18 : 1 ω7c and/or C18 : 1 ω6c, C16 : 1 ω7c and/or C16 : 1 ω6c. Polar lipids include phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, aminolipid and seven uncharacterized phospholipids. The predominant respiratory quinone is Q-9. The DNA G+C content is 59.45-59.50 mol%. Based on these data, we propose that the two novel strains should be assigned as a novel species within the genus Pseudomonas. We propose that the novel strains be named Pseudomonas quercus sp. nov. The type strain is hsmgli-8T (=CFCC 15739T=LMG 31544T).

Whole genome sequencing and genome annotation of the wild edible mushroom, Russula griseocarnosa.

Russula griseocarnosa is a species of edible ectomycorrhizal fungi with medicinal properties that grows in southern China. Total DNA was isolated from a fresh fruiting body of R. griseocarnosa and subjected to sequencing using Illumina Hiseq with the PacBio RS sequencing platform. Here, we present the 64.81 Mb draft genome map of R. griseocarnosa based on 471 scaffolds and 16,128 coding protein genes. The gene annotation of protein coding genes was used to obtain corresponding annotations by blastp. Phylogenetic analysis revealed a close evolutionary relationship of R. griseocarnosa to Heterobasidion irregulare and Stereum hirsutum in the core Russulales clade. The R. griseocarnosa genome encodes a repertoire of enzymes engaged in carbohydrate and polysaccharide metabolism, along with cytochrome P450s and secondary metabolite biosynthesis. The genome content of R. griseocarnosa provides insights into the genetic basis of its reported medicinal properties and serves as a reference for comparative genomics of fungi.

Sphingomonas corticis sp. nov., and Sphingobacterium corticibacterium sp. nov., from bark canker.

Two Gram-stain-negative, aerobic, non-motile bacterial strains, 36D10-4-7T and 30C10-4-7T, were isolated from bark canker tissue of Populus × euramericana, respectively. 16S rRNA gene sequence analysis revealed that strain 36D10-4-7T shows 98.0 % sequence similarity to Sphingomonas adhaesiva DSM 7418T, and strain 30C10-4-7T shows highest sequence similarity to Sphingobacterium arenae H-12T (95.6 %). Average nucleotide identity analysis indicates that strain 36D10-4-7T is a novel member different from recognized species in the genus Sphingomonas. The main fatty acids and respiratory quinone detected in strain 36D10-4-7T are C18 : 1 ω7c and/or C18 : 1 ω6c and Q-10, respectively. The polar lipids are diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, aminolipid, phosphatidylethanolamine, sphingoglycolipid, two uncharacterized phospholipids and two uncharacterized lipids. For strain 30C10-4-7T, the major fatty acids and menaquinone are iso-C15 : 0, C16 : 1 ω7c and/or C16 : 1 ω6c and iso-C17 : 0 3-OH and MK-7, respectively. The polar lipid profile includes phosphatidylethanolamine, phospholipids, two aminophospholipids and six unidentified lipids. Based on phenotypic and genotypic characteristics, these two strains represent two novel species within the genera Sphingomonas and Sphingobacterium. The name Sphingomonas corticis sp. nov. (type strain 36D10-4-7T=CFCC 13112T=KCTC 52799T) and Sphingobacterium corticibacterium sp. nov. (type strain 30C10-4-7T=CFCC 13069T=KCTC 52797T) are proposed.

Ultrastructure of Antennal Morphology and Sensilla of Teak Skeletonizer, Eutectona machaeralis Walker (Lepidoptera: Crambidae).

The leaf skeletonizer, Eutectona machaeralis (Walker) (Lepidoptera: Crambidae), is a severe insect pest of teak trees (Tectona grandis L.f.) in China. To provide some basic evidence for future semiochemical-based management strategies of E. machaeralis, the morphology, ultrastructure, and distribution of antennal sensilla of adults were observed under scanning and transmission electron microscopy. The shape and structure of antenna were similar between males and females, both being filiform. However, the antennal length of males was significantly longer than that of females. Eight morphological sensilla types were observed in both sexes: Böhm's bristles, sensilla trichodea, sensilla basiconica, sensilla chaetica, sensilla styloconica, sensilla coeloconica, sensilla auricillica, and sensilla squamiformia. Significant sexual dimorphism of the sensilla dimensions was found, especially in sensillar length. The putative and potential functions of the different sensilla types are discussed based on the fine structures of the cuticular walls and dendrites of the different sensilla types. We expect these results to help lay a solid foundation for future functional research and develop further investigations of E. machaeralis.

Fungal Systematics and Evolution: FUSE 5.

Thirteen new species are formally described: Cortinarius brunneocarpus from Pakistan, C. lilacinoarmillatus from India, Curvularia khuzestanica on Atriplex lentiformis from Iran, Gloeocantharellus neoechinosporus from China, Laboulbenia bernaliana on species of Apenes, Apristus, and Philophuga (Coleoptera, Carabidae) from Nicaragua and Panama, L. oioveliicola on Oiovelia machadoi (Hemiptera, Veliidae) from Brazil, L. termiticola on Macrotermes subhyalinus (Blattodea, Termitidae) from the DR Congo, Pluteus cutefractus from Slovenia, Rhizoglomus variabile from Peru, Russula phloginea from China, Stagonosporopsis flacciduvarum on Vitis vinifera from Italy, Strobilomyces huangshanensis from China, Uromyces klotzschianus on Rumex dentatus subsp. klotzschianus from Pakistan. The following new records are reported: Alternaria calendulae on Calendula officinalis from India; A. tenuissima on apple and quince fruits from Iran; Candelariella oleaginescens from Turkey; Didymella americana and D. calidophila on Vitis vinifera from Italy; Lasiodiplodia theobromae causing tip blight of Dianella tasmanica 'variegata' from India; Marasmiellus subpruinosus from Madeira, Portugal, new for Macaronesia and Africa; Mycena albidolilacea, M. tenuispinosa, and M. xantholeuca from Russia; Neonectria neomacrospora on Madhuca longifolia from India; Nothophoma quercina on Vitis vinifera from Italy; Plagiosphaera immersa on Urtica dioica from Austria; Rinodina sicula from Turkey; Sphaerosporium lignatile from Wisconsin, USA; and Verrucaria murina from Turkey. Multi-locus analysis of ITS, LSU, rpb1, tef1 sequences revealed that P. immersa, commonly classified within Gnomoniaceae (Diaporthales) or as Sordariomycetes incertae sedis, belongs to Magnaporthaceae (Magnaporthales). Analysis of a six-locus Ascomycota-wide dataset including SSU and LSU sequences of S. lignatile revealed that this species, currently in Ascomycota incertae sedis, belongs to Pyronemataceae (Pezizomycetes, Pezizales).

In Situ Observation of Dynamic Wetting Transition in Re-Entrant Microstructures.

Re-entrant microstructures exhibit excellent wetting stability under different pressure levels, but the underlying mechanism determined by wetting transition behavior at the microscale level remains unclear. We propose the "wetting chip" method for in situ assessment of the dynamic behavior of wetting transition in re-entrant microstructures. High sag and transverse depinning were observed in re-entrant microstructures. Analysis indicated that high sag and transverse depinning mainly influenced the stability of the structures. The threshold pressure and longevity of wetting transition were predicted and experimentally verified. The design criteria of wetting stability, including small geometry design, hydrophobic material selection, and sidewall condition, were also presented. The proposed method and model can be applied to different shapes and geometry microstructures to elucidate wetting stability.

Corticicoccus populi gen. nov., sp. nov., a member of the family Staphylococcaceae, isolated from symptomatic bark of Populus × euramericana canker.

Two Gram-stain-positive, aerobic, non-motile, bacterial strains were isolated from symptomatic bark tissue of Populus × euramericana canker. The isolates were able to grow between 10 and 37 °C, at pH 6-10 and with 0-4 % (w/v) NaCl, with optimal growth at 28-30 °C, pH 7.0-8.0 and with 2 % (w/v) NaCl The strains were found to be oxidase and catalase positive. The menaquinone of strain 26D10-3-4T was MK-7 and the peptidoglycan type A3α based on l-Lys-Gly3-?Ala. The polar lipid profiles of strain 26D10-3-4T showed diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids and three unidentified glycolipids, and the major fatty acids found were anteiso-C15 : 0, iso-C15 : 0, iso-C17 : 0 and anteiso-C17 : 0. The DNA G+C content was 38.2 mol%. The two novel isolates shared the highest 16S rRNA gene sequence similarity with Salinicoccus qingdaonensis ZXM223T (95.0 %). Based on phenotypic and genotypic characteristics, these two strains represent a novel species of a new genus of the family Staphylococcaceae; the name Corticicoccus populi gen. nov., sp. nov. is proposed. The type strain of the type species is 26D10-3-4T (=CFCC 12725T=KCTC 33575T). An additional strain of the species is 9-4-1.

Chromosome-Level Assembly and Comparative Genomic Analysis of Suillus bovinus Provides Insights into the Mechanism of Mycorrhizal Symbiosis.

Suillus bovinus is a wild edible ectomycorrhizal fungus with important economic and ecological value, which often forms an ectomycorrhiza with pine trees. We know little about the mechanisms associated with the metabolism and symbiosis of S. bovinus and its effects on the nutritional value. In this study, the whole-genome sequencing of S. bovinus was performed using Illumina, HiFi, and Hi-C technologies, and the sequencing data were subjected to genome assembly, gene prediction, and functional annotation to obtain a high-quality chromosome-level genome of S. bovinus. The final assembly of the S. bovinus genome includes 12 chromosomes, with a total length of 43.03 Mb, a GC content of 46.58%, and a contig N50 size of 3.78 Mb. A total of 11,199 coding protein sequences were predicted from genome annotation. The S. bovinus genome contains a large number of small secreted proteins (SSPs) and genes that encode enzymes related to carbohydrates, as well as genes related to terpenoids, auxin, and lipochitooligosaccharides. These genes may contribute to symbiotic processes. The whole-genome sequencing and genetic information provide a theoretical basis for a deeper understanding of the mechanism of the mycorrhizal symbiosis of S. bovinus and can serve as a reference for comparative genomics of ectomycorrhizal fungi.

Four new species of Russulasubsect.Cyanoxanthinae from China (Russulales, Russulaceae).

Four new species of Russulasubsect.Cyanoxanthinae, viz. Russulaatrochermesina Y.L. Chen & J.F. Liang, R.lavandula Y.L. Chen, B. Chen & J.F. Liang, R.lilaceofusca Y.L. Chen & J.F. Liang and R.perviridis Y.L. Chen, B. Chen & J.F. Liang, from China are proposed, based on morphological and molecular evidence. Russulaatrochermesina can be distinguished by its violet pileus with tuberculate-striate margin, distant lamellae that stain greyish-yellow when bruised, basidiospores ornamented by isolated warts, wide hymenial cystidia on lamellae edges, cystidia content negative reaction in sulphovanillin and branched subterminal cells in pileipellis. Russulalavandula has a purplish-white to violet red pileus with a yellow centre, frequently present lamellulae and furcations, stipe often with pale yellow near the base, isolated basidiospores ornamentation and unbranched cuticular hyphal terminations, while R.lilaceofusca is characterised by its lilac brown to dark brown pileus, crowded lamellae with lamellulae and furcations, stipe often turning reddish-yellow when bruised, subreticulate basidiospores ornamentation and clavate hymenial cystidia often with capitate appendage whose contents that change to reddish-black in sulphovanillin. Russulaperviridis is characterised by its large basidiomata, smooth pileus surface, frequently present lamellulae and furcations, stipe with yellow-brown tinge, globose to broadly ellipsoid basidiospores with subreticulate ornamentation, long hymenial cystidia that turn greyish-black in sulphovanillin and symbiotic with Quercussemecarpifolia. Phylogenetic analyses, based on multi-gene ITS+LSU+mtSSU+rpb2, indicate that R.atrochermesina, R.lavandula, R.lilaceofusca and R.perviridis are closely related to R.pallidirosea and R.purpureorosea, R.banwatchanensis, R.lakhanpalii and R.nigrovirens, respectively.

Structure, Synthesis, and Bioassays of Sex Pheromone for Pyrausta machaeralis (Lepidoptera: Crambidae).

The leaf skeletonizer, Pyrausta machaeralis (Lepidoptera: Crambidae), is a serious insect pest of teak (Tectona grandis) in China. The application of insect pheromones is widely applied as an environmentally friendly technology for integrated pest management (IPM). In the present study, crude extracts of sex pheromone glands of calling P. machaeralis females were collected and then analyzed using gas chromatography/electroantennographic detection (GC/EAD) and gas chromatography-mass spectrometry (GC-MS). The combination of infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry was used for structure identification. Afterward, their electrophysiological and behavioral activity was evaluated in the laboratory and field. Herein, we eventually determined two active components, E-11-tetradecenyl acetate (E11-14:Ac) and Z-11-tetradecenyl acetate (Z11-14:Ac), at a ratio of 96:4, as the sex pheromone of P. machaeralis. The identification of sex pheromones would facilitate the development of efficient strategies for monitoring and controlling the field populations of P. machaeralis.

Host root exudates initiate a foraging preference by the root parasite Santalum album.

Haustoria of root-parasitic plants draw nutrients from the roots of host species. While recent studies have assessed host preferences of parasitic plants, how root-exuded chemicals can mediate host tropism and selection by root-parasitic plants is poorly understood. Under greenhouse conditions, we performed two pot experiments to determine whether the root parasite Santalum album selectively forages for superior hosts (N2-fixing Acacia confusa Merr. or Dalbergia odorifera T. Chen) rather than for inferior hosts (non-N2-fixing Bischofia polycarpa (levl.) Airy Shaw or Dracontomelon duperreranum Pierre), and whether S. album uses host root exudates and/or specific chemicals in these root exudates to locate and trigger haustorium formation. Lateral roots and haustoria of S. album seedlings exhibited greater growth in the direction of D. odorifera roots than toward roots from the other three hosts. Comparative metabolic analysis revealed that D. odorifera root exudates were enriched in isoflavonoid, flavonoid and flavone/flavonol biosynthesis pathways, and that the relative contents of flavonoids were significantly greater in the root exudates of D. odorifera than in those of the other three hosts. Root exudates from D. odorifera significantly promoted S. album root growth, haustorium formation and reactive oxygen species accumulation in haustoria. Our results demonstrate that the key step in plant parasitism by S. album is based on root exudation by a host plant; the exudates function as a metabolite signal that activate lateral root growth and haustorium formation. Our results also indicate that flavonoids in the root exudates could play an important role in S. album foraging activity. Information on the responses of root parasites to host root exudates and/or haustorium-inducing chemicals may be useful for selecting superior host species to plant with valuable species of root parasites.

Nitrogen rather than carbon released by litter decomposition mediates nutrient relationships in a multispecies forest plantation with hemiparasite.

Hemiparasitic plants influence community composition by altering nutrient cycling. Although hemiparasites can deplete a host's nutrients via parasitism, their potentially positive effects on nutrient return to multispecies communities remain unclear. We used 13C/15N-enriched leaf litter of the hemiparasite sandalwood (Santalum album, Sa) and two N2-fixing hosts of acacia (Acacia confusa, Ac) and rosewood (Dalbergia odorifera, Do), either as a single-species or mixed-species litter, to elucidate nutrient return by litter decomposition in an acacia-rosewood-sandalwood mixed plantation. We determined litter decomposition rates, litter C and N release, and the resorption of C and N from seven litter types (Ac, Do, Sa, AcDo, AcSa, DoSa, and AcDoSa) at 90, 180, 270, and 360 days. We found that non-additive mixing effects were common during the decomposition of mixed litter and depended on litter type and decomposition timing. After rapidly increasing for around 180 days, both the decomposition rate and release of C and N from litter decomposition declined, but the resorption of litter-released N by the target tree species increased. There was a 90-day lag time between the release and resorption of litter N. Sandalwood litter consistently stimulated the litter mass loss of its mixed litter. Rosewood had the highest release rate of litter 13C or 15N from litter decomposition, but resorbed more litter 15N into its leaves than other tree species. In contrast, acacia had a lower decomposition rate and a higher 15N resorption in its roots. Initial litter quality was closely correlated with the release of litter 15N. Neither the release nor resorption of litter 13C significantly differed among sandalwood, rosewood, and acacia. Our study demonstrates that the fate of litter N, rather than litter C, mediates nutrient relationships in mixed sandalwood plantations and thus provides important silvicultural implications for planting sandalwood with other host species.

Heterojunction structured BiOCl-Bi2S3 nanosheets as mitochondria-targeted near-infrared photothermal and photodynamic therapy agent.

Mitochondria-targeted phototherapy, especially combined photothermal therapy (PTT) and photodynamic therapy (PDT), has been regarded as an attractive strategy for the treatment of tumor. In this study, a facile approach to prepare two-dimensional (2D) BiOCl-Bi2S3 nanostructures was developed, where Bi2S3 quantum dots were doped in/on the ultrathin BiOCl nanosheets, forming a p-n heterojunction. The BiOCl-Bi2S3 shows favorable photothermal conversion efficiency (32%) and synergistically reactive oxygen species (ROS) generating capability under near-infrared (NIR) irradiation. Moreover, the conjugation of synthetic targeting ligand to the surface of BiOCl-Bi2S3 endows the heterojunction effective tumor targeting ability and selective mitochondrial accumulation. The combined cancer targeting ability and synergistic PTT/PDT permit enhanced cooperative phototherapeutic efficiency of the 2D heterojunction. This study provides an attractive way for designing new class of heterostructure materials for potential applications in subcellular-targeted phototherapy.

[Biodiversity of Rhizobia associated with Acacia melanoxylon grown in South China].

OBJECTIVE: This study aimed to investigate the genetic diversity of 174 isolates of symbiotic bacteria associated with Acacia melanoxylon obtained from 15 sampling sites in Guangdong, Fujian and Jiangxi provinces of China. METHODS: The 16S rDNA restriction fragment length polymorphism (RFLP) and phylogenetic analyses of the 16S rDNA and housekeeping genes (recA, glnII and atpD). RESULTS: In the 16S rDNA PCR-RFLP analysis, 9 rDNA types were identified among the 174 isolates; Phylogenetic analyses based on 16S rDNA and housekeeping gene sequences indicated that 34 representative isolates belonged to the genus Bradyrhizobium, Rhizobium, Mesorhizobium in Alpha-Proteobacteria, and the most closely related strains are Bradyrhizobium liaoningense, Bradyrhizobium betae, Bradyrhizobium cytisi, Rhizobium multihospitium and Mesorhizobium plurifarium. CONCLUSION: All of the isolates could be identified to general, and Bradyrhizobium, Rhizobium or Mesorhizobium could be the dominant microsymbiont. The microsymbionts associated with Acacia melanoxylon showed relative genetic diversity.

Analysis of Rac/Rop Small GTPase Family Expression in Santalum album L. and Their Potential Roles in Drought Stress and Hormone Treatments.

Plant-specific Rac/Rop small GTPases, also known as Rop, belong to the Rho subfamily. Rac proteins can be divided into two types according to their C-terminal motifs: Type I Rac proteins have a typical CaaL motif at the C-terminal, whereas type II Rac proteins lack this motif but retain a cysteine-containing element for membrane anchoring. The Rac gene family participates in diverse signal transduction events, cytoskeleton morphogenesis, reactive oxygen species (ROS) production and hormone responses in plants as molecular switches. S. album is a popular semiparasitic plant that absorbs nutrients from the host plant through the haustoria to meet its own growth and development needs. Because the whole plant has a high use value, due to the high production value of its perfume oils, it is known as the "tree of gold". Based on the full-length transcriptome data of S. album, nine Rac gene members were named SaRac1-9, and we analyzed their physicochemical properties. Evolutionary analysis showed that SaRac1-7, AtRac1-6, AtRac9 and AtRac11 and OsRac5, OsRacB and OsRacD belong to the typical plant type I Rac/Rop protein, while SaRac8-9, AtRac7, AtRac8, AtRac10 and OsRac1-4 belong to the type II Rac/ROP protein. Tissue-specific expression analysis showed that nine genes were expressed in roots, stems, leaves and haustoria, and SaRac7/8/9 expression in stems, haustoria and roots was significantly higher than that in leaves. The expression levels of SaRac1, SaRac4 and SaRac6 in stems were very low, and the expression levels of SaRac2 and SaRac5 in roots and SaRac2/3/7 in haustoria were very high, which indicated that these genes were closely related to the formation of S. album haustoria. To further analyze the function of SaRac, nine Rac genes in sandalwood were subjected to drought stress and hormone treatments. These results establish a preliminary foundation for the regulation of growth and development in S. album by SaRac.