A tau class glutathione S-transferase in tea plant, CsGSTU45, facilitates tea plant susceptibility to Colletotrichum camelliae infection mediated by jasmonate signaling pathway.

Tea plant [Camellia sinensis (L.) O. Kuntze], as one of the most important commercial crops, frequently suffers from anthracnose caused by Colletotrichum camelliae. The plant-specific tau (U) class of glutathione S-transferases (GSTU) participates in ROS homeostasis. Here, we identified a plant-specific GST tau class gene from tea plant, CsGSTU45, which is induced by various stresses, including C. camelliae infection, by analyzing multiple transcriptomes. CsGSTU45 plays a negative role in disease resistance against C. camelliae by accumulating H2 O2 . JA negatively regulates the resistance of tea plants against C. camelliae, which depends on CsGSTU45. CsMYC2.2, which is the key regulator in the JA signaling pathway, directly binds to and activates the promoter of CsGSTU45. Furthermore, silencing CsMYC2.2 increased disease resistance associated with reduced transcript and protein levels of CsGSTU45, and decreased contents of H2 O2 . Therefore, CsMYC2.2 suppresses disease resistance against C. camelliae by binding to the promoter of the CsGSTU45 gene and activating CsGSTU45. CsJAZ1 interacts with CsMYC2.2. Silencing CsJAZ1 attenuates disease resistance, upregulates the expression of CsMYC2.2 elevates the level of the CsGSTU45 protein, and promotes the accumulation of H2 O2 . As a result, CsJAZ1 interacts with CsMYC2.2 and acts as its repressor to suppress the level of CsGSTU45 protein, eventually enhancing disease resistance in tea plants. Taken together, the results show that the JA signaling pathway mediated by CsJAZ1-CsMYC2.2 modulates tea plant susceptibility to C. camelliae by regulating CsGSTU45 to accumulate H2 O2 .

A functional study reveals CsNAC086 regulated the biosynthesis of flavonols in Camellia sinensis.

MAIN CONCLUSION: CsNAC086 was found to promote the expression of CsFLS, thus promoting the accumulation of flavonols in Camellia sinensis. Flavonols, the main flavonoids in tea plants, play an important role in the taste and quality of tea. In this study, a NAC TF gene CsNAC086 was isolated from tea plants and confirmed its regulatory role in the expression of flavonol synthase which is a key gene involved in the biosynthesis of flavonols in tea plant. Yeast transcription-activity assays showed that CsNAC086 has self-activation activity. The transcriptional activator domain of CsNAC086 is located in the non-conserved C-terminal region (positions 171-550), while the conserved NAC domain (positions 1-170) does not have self-activation activity. Silencing the CsNAC086 gene using antisense oligonucleotides significantly decreased the expression of CsFLS. As a result, the concentration of flavonols decreased significantly. In overexpressing CsNAC086 tobacco leaves, the expression of NtFLS was significantly increased. Compared with wild-type tobacco, the flavonols concentration increased. Yeast one-hybrid assays showed CsNAC086 did not directly regulate the gene expression of CsFLS. These findings indicate that CsNAC086 plays a role in regulating flavonols biosynthesis in tea plants, which has important implications for selecting and breeding of high-flavonols-concentration containing tea-plant cultivars.

The RasGEF MoCdc25 regulates vegetative growth, conidiation and appressorium-mediated infection in the rice blast fungus Magnaporthe oryzae.

Ras guanine nucleotide exchange factors (RasGEFs) can trigger Ras GTPase activities and play important roles in controlling various cellular processes in eukaryotes. Recently, it has been exhibited that RasGEF Cdc25 regulates morphological differentiation and pathogenicity in several plant pathogenic fungi. However, the role of RasGEFs in Magnaporthe oryzae is largely unknown. In this study, we identified and functionally characterized a RasGEF gene MoCDC25 in M. oryzae, which is orthologous to Saccharomyces cerevisiae CDC25. Targeted gene deletion mutants (ΔMocdc25) were completely nonpathogenic and were severely impaired in hyphal growth, conidiation and appressorium formation. The mutants exhibited highly sensitive response to osmotic, cell wall integrity or oxidative stresses. MoCdc25 physically interacts with the MAPK scaffold Mst50 and the putative Cdc42GEF MoScd1 in yeast two-hybrid assays. Moreover, we found that MoCdc25 was involved in regulating the phosphorylation of the MAP kinases (Pmk1, Mps1, and Osm1). In addition, the intracellular cAMP content in hyphae of the ΔMocdc25 mutants was significantly reduced compared to the parent strain Ku80 and the defect of appressorium formation of the mutants could be partially restored by the supplement of exogenous cAMP. Taken together, we conclude that the RasGEF MoCdc25 regulates vegetative growth, conidiation, appressorium formation and pathogenicity via MAPK and cAMP response pathways in M. oryzae.

A putative PKA phosphorylation site S227 in MoSom1 is essential for infection-related morphogenesis and pathogenicity in Magnaporthe oryzae.

In the rice blast fungus Magnaporthe oryzae, the cAMP signalling pathway plays a critical role in regulating leaf surface recognition and the initiation of appressorium development. Direct downstream targets of the cAMP signalling pathway are, however, not well-characterised. The MoSom1 protein functions downstream of the cAMP dependent protein kinase A (cAMP-PKA) and is essential for infection-related morphogenesis and pathogenicity. In this study, we show that mutation of a putative PKA phosphorylation site in MoSom1 is essential for its role in appressorium differentiation and pathogenicity in M. oryzae. Mutation of serine 227 in MoSom1 by deletion or serine (S) substitution to alanine (A), valine (V) or tyrosine (Y), resulted in defects of conidiation, appressorium-like structure formation and fungal pathogenicity. Western blot analysis confirmed that S227 in MoSom1 is a putative PKA phosphorylation site. Furthermore, a ΔMosom1 mutant showed reduced expression of PMK1 and was defective in Pmk1 phosphorylation, indicating that the Pmk1 mitogen-activated protein kinase (MAPK) acts downstream of MoSom1 in M. oryzae. We conclude that the cAMP-PKA pathway may regulate the Pmk1 MAPK pathway through MoSom1 during rice infection by the blast fungus. TAKE AWAYS: S227 is crucial for MoSom1 function in M. oryzae. S227 in MoSom1 was identified as a putative PKA phosphorylation site in M. oryzae. S227 is essential for infection-related morphogenesis and pathogenicity in M. oryzae.

The sorting nexin FgAtg20 is involved in the Cvt pathway, non-selective macroautophagy, pexophagy and pathogenesis in Fusarium graminearum.

The sorting nexin Atg20/Snx42 plays an important role in autophagy. The wheat head blight pathogen Fusarium graminearum contains an FgAtg20 protein orthologous to Saccharomyces cerevisiae Atg20/Snx42, but its function remains largely unknown. Here, we report a role for FgAtg20 in regulating morphogenesis and fungal pathogenicity. Cytological observation and Western blot analysis revealed that ΔFgAtg20 mutants are defective in vacuolar transport and proteolysis of GFP-FgAtg8, indicating that FgAtg20 is required for non-selective macroautophagy. Furthermore, we found that FgATG20 is necessary for the maturation of FgApe1, an indicator of the cytoplasm-to-vacuole targeting (Cvt) pathway. Immunoblot analysis displayed lower level of FgPex14, a peroxisomal integral membrane protein in ΔFgAtg20 mutants, suggesting that pexophagy is impaired. Furthermore, we demonstrate that FgAtg20 forms a complex with FgAtg1, FgAtg11, FgAtg17 and FgAtg24. When considered together, we conclude that FgAtg20 plays a critical role in vegetative growth, conidiation and pathogenicity of the head blight pathogen, and is involved in the Cvt pathway, non-selective macroautophagy and pexophagy.

Leucine biosynthesis is required for infection-related morphogenesis and pathogenicity in the rice blast fungus Magnaporthe oryzae.

The rice blast fungus Magnaporthe oryzae causes one of the most devastating crop diseases world-wide and new control strategies for blast disease are urgently required. We have used insertional mutagenesis in M. oryzae to define biological processes that are critical for blast disease. Here, we report the identification of LEU2A by T-DNA mutagenesis, which putatively encodes 3-isopropylmalate dehydrogenase (3-IPMDH) required for leucine biosynthesis, implicating that synthesis of this amino acid is required for fungal pathogenesis. M. oryzae contains a further predicted 3-IPMDH gene (LEU2B), two 2-isopropylmalate synthase (2-IPMS) genes (LEU4 and LEU9) and an isopropylmalate isomerase (IPMI) gene (LEU1). Targeted gene deletion mutants of LEU1, LEU2A or LEU4 are leucine auxotrophs, and severely defective in pathogenicity. All phenotypes associated with mutants lacking LEU1, LEU2A or LEU4 could be overcome by adding exogenous leucine. The expression levels of LEU1, LEU2A or LEU4 genes were significantly down-regulated by deletion of the transcription factor gene LEU3, an ortholog of Saccharomyces cerevisiae LEU3. We also functionally characterized leucine biosynthesis genes in the wheat pathogen Fusarium graminearum and found that FgLEU1, FgLEU3 and FgLEU4 are essential for wheat head blight disease, suggesting that leucine biosynthesis in filamentous fungal pathogens may be a conserved factor for fungal pathogenicity and, therefore, a potential target for disease control.

The putative deubiquitinating enzyme MoUbp4 is required for infection-related morphogenesis and pathogenicity in the rice blast fungus Magnaporthe oryzae.

Ubiquitination is a key regulatory mechanism that affects numerous important biological processes, including cellular differentiation and pathogenesis in eukaryotic cells. Attachment of proteins to ubiquitin is reversed by specialized proteases, deubiquitinating enzymes (DUBs), which are essential for precursor processing, maintaining ubiquitin homeostasis and promoting protein degradation by recycling ubiquitins. Here, we report the identification of a novel non-pathogenic T-DNA-tagged mutant T612 of Magnaporthe oryzae with a single insertion in the second exon of MoUBP4, which encodes a putative ubiquitin carboxyl-terminal hydrolase. Targeted gene deletion mutants of MoUBP4 are significantly reduced in mycelial growth, conidiation, and increased in tolerance to SDS and CR (Congo red) cell-wall damage. The ΔMoubp4 mutants are blocked in penetration and invasive growth, which results in the loss of pathogenicity. Many conidia produced by the ΔMoubp4 mutants are unable to form appressoria and mobilization and degradation of glycogen and lipid droplets are significantly delayed. Moreover, immunohybridization analysis revealed that total protein ubiquitination levels of the null mutants were significantly increased, indicating that MoUbp4 functions as a deubiquitination enzyme. Taken together, we conclude that MoUbp4 is required for deubiquitination, infection-related morphogenesis and pathogenicity in M. oryzae.

The putative histone-like transcription factor FgHltf1 is required for vegetative growth, sexual reproduction, and virulence in Fusarium graminearum.

The target of rapamycin (TOR) signaling pathway plays critical roles in regulating vegetative development and virulence in Fusarium graminearum. Previously, we have demonstrated that the putative type 2A phosphatase FgPpg1, a downstream component of the pathway, is important for hyphal growth, sporulation, DON biosynthesis and virulence. Here, we report the identification of FgHLTF1 putatively encoding a histone-like transcription factor by the transcriptome analysis of an ΔFgppg1 mutant. The FgHLTF1 expression was significantly down-regulated by the deletion of FgPPG1 or treatment with rapamycin. Analysis of an F. graminearum strain expressing green fluorescent protein (GFP) revealed that FgHltf1-GFP fusion protein mainly localized to the nucleus. Targeted gene deletion mutants of FgHLTF1 exhibited a significant reduction in vegetative growth, sexual reproduction and virulence. Moreover, the growth of the ΔFghltf1 mutants was restricted by hyperosmotic stresses. Unlike the wild-type strain, the mutants showed anomalous subcellular translocation of FgHog1-GFP under hyperosmotic conditions, suggesting that FgHLTF1 is associated with the high osmolarity glycerol response pathway. Taken together, we conclude that FgHLTF1 is transcriptionally regulated by the TOR signaling pathway and plays important roles in regulating vegetative growth, sexual reproduction, virulence and hyperosmotic stresses in F. graminearum.

FgRIC8 is involved in regulating vegetative growth, conidiation, deoxynivalenol production and virulence in Fusarium graminearum.

Proteins of the resistance to inhibitors of cholinesterase 8 (Ric8) group act as guanine nucleotide exchange factors (GEFs) and play important roles in regulating G-protein signaling in animals. In filamentous fungi, putative Ric8 orthologs have so far been identified in Magnaporthe oryzae, Neurospora crassa, Aspergillus nidulans and Aspergillus fumigatus. Here, we report the functional investigation of a potential RIC8 ortholog (FgRIC8) in the wheat head blight pathogen Fusarium graminearum. Targeted gene deletion mutants of FgRIC8 exhibited a significant reduction in vegetative growth, conidiation, pigment production as well as deoxynivalenol (DON) biosynthesis. Pathogenicity assays using a point-inoculated spikelet approach showed that the mutants were severely impaired in virulence on flowering wheat heads. Quantitative RT-PCR analysis revealed that genes encoding F. graminearum Gα (FgGpa1 and FgGpa3), Gß (FgGpb1) and Gγ (FgGpg1) subunits were significantly down-regulated in Fgric8 mutants. Moreover, we showed that FgRic8 physically interacts with both FgGpa1 and FgGpa3, but not FgGpa2, in yeast two-hybrid assays. The intracellular cAMP levels in Fgric8 mutants were significantly decreased compared to the isogenic wild-type strain. Taken together, our results indicate that FgRic8 plays critical roles in fungal development, secondary metabolism and virulence in F. graminearum and may act as a regulator of G protein alpha subunits.

A Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Didymella segeticola Causing Tea Leaf Spot.

Tea leaf spot caused by Didymella segeticola is an important disease that threatens the healthy growth of tea plants (Camellia sinensis) and results in reductions in the productivity and quality of tea leaves. Early diagnosis of the disease is particularly important for managing the infection. Loop-mediated isothermal amplification (LAMP) assay is an efficient diagnostic technique with the advantages of simplicity, specificity, and sensitivity. In this study, we developed a rapid, visual, and high-sensitivity LAMP assay for D. segeticola detection based on sequence-characterized amplified regions. Two pairs of amplification primers (external primers F3 and B3 and internal primers FIP and BIP) were designed based on a specific sequence in D. segeticola (NCBI accession number: OR987684). Compared to common pathogens of other genera in tea plants and other species in the Didymella genus (Didymella coffeae-arabicae, Didymella pomorum, and Didymella sinensis), the LAMP method is specific for detecting the species D. segeticola. The assay was able to detect D. segeticola at a minimal concentration of 1 fg/µL genomic DNA at an optimal reaction temperature of 65 °C for 60 min. When healthy leaves were inoculated with D. segeticola in the laboratory, the LAMP method successfully detected D. segeticola in diseased tea leaves at 72 h post inoculation. The LAMP assays were negative when the DNA samples were extracted from healthy leaves. Leaf tissues with necrotic lesions from 18 germplasms of tea plants tested positive for the pathogen by the LAMP assay. In summary, this study established a specific, sensitive, and simple LAMP method to detect D. segeticola, which provides reliable technical support for estimating disease prevalence and facilitates sustainable management of tea leaf spot.

Didymellaceae species associated with tea plant (Camelliasinensis) in China.

Tea plant is one of the most important commercial crops worldwide. The Didymellaceae fungi can cause leaf blight disease of tea plant. In this study, 240 isolates were isolated from tea plant leaves of 10 provinces in China. Combined with multi-locus (ITS, LSU, RPB2 and TUB2) phylogenetic analysis and morphological characteristics, these isolates were identified as 25 species of six genera in Didymellaceae, including 19 known species Didymellacoffeae-arabicae, D.pomorum, D.segeticola, D.sinensis, Epicoccumcatenisporum, E.dendrobii, E.draconis, E.italicum, E.latusicollum, E.mackenziei, E.oryzae, E.poaceicola, E.rosae, E.sorghinum, E.tobaicum, Neoascochytamortariensis, Paraboeremialitseae, Remotididymellaanemophila and Stagonosporopsiscaricae, of which 15 species were new record species and six novel species, named D.yunnanensis, E.anhuiense, E.jingdongense, E.puerense, N.yunnanensis and N.zhejiangensis. Amongst all isolates, D.segeticola was the most dominant species. Pathogenicity tests on tea plant leaves showed that E.anhuiense had the strongest virulence, while E.puerense had the weakest virulence. Besides, D.pomorum, D.yunnanensis, E.dendrobii, E.italicum, E.jingdongense, E.mackenziei, E.oryzae, E.rosae, E.tobaicum, N.mortariensis, N.yunnanensis, N.zhejiangensis and R.anemophila were non-pathogenic to the tea plant.

The Mitochondrial Distribution and Morphology Family 33 Gene FgMDM33 Is Involved in Autophagy and Pathogenesis in Fusarium graminearum.

The mitochondrial distribution and morphology family 33 gene (MDM33) regulates mitochondrial homeostasis by mediating the mitochondrial fission process in yeast. The wheat head blight Fusarium graminearum contains an FgMdm33 protein that is orthologous to Saccharomyces cerevisiae Mdm33, albeit its function remains unknown. We have reported here the roles of FgMdm33 in regulating fungal morphogenesis, mitochondrial morphology, autophagy, apoptosis, and fungal pathogenicity. The ΔFgmdm33 mutants generated through a homologous recombination strategy in this study exhibited defects in terms of mycelial growth, conidia production, and virulence. Hyphal cells lacking FgMDM33 displayed elongated mitochondria and a dispensable respiratory-deficient growth phenotype, indicating the possible involvement of FgMDM33 in mitochondrial fission. The ΔFgmdm33 mutants displayed a remarkable reduction in the proteolysis of GFP-FgAtg8, whereas the formation of autophagic bodies in the hyphal cells of mutants was recorded under the induction of mitophagy. In addition, the transcriptional expression of the apoptosis-inducing factor 1 gene (FgAIF1) was significantly upregulated in the ΔFgmdm33 mutants. Cumulatively, these results indicate that FgMDM33 is involved in mitochondrial fission, non-selective macroautophagy, and apoptosis and that it regulates fungal growth, conidiation, and pathogenicity of the head blight pathogen.

Phosphocholine cytidylyltransferase MoPct1 is crucial for vegetative growth, conidiation, and appressorium-mediated plant infection by Magnaporthe oryzae.

Phosphatidylcholine (PC) plays crucial biological roles in eukaryotic cells. In Saccharomyces cerevisiae, apart from phosphatidylethanolamine (PE) methylation pathway, PC is also synthesized via CDP-choline pathway. Phosphocholine cytidylyltransferase Pct1 is the rate-limiting enzyme to catalyze the conversion from phosphocholine to CDP-choline in this pathway. Here, we report the identification and functional characterization of an ortholog of the budding yeast PCT1 in Magnaporthe oryzae, named MoPCT1. Targeted gene deletion mutants of MoPCT1 were impaired in vegetative growth, conidiation, appressorium turgor accumulation and cell wall integrity. Also, the mutants were severely compromised in appressorium-mediated penetration, infectious growth and pathogenicity. Western blot analysis revealed that cell autophagy was activated by the deletion of MoPCT1 under nutrient-rich conditions. Moreover, we found several key genes in PE methylation pathway, such as MoCHO2, MoOPI3, and MoPSD2, were significantly up-regulated in the ΔMopct1 mutants, indicating that a pronounced compensation effect exists between the two PC biosynthesis pathways in M. oryzae. Interestingly, in the ΔMopct1 mutants, histone H3 was hypermethylated and expression levels of several methionine cycling-related genes were significantly up-regulated, suggesting that MoPCT1 is involved in histone H3 methylation and methionine metabolism. Taken together, we conclude that the phosphocholine cytidylyltransferase coding gene MoPCT1 plays important roles in vegetative growth, conidiation and appressorium-mediated plant infection by M. oryzae.

Pectate Lyase Genes Abundantly Expressed During the Infection Regulate Morphological Development of Colletotrichum camelliae and CcPEL16 Is Required for Full Virulence to Tea Plants.

Colletotrichum camelliae is the dominant species causing foliar diseases of tea plants (Camellia sinensis) in China. Transcriptome data and reverse transcription-quantitative PCR (qRT-PCR) analysis have demonstrated that the pectate lyase genes in C. camelliae (CcPELs) were significantly upregulated during infectious development on tea plants (cv. Longjing43). To further evaluate the biological functions of CcPELs, we established a polyethylene glycol (PEG)-mediated protoplast transformation system of C. camelliae and generated targeted deletion mutants of seven CcPELs. Phenotypic assays showed that the genes contribute to mycelial growth, conidiation, and appressorium development. The polypeptides encoded by each CcPEL gene contained a predicted N-terminal signal peptide, and a yeast invertase secretion assay suggested that each CcPEL protein could be secreted. Cell death-suppressive activity assays confirmed that all seven CcPELs did not suppress Bax-induced cell death in tobacco leaf cells. However, deletion of CcPEL16 significantly reduced necrotic lesions on tea leaves. Taken together, these results indicated that CcPELs play essential roles in regulating morphological development, and CcPEL16 is required for full virulence in C. camelliae. IMPORTANCE In this study, we first established a PEG-mediated protoplast transformation system of C. camelliae and used it to investigate the biological functions of seven pectate lyase genes (CcPELs) which were abundantly expressed during infection. The results provided insights into the contributions of pectate lyase to mycelial growth, conidial production, appressorium formation, and the pathogenicity of C. camelliae. We also confirmed the secretory function of CcPEL proteins and their role in suppressing Bax-induced cell death. Overall, this study provides an effective method for generating gene-deletion transformants in C. camelliae and broadens our understanding of pectate lyase in regulating morphological development and pathogenicity.

The Paxillin MoPax1 Activates Mitogen-Activated Protein (MAP) Kinase Signaling Pathways and Autophagy through MAP Kinase Activator MoMka1 during Appressorium-Mediated Plant Infection by the Rice Blast Fungus Magnaporthe oryzae.

Paxillin is a focal adhesion-associated protein that functions as an adaptor to recruit diverse cytoskeleton and signaling molecules into a complex and plays a crucial role in several signaling pathways in mammal cells. However, paxillin-mediated signal pathways are largely unknown in phytopathogenic fungi. Previously, Pax1 of Magnaporthe oryzae (MoPax1), a paxillin-like protein, has been identified as a crucial pathogenicity determinant. Here, we report the identification of a mitogen-activated protein (MAP) kinase (MAPK) activator, Mka1 of M. oryzae (MoMka1), that physically interacts with MoPax1. Targeted gene deletion of MoMKA1 resulted in pleiotropic defects in aerial hyphal growth, conidiation, appressorium formation, and pathogenicity in M. oryzae. MoMka1 interacts with Mst50, an adaptor protein of the Mst11-Mst7-Pmk1 and Mck1-Mkk2-Mps1 cascades. Moreover, the phosphorylation levels of both Pmk1 and Mps1 in aerial hyphae of the ΔMomka1 mutant were significantly reduced, indicating that MoMka1 acts upstream from the MAPK pathways. Interestingly, we found that MoMka1 interacts with MoAtg6 and MoAtg13. Deletion of MoMKA1 led to impaired MoAtg13 phosphorylation and enhanced autophagic flux under nutrient-rich conditions, indicating that MoMka1 is required for regulation of autophagy in M. oryzae. Taken together, the paxillin MoPax1 may activate MAP kinase signaling pathways and autophagy through MAP kinase activator MoMka1 and play important roles during appressorium-mediated plant infection by the rice blast fungus. IMPORTANCE Paxillin, as an adaptor recruiting diverse cytoskeleton and signaling molecules into a complex, plays a crucial role in several signaling pathways in mammal cells. However, paxillin-mediated signal pathways are largely unknown in phytopathogenic fungi. Here, we identified that MoMka1 physically interacts with MoPax1. Furthermore, MoMka1 acts upstream from the MAPK pathways through interacting with Mst50, a key protein of the Mst11-Mst7-Pmk1 and Mck1-Mkk2-Mps1 cascades. Meanwhile, MoMka1 interacts with both MoAtg6 and MoAtg13 and controls autophagy initiation by influencing the phosphorylation level of MoAtg13. In summary, we describe a model in which MoPax1 activates MAP kinase signaling pathways and autophagy through MoMka1 during appressorium-mediated plant infection by M. oryzae.

Genome-wide identification of glutathione S-transferase gene family members in tea plant (Camellia sinensis) and their response to environmental stress.

Glutathione S-transferases (GSTs) are ubiquitous enzymes involved in the regulation of plant growth, development, and stress responses. Unfortunately, the comprehensive identification of GSTs in tea plant has not been achieved. In this study, a total of 88 CsGSTs proteins were identified and divided into eight classes, among which the tau class was the largest. Chromosomal localization analysis revealed an uneven distribution of CsGSTs across the tea plant genome. Tandem duplication is the main force driving tea plant CsGSTs expansion. CsGSTs structures and conserved motifs were similar. The analysis of cis-regulatory elements in promoter regions showed that CsGSTs can response to multiple stresses, and that MYB may be involved in the transcriptional regulation of CsGST. RNA-Seq data revealed that the expression of most GSTUs was associated with various stresses, including pathogen and insect attack, cold spells, drought and salt stresses, nitrogen nutrition, bud dormancy, and morphological development, and the expression of these CsGSTs was obviously different in eight tissues. In addition, we proved that CsGSTU19, localized at the nucleus and cell membrane, was involved in tea plant defense against temperature stresses and Co. camelliae infection. These findings provide references for the further functional analysis of GSTs in the future.

Genome-wide functional analysis reveals that autophagy is necessary for growth, sporulation, deoxynivalenol production and virulence in Fusarium graminearum.

Autophagy is a conserved cellular recycling and trafficking pathway in eukaryotic cells and has been reported to be important in the virulence of a number of microbial pathogens. Here, we report genome-wide identification and characterization of autophagy-related genes (ATGs) in the wheat pathogenic fungus Fusarium graminearum. We identified twenty-eight genes associated with the regulation and operation of autophagy in F. graminearum. Using targeted gene deletion, we generated a set of 28 isogenic mutants. Autophagy mutants were classified into two groups by differences in their growth patterns. Radial growth of 18 Group 1 ATG mutants was significantly reduced compared to the wild-type strain PH-1, while 10 Group 2 mutants grew normally. Loss of any of the ATG genes, except FgATG17, prevented the fungus from causing Fusarium head blight disease. Moreover, subsets of autophagy genes were necessary for asexual/sexual differentiation and deoxynivalenol (DON) production, respectively. FgATG1 and FgATG5 were investigated in detail and showed severe defects in autophagy. Taken together, we conclude that autophagy plays a critical role in growth, asexual/sexual sporulation, deoxynivalenol production and virulence in F. graminearum.