Proteomic analysis of pathogen-responsive proteins from maize stem apoplast triggered by Fusarium verticillioides

During the attack of a pathogen, a variety of defense-associated proteins are released by the host plant in the apoplast to impede the perceived attack. This study utilized the mass spectrometry(LC-MS/MS) and label-free quantification method to analyze the apoplastic fluid(APF) from maize stalk and identified the proteins responsive to the Fusarium verticillioides infection. We have identified 742 proteins, and among these, 119 proteins were differentially accumulated(DAPs), i.e., 35 up-regulate...     

Grain proteomic analysis reveals central stress responsive proteins caused by wheat-Haynaldia villosa 6VS/6AL translocation

Haynaldia villosa (2n=14, VV), a wild grass of the subtribe Triticeae, serves as potential gene resources for wheat genetic improvement. In this study, the proteome characterization during grain development of Yangmai 5 and Yangmai 5-H. villosa 6VS/6AL translocation line was investigated by a comparative proteomic approach. Two-dimensional electrophoresis identified 81 differentially accumulated proteins (DAPs) during five grain developmental stages in wheat-H. villosa translocation line. These proteins were mainly involved in stress defense, storage protein, energy metabolism, protein metabolism and folding, carbon metabolism, nitrogen metabolism, and starch metabolism. In particular, 6VS/6AL translocation led to significant upregulation of 36 DAPs and specific expression of 11 DAPs such as chitinase, thaumatin-like proteins, glutathione transferase, α-amylase inhibitor, heat shock proteins, and betaine aldehyde dehydrogenase. These proteins mainly involved in biotic and abiotic stress responses. Further analysis found that the upstream 1 500 promoter regions of these stress-responsive DAP genes contained multiple high-frequency cis-acting elements related to stress defense such as abscisic acid response element ABRE, methyl jasmonate (MeJA)-response element TGACG-motif and CGTCA-motif involved in oxidative stress and antioxidant response element (ARE). RNA-seq and RT-qPCR analyses revealed the high expression of these stress-defensive DAP genes in the developing grains, particularly at the early-middle grain filling stages. Our results demonstrated that 6VS chromosome of H. villosa contains abundant stress-defensive proteins that have potential values for wheat genetic improvement.     

花魔芋响应软腐病菌侵染初期的转录组分析

为探讨花魔芋抵御软腐病害的分子机制,分别以染病初期和健康的花魔芋球茎为材料进行转录组测序。结果表明,健康和染病初期花魔芋两组出现3222个差异表达基因,其中2660个基因上调表达,562个基因下调表达,差异表达基因主要涉及细胞组分、生物学过程及分子功能等生理生化过程。表达量上调和下调最大的前10个基因包含编码MiAMP1抗菌蛋白、热激蛋白、胰蛋白酶与蛋白酶抑制剂、胰凝乳蛋白酶抑制剂等与抗病相关的基因。GO功能分类和KEGG通路分析表明,类黄酮和苯丙烷类物质在花魔芋抵御软腐病菌侵染初期发挥重要作用。值得关注的是,硒化合物代谢、维生素B6代谢、类黄酮生物合成、N-聚糖生物合成及链霉素生物合成通路等抗病相关的差异表达基因在花魔芋染病初期全部或大部分受诱导表达。利用高通量测序获得大量花魔芋转录组信息,有助于挖掘与花魔芋抗软腐病相关的关键基因,也为魔芋抗病分子育种提供理论参考。     

Evolutionary analysis of plant jacalin-related lectins (JRLs) family and expression of rice JRLs in response to Magnaporthe oryzae

Jacalin-related lectins (JRLs) are widely distributed carbohydrate-binding proteins in the plant kingdom, which play key roles in development and pathogen defense. In this study, we profiled evolutionary trajectory of JRLs family in 30 plant species and identified domain diversification and recombination leading to different responsive patterns of JRLs in rice during defense against rice blast. All of 30 plant species analyzed in our study have two types of JRLs by containing either a single jacalin or repeated jacalin domains, while chimeric jacalins exist in more than half of the species, especially in the Poaceae family. Moreover, Poaceae species have evolved two types of unique chimeric JRLs by fusing the jacalin domain(s) with dirigent or NB_ARC domain, some of which positively regulate plant immunity. Seven Poaceae-specific JRLs are found in the rice genome. We further found expression of rice JRLs, including four Poaceae-specific JRLs, are induced by Magnaporthe oryzae infections at either early or late infection stages. Overall, the results present the evolutionary trajectory of JRLs in plant and highlight essential roles of Poaceae specific JRLs against pathogen attacks in rice.     

Expression Comparisons of Pathogenesis-Related (PR) Genes in Wheat in Response to Infection/Infestation by Fusarium,Yellow dwarf virus (YDV) Aphid-Transmitted and Hessian Fly

Expression profiles of ten pathogenesis-related (PR) genes during plant defense against Fusarium, Yellow dwarf virus (YDV) aphid-transmitted and Hessian fly (Hf) were compared temporally in both resistant and susceptible genotypes following pathogen infection or insect infestation. Quantitative real-time PCR (qRT-PCR) revealed that PR1, PR2, PR3, PR5, PR6, PR8, PR9, and PR15 appeared to be induced or suppressed independently in response to Fusarium, YDV aphid-transmitted or Hf during the interactions. The PR gene(s) essential to defense against one organism may play little or no role in defense against another pathogen or pest, suggesting the alternative mechanisms may be involved in different interactions of wheat-Fusarium, wheat-YDV aphid-transmitted and wheat-Hf. However, strong up- or down-regulation of PR12 and PR14 encoding low molecular membrane acting protein, defensin and lipid transfer protein (LTP), respectively, had been detected after either pathogen infection or insect infestation, therefore showed broad responses to pathogens and insects. It was postulated that low molecular proteins such as defensins and LTPs might play a role in the early stages of pathogenesis in the signaling process that informs plants about the attack from biotic stresses. In addition, a synergistic action between different PR genes might exist in plants to defense certain pathogens and insects on the basis of comprehensive expression profiling of various pathogenesis-related genes revealed by qRT-PCR in this study.     

丙硫菌唑对水稻纹枯病菌的生物活性研究

丙硫菌唑是目前广泛应用的三唑类广谱杀菌剂。为了明确其对水稻纹枯病菌的生物活性,采用生物测定的方法研究了丙硫菌唑对水稻纹枯病菌的抑菌活性,应用生理生化和分子生物学方法研究了丙硫菌唑对水稻纹枯病菌的可溶性蛋白合成、麦角甾醇合成、 DNA 合成、菌丝脂质过氧化程度、菌丝细胞膜通透性以及水稻防御酶活性的影响。通过田间药效试验研究了其防治纹枯病效果及对水稻的安全性。结果表明,丙硫菌唑对94株水稻纹枯病菌有较高的抑菌活性,平均EC₅₀值为（1.062 9 ± 0.795 9）mg·L^-1。没有出现敏感性下降的抗药性群体,可以釆用菌株的平均EC₅₀值作为水稻纹枯病菌对丙硫菌唑的敏感性基线。丙硫菌唑导致病菌麦角甾醇含量降低,菌丝细胞渗透压、菌丝脂质过氧化程度升高,DNA含量和可溶性蛋白含量随降低。丙硫菌唑使POD、CAT、SOD和PAL 4个植物基础防御酶活性升高,具有一定诱导抗病性。田间试验结果显示4.8×10⁵ mg·L^-1丙硫菌唑悬浮剂,每亩施用剂量为25、30和35 mL时,对水稻纹枯病的防治效果分别达90.40%、96.29%和98.17%,与对照试剂噻呋酰胺的防效相当,且对水稻生长安全。     

玉米幼根接种禾谷镰刀菌后的转录组分析

为研究禾谷镰刀菌侵染后玉米幼根内转录组的变化情况,利用RNAseq对禾谷镰刀菌接种后6和18h的感病玉米自交系Y331分别进行转录组测序,分析接种后玉米幼根内差异表达的基因。结果表明:接种禾谷镰刀菌后,玉米幼根内共有5 153个基因差异表达;在接种后上调表达的聚类中,多种抗病过程相关的基因显著富集,包括苯丙烷类次生代谢物质合成过程的基因以及植物激素水杨酸(Salicylic acid,SA)、茉莉酸(Jasmonic acid,JA)和乙烯(Ethylene,ET)合成、响应及信号介导途径的基因;在下调表达的聚类中,植物生长发育、基础物质和能量代谢相关过程的基因显著富集。进一步分析发现:ET相关过程的基因在聚类1和聚类6中显著富集,均在接种后6h前上调表达;苯丙烷类次生代谢物合成途径相关基因和镰刀烯醇毒素(Deoxynivalenol,DON)解毒相关基因在接种后上调表达。研究表明,SA、JA/ET、苯丙烷类次生代谢物和DON解毒基因在玉米和禾谷镰刀菌互作中发挥重要作用。     

Genome-wide identification and analysis of the regulation wheat DnaJ family genes following wheat yellow mosaic virus infection

The co-chaperone DnaJ plays an important role in protein folding and regulation of various physiological activities, and participates in several pathological processes. DnaJ has been extensively studied in many species including humans,drosophila, mushrooms, tomatoes, and Arabidopsis. However, few studies have examined the role of DnaJ in wheat(Triticum aestivum), and the interaction mechanism between TaDnaJs and plant viruses. Here, we identified 236 TaDnaJs and performed a comprehensive genome...     

Two farnesyl pyrophosphate synthases,GhFPS1–2, in Gossypium hirsutum are involved in the biosynthesis of farnesol to attract parasitoid wasps

Sesquiterpenoids play an import role in the direct or indirect defense of plants. Farnesyl pyrophosphate synthases(FPSs) catalyze the biosynthesis of farnesyl pyrophosphate, which is a key precursor of farnesol and(E)-β-farnesene. In the current study, two FPS genes in Gossypium hirsutum, GhFPS1 and GhFPS2, were heterologously cloned and functionally characterized in a greenhouse setting. The open reading frames for full-length GhFPS1 and GhFPS2 were each 1 029 nucleotides, and encoded two proteins of 342 amino acids with molecular weights of 39.4 kDa. The deduced amino acid sequences of GhFPS1–2 showed high identity to FPSs of other plants. Quantitative real-time PCR analysis revealed that GhFPS1 and GhFPS2 were highly expressed in G. hirsutum leaves, and were upregulated in methyl jasmonate(MeJA)-, methyl salicylate(MeSA)-and aphid infestation-treated cotton plants. The recombinant proteins of either GhFPS1 or GhFPS2 plus calf intestinal alkaline phosphatase could convert geranyl diphosphate(GPP) or isopentenyl diphosphate(IPP) to one major product, farnesol. Moreover, in electrophysiological response and Y-tube olfactometer assays, farnesol showed obvious attractiveness to female Aphidius gifuensis, which is an important parasitic wasp of aphids. Our findings suggest that two GhFPSs are involved in farnesol biosynthesis and they play a crucial role in indirect defense of cotton against aphid infestation.     

Proteomics Identification of Differentially Expressed Leaf Proteins in Response to Setosphaeria turcica Infection in Resistant Maize

Northern corn leaf blight （NCLB）, caused by the heterothallic ascomycete fungus Setosphaeria turcica, is a destructive foliar disease of maize and represents a serious threat to maize production worldwide. A comparative proteomic study was conducted to explore the molecular mechanisms underlying the defense responses of the maize resistant line A619 Ht2 to S. turcica race 13. Leaf proteins were extracted from mock and S. turcica-infected leaves after inoculated for 72 h and analyzed for differentially expressed proteins using two-dimensional electrophoresis and mass spectrometry identification. 137 proteins showed reproducible differences in abundance by more than 2-fold at least, including 50 up-regulated proteins and 87 down-regulated proteins. 48 protein spots were successfully identified by MS analysis, which included 10 unique, 6 up-regulated, 20 down-regulated and 12 disappeared protein spots. These identified proteins were classified into 9 functional groups and involved in multiple functions, particularly in energy metabolism （46%）, protein destination and storage （12%）, and disease defense （18%）. Some defense-related proteins were upregulated such as 13-glucosidase, SOD, polyamines oxidase, HSC 70 and PPIases; while the expressions of photosynthesis- and metabolism-related proteins were down-regulated, by inoculation with S. turcica. The results indicated that a complex regulatory network was functioned in interaction between the resistant line A619 Ht2 and S. turcica. The resistance processes of A619 Ht2 mainly resided on directly releasing defense proteins, modulation of primary metabolism, affecting photosyntesis and carbohydrate metabolism.     

Identification of field isolates of Rhizoctonia solani to detect quantitative resistance in rice under greenhouse conditions

The rates of in vitro hyphal growth of Rhizoctonia solani isolates, and their pathogenicity were evaluated to identify R. solani isolates that are suitable to detect quantitative resistance in rice. The isolates of R. solani were purified from the infected rice and two grass species in Arkansas over three years. Among 200 Rhizoctonia-like isolates, 102 isolates were identified as R. solani, and confirmed using a ribosomal DNA internal transcribed spacers’ marker. The rates of in vitro hyphal growth of the 102 R. solani isolates ranged from 1.17 to 1.89 mm/h, of which only 13.7% were significantly different from each other. The rates of in vitro hyphal growth of eight selected isolates were correlated with lesion lengths (r = 0.86 at P = 0.005 9 and r = 0.93 at P = 0.000 1) on the detached leaves of rice cultivars of Jasmine 85 (resistant) and M202 (susceptible), respectively. The eight isolates were selected based on the mean values of the maximal (1.89), median (1.54) and minimal (1.17) rates of hyphal growth. Two isolates that consistently exhibited significant differences in the rates of the hyphal growth were selected to examine the aggressiveness of isolates in micro-chambers. Using a micro-chamber, the slow growing isolates separated susceptible cultivars from moderately resistant cultivars better than the fast growing isolates. In contrast, the differences in disease reactions between both R. solani isolates were undetected using a standard field evaluation method. We suggest that the slow growing isolates are more useful than the fast growing isolates for detecting quantitative resistance with the micro-chamber method.     

Potassium sulphate induces resistance of rice against the root-knot nematode Meloidogynegraminicola

Potassium (K), an important nutrient element, can improve the stress resistance/tolerance of crops. The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield. However, data on K₂SO₄ induced rice resistance against the root-knot nematode Meloidogynegraminicola are still lacking. In this work, K₂SO₄ treatment reduced galls and nematodes in rice plants and delayed the development of nematodes. Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites, such an effect is achieved by rapidly priming hydrogen peroxide (H₂O₂) accumulation and increasing callose deposition. Meanwhile, galls and nematodes in rice roots were more in the potassium channel OsAKT1 and transporter OsHAK5 gene-deficient plants than in wild-type, while the K₂SO₄-induced resistance showed weaker in the defective plants. In addition, during the process of nematode infection, the expression of jasmonic acid (JA)/ethylene (ET)/brassinolide (BR) signaling pathway-related genes and pathogenesis-related (PR) genes OsPR1a/OsPR1b was up-regulated in rice after K₂SO₄ treatment. In conclusion, K₂SO₄ induced rice resistance against M. graminicola. The mechanism of inducing resistance was to prime the basal defense and required the participation of the K⁺ channel and transporter in rice. These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.     

动物双歧杆菌AD011暴露外表面蛋白的种类和功能分析

[目的]分析动物双歧杆菌AD011暴露外表面蛋白的种类和功能,有助于了解该菌株的各项生理功能以及为探讨该菌与宿主相互作用的分子机制奠定基础。[方法]以动物双歧杆菌AD011基因组序列为研究对象,采用Inmembrane方法和COG功能数据库对预测的外表面蛋白进行功能注释和聚类分析。[结果]AD011菌体暴露外表面蛋白数目为193个,包括11个细胞壁蛋白、20个脂蛋白、暴露外表面的膜蛋白140个、22个细胞外蛋白。AD011外表面蛋白的功能分析结果显示,193个外表面蛋白中,含有较大比例的蛋白没有功能注释(78个),115个蛋白具有COG功能注释。在有功能注释的蛋白中,所占比例较大的是氨基酸转运与代谢(16个),无机离子转运与代谢(14个),细胞壁、细胞膜生物合成(13个),碳水化合物转运与代谢(10个),防御机制(10个)等有关蛋白。[结论]AD011菌体外表面蛋白与营养物质的吸收和转运,细胞壁、细胞膜生物合成,防御机制有关。     

生防菌长枝木霉菌株T6及其代谢产物对立枯丝核菌拮抗作用

为了开发对立枯丝核菌（Rhizoctonia solani）具有较好拮抗作用的生防制剂,采用对峙培养法、含药培养基法和显微观察法,测定生防菌长枝木霉(Trichoderma longibrachiatum）菌株T6及其代谢产物对立枯丝核菌的抑制作用活性,初步探究长枝木霉菌株T6的作用机制。结果表明,长枝木霉菌株T6对立枯丝核菌生长具有显著的抑制作用,对峙培养5 d时菌株T6不仅对立枯丝核菌营养生长抑制率为66.50%,而且对其菌丝具有明显重寄生作用。菌株T6发酵液及其代谢产物对立枯丝核菌营养生长也具有显著的抑制效果,培养4 d时其对立枯丝核菌的生长抑制率分别为72.29%和71.91%。因此,长枝木霉菌株T6对立枯丝核菌具有显著的拮抗作用,主要通过对病原菌的重寄生作用及其代谢产物发挥拮抗作用。     

Current progress on genetic interactions of rice with rice blast and sheath blight fungi

Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Currently, dozens of rice resistance (R) genes against specific races of the blast fungus have been described. Among them, ten were molecularly characterized and some were widely used for breeding for genetic resistance. The Pi-ta gene was one of the best characterized rice R genes. Following the elucidation of its molecular structure, interaction, distribution, and evolution, user friendly DNA markers were developed from portions of the cloned genes to facilitate the incorporations of the Pi-ta mediated resistance into improved rice varieties using marker assisted selection (MAS). However, rice blast is still a major threat for stable rice production because of race change mutations occurring in rice fields, which often overcome added resistance based on single R genes, and these virulent races of M. oryzae pose a continued challenge for blast control. For sheath blight, progress has been made on the exploration of novel sources of resistance from wild rice relatives and indica rice cultivars. A major quantitative trait locus (QTL), named qSB9-2, was recently verified in several mapping populations with different phenotyping methods, including greenhouse methods. The ability to identify qSB9-2 using greenhouse methods should accelerate the efforts on the qSB9-2 fine mapping and positional cloning.     

Physiology and defense responses of wheat to the infestation of different cereal aphids

Cereal aphids are major insect pests of wheat, which cause significant damages to wheat production. Previous studies mainly focused on the resistance of different wheat varieties to one specific aphid species. However, reports on the physiology and defense responses of wheat to different cereal aphids are basically lacking. In this work, we studied the feeding behavior of three cereal aphids: the grain aphid, Sitobion avenae(Fabricius), the greenbugs, Schizaphis graminum(Rondani), and the bird cherry-oat aphid, Rhopalosiphum padi(Linnaeus) on winter wheat, and the physiology and defense responses of wheat to the infestation of these cereal aphids with focus on how these cereal aphids utilize divergent strategies to optimize their nutrition requirement from wheat leaves. Our results indicated that S. graminum and R. padi were better adapted to penetrating phloem tissue and to collect more nutrition than S. avenae. The harm on wheat physiology committed by S. graminum and R. padi was severer than that by S. avenae, through reducing chlorophyll concentration and interfering metabolism genes. Furthermore, cereal aphids manipulated the plant nutrition metabolism by increasing the relative concentration of major amino acids and percentage of essential amino acids. In addition, different cereal aphids triggered specific defense response in wheat. All of these results suggested that different cereal aphids utilize divergent strategies to change the physiological and defense responses of their host plants in order to optimize their nutrition absorption and requirement. These findings not only extend our current knowledge on the insect–plant interactions but also provide useful clues to develop novel biotechnological strategies for enhancing the resistance and tolerance of crop plants against phloem-feeding insects.     

Tomato SlPti5 plays a regulative role in the plant immune response against Botrytis cinerea through modulation of ROS system and hormone pathways

While SlPti5 has been shown to play a crucial role in the regulation of antagonistic genes in Solanum lycopersicum and Arabidopsis against pathogen infection, there have been no comprehensive studies on the effects of SlPti5 on the regulatory response mechanism of reactive oxygen species(ROS) system and hormone pathways during growth and disease resistance of tomato plants. Here, we investigated the function of SlPti5 in the defense response of tomato against Botrytis cinerea utilizing a virus-i...