Ustilaginoidea virens is an economically important plant pathogen that causes rice false smut, which causes yield reduction and produces mycotoxins in infected grains that pose a serious threat to human and animal health. The target of rapamycin (TOR) signaling pathway acts as a master regular in regulating cell growth and secondary metabolism in fungi. However, little is known about the function of the TOR pathway in regulating fungal development, pathogenicity and mycotoxin biosynthesis in U. virens. Here, we demonstrate that the TOR signaling pathway positively regulates the cell growth, conidiation and pathogenicity in U. virens through the biochemical inhibition of TOR kinases. The inhibition of TOR in U. virens (UvTOR) by rapamycin significantly induces the expression of genes related to mycotoxin biosynthesis, especially that of ustiloxins. Transcriptome analysis under TOR inhibition revealed that the TOR signaling pathway is a regulatory hub that governs U. virens growth and metabolism. A total of 275 differentially expressed genes (DEGs), consisting of 109 up-regulated DEGs and 166 down-regulated DEGs, were identified after rapamycin treatment. The up-regulated DEGs were enriched in amino acid- and acetyl-CoA-related metabolism pathways and the down-regulated DEGs were enriched in carbohydrate- and fatty acid-related metabolism pathways. Collectively, our results provide the first in-depth insight into the TOR signaling pathway in regulating vegetable growth, virulence and mycotoxin biosynthesis in U. virens.

Rice sheath blight (RSB), caused by the pathogenic fungus Rhizoctonia solani, poses a significant threat to global food security. The defense mechanisms employed by rice against RSB are not well understood. In our study, we analyzed the interactions between rice and R. solani by comparing the phenotypic changes, ROS content, and metabolite variations in both tolerant and susceptible rice varieties during the early stages of fungal infection. Notably, there were distinct phenotypic differences in the response to R. solani between the tolerant cultivar Zhengdao22 (ZD) and the susceptible cultivar Xinzhi No.1 (XZ). We observed that the activities of five defense-related enzymes in both tolerant and susceptible cultivars changed dynamically from 0 to 72 h post-infection with R. solani. In particular, the activities of superoxide dismutase and peroxidase were closely associated with resistance to RSB. Metabolomic analysis revealed 825 differentially accumulated metabolites (DAMs) between the tolerant and susceptible varieties, with 493 DAMs responding to R. solani infection. Among these, lipids and lipid-like molecules, organic oxygen compounds, phenylpropanoids and polyketides, organoheterocyclic compounds, and organic acids and their derivatives were the most significantly enriched. One DAM, P-coumaraldehyde, which responded to R. solani infection, was found to effectively inhibit the growth of R. solani, Magnaporthe grisea, and Ustilaginoidea virens. Additionally, multiple metabolic pathways, including amino acid metabolism, carbohydrate metabolism, metabolism of cofactors and vitamins, and metabolism of terpenoids and polyketides, are likely involved in RSB resistance. Our research provides valuable insights into the molecular mechanisms underlying the interaction between rice and R. solani.

Rice blast, caused by rice blast fungus (Magnaporthe oryzae), is a global threat to food security, with up to 50% yield losses. Panicle blast is a severe form of rice blast, and disease responses vary between cultivars with different genotypes. Reactive oxygen species (ROS)-mediated signaling reactions and the phenylpropanoid pathway are important defense mechanisms involved in recognizing and resisting against fungal infection. To understand rice-M. oryzae interactions in resistant and susceptible cultivars, we determined dynamic changes in the activities of five defense-related enzymes in resistant cultivar jingsui 18 and susceptible cultivar jinyuan 899 infected with M. oryzae from 4 to 25 days after infection. We then performed untargeted metabolomics analyses to profile the metabolomes of the cultivars under infected and non-infected conditions. Dynamic changes in the activities of five defense-related enzymes were closely related to panicle blast resistance in rice. Metabolome data analysis identified 634 differentially accumulated metabolites (DAMs) between resistant and susceptible cultivars following infection, potentially explaining differences in disease response between varieties. The most enriched DAMs were associated with lipids and lipid-like molecules, phenylpropanoids and polyketides, organoheterocyclic compounds, organic acids and derivatives, and lignans, neolignans, and related compounds. Multiple metabolic pathways are involved in resistance to panicle blast in rice, including biosynthesis of other secondary metabolites, amino acid metabolism, lipid metabolism, phenylpropanoid biosynthesis, arachidonic acid metabolism, arginine biosynthesis, tyrosine metabolism, tryptophan metabolism, tyrosine and tryptophan biosynthesis, lysine biosynthesis, and oxidative phosphorylation.

Rice (Oryza sativa L.) is one of the world's most crucial food crops, as it currently supports more than half of the world's population. However, the presence of sheath blight (SB) caused by Rhizoctonia solani has become a significant issue for rice agriculture. This disease is responsible for causing severe yield losses each year and is a threat to global food security. The breeding of SB-resistant rice varieties requires a thorough understanding of the molecular mechanisms involved and the exploration of immune genes in rice. To this end, we conducted a screening of rice cultivars for resistance to SB and compared the transcriptome based on RNA-seq between the most tolerant and susceptible cultivars. Our study revealed significant transcriptomic differences between the tolerant cultivar ZhengDao 22 (ZD) and the most susceptible cultivar XinZhi No.1 (XZ) in response to R. solani invasion. Specifically, the tolerant cultivar showed 7066 differentially expressed genes (DEGs), while the susceptible cultivar showed only 60 DEGs. In further analysis, we observed clear differences in gene category between up- and down-regulated expression of genes (uDEGs and dDEGs) based on Gene Ontology (GO) classes in response to infection in the tolerant cultivar ZD, and then identified uDEGs related to cell surface pattern recognition receptors, the Ca2+ ion signaling pathway, and the Mitogen-Activated Protein Kinase (MAPK) cascade that play a positive role against R. solani. In addition, DEGs of the jasmonic acid and ethylene signaling pathways were mainly positively regulated, whereas DEGs of the auxin signaling pathway were mainly negatively regulated. Transcription factors were involved in the immune response as either positive or negative regulators of the response to this pathogen. Furthermore, our results showed that chloroplasts play a crucial role and that reduced photosynthetic capacity is a critical feature of this response. The results of this research have important implications for better characterization of the molecular mechanism of SB resistance and for the development of resistant cultivars through molecular breeding methods.

Piriformospora indica, a plant root-colonizing basidiomycete fungus, exhibits strong growth-promoting activity in symbiosis with a broad range of plants. Here, we report the potential of P. indica to improve growth, yield, and disease resistance in wheat in the field. In the present study, P. indica successfully colonized wheat through chlamydospores and formed dense mycelial networks that covered roots. Plants subjected to the seed soaking (SS) treatment with P. indica chlamydospore suspensions enhanced tillering 2.28-fold compared to the non-inoculated wheat in the tillering stage. In addition, P. indica colonization promoted vegetative growth significantly during the three-leaf, tillering, and jointing stages. Moreover, the P. indica-SS-treatment enhanced wheat yield by 16.37 ± 1.63%, by increasing grains per ear and panicle weight and decreased damage to wheat shoot and root architecture markedly, with high field control effects against Fusarium pseudograminearum (81.59 ± 1.32%), Bipolaris sorokiniana (82.19 ± 1.59%), and Rhizoctonia cerealis (75.98 ± 1.36%). Most of the primary metabolites, such as amino acids, nucleotides, and lipids, involved in vegetative reproduction were increased in P. indica-SS-treatment plants, whereas secondary metabolites, such as terpenoids, polyketides, and alkaloids, decreased following P. indica inoculation. The up-regulated processes of protein, carbohydrate, and lipid metabolism indicated that P. indica colonization increased growth, yield, and disease resistance via the acceleration of plant primary metabolism. In conclusion, P. indica improved morphological, physiological, and metabolic substance levels, and further promoted its growth, yield, and disease resistance in wheat.

为培育健壮的黄瓜幼苗,解决黄瓜冬春季穴盘育苗存在的幼苗徒长、质量差等问题,本试验采用药液浸种的方法,研究了植物生长调节剂1.2％吲哚丁酸水剂、5％萘乙酸可溶液剂、5％吲哚丁酸·萘乙酸可溶液剂和0.01％28-高芸薹素内酯可溶液剂对黄瓜幼苗生长的影响.试验结果表明,1.2％吲哚丁酸水剂10 mg/kg在25℃下浸种48 h后,能显著促进黄瓜根系生长,提高幼苗壮苗指数,壮苗指数增加率为39.73％.本研究为培育优质黄瓜秧苗提供了参考依据.

为了培育健康的水稻秧苗,提高水稻秧苗素质,本试验以'津育粳22'为试材,应用药液浸种的方法,研究了 4种植物生长调节剂不同浓度和不同浸种时间对水稻种子萌发和对水稻秧苗素质的影响,试验药剂分别为5％吲哚丁酸·萘乙酸可溶液剂(A)、1％吲哚丁酸·诱抗素可溶液剂(B)、0.25％S-诱抗素水剂(C)、0.136％赤·吲乙·芸可湿性粉剂(D).试验结果表明,20 mg/kg药剂A浸种24 h和0.4 mg/kg药剂C浸种24h和48h后,水稻种子发芽势高于清水对照,各药剂处理对种子发芽指数和发芽率影响不明显.水稻种子25℃药液浸种24 h后,筛选出20 mg/kg药剂A、10 mg/kg药剂B、0.4 mg/kg药剂C和1000倍液药剂D能显著提高水稻秧苗的壮苗指数,壮苗指数增加率分别为19.14％、17.68％、34.55％和23.80％.综上,生产中推荐使用20 mg/kg 5％吲哚丁酸·萘乙酸可溶液剂、10 mg/kg 1％吲哚丁酸·诱抗素可溶液剂、0.4 mg/kg 0.25％S-诱抗素水剂和1000倍液0.136％赤·吲乙·芸可湿性粉剂浸种24 h,可提高种子出苗率和秧苗的壮苗指数.

近年来,水稻穗腐病在天津地区发生较重,成为影响水稻产量和品质的重要病害之一.本试验连续两年对天津地区水稻主产区穗腐病危害进行调查、病原菌分离鉴定,并采用生长速率抑制法测定病原菌对 9种杀菌剂的敏感性.病原菌分离鉴定结果显示,引起天津地区水稻穗腐病的病原菌为稻黑孢霉(Nigrospora oryzae).药剂敏感性测定结果显示,95％咯菌腈和 95.3％丙环唑对稻黑孢霉抑菌效果最好,2020 年EC50值分别为 0.2776、1.3102 μg/mL,2021 年EC50值分别为 0.5171、2.0188 μg/mL;80％代森锰锌可湿性粉剂对两年菌株的抑制效果差异较大,对 2020 年菌株EC50值为 8.0151 μg/mL,对 2021 年菌株的EC50值为 24.6704 μg/mL.75％三环唑对该病原菌无抑制作用,生产上不推荐使用.本研究明确了天津地区水稻穗腐病的致病菌株并筛选了高效抑菌药剂,为生产中该病害的防治提供了参考.

黑粉菌素(ustilaginoidins)是由稻曲菌产生的一种聚酮类真菌毒素.稻曲菌侵染水稻穗部引发稻曲病,不仅导致水稻产量下降,还存在感病籽粒真菌毒素污染的问题,严重威胁我国的粮食安全.近年来,随着稻曲菌全基因组测序工作的完成,黑粉菌素的生物合成基因也逐渐被揭示.研究表明:黑粉菌素生物合成基因簇是由UvPKS1(UV_2086)所在的基因簇负责合成,该基因簇全长49.7 kb,共包含14个基因,命名为ugs基因簇.就近年来黑粉菌素的分离与鉴定、生物活性分析以及检测方法等方面进行综述,并着重对其生物合成路径进行介绍,为进一步解析稻曲菌黑粉菌素生物合成的调控机制以及制定控制毒素污染的策略提供研究基础.

基于极端表型单株高通量测序的定位方法QTL-seq已成为植物QTL分析的一种主要方法.继QTL-seq分析后,对目标QTL定位区间进行分子标记开发时,由于目标区间大,所含变异位点多,特定区间的分子标记开发仍是一件较繁琐的事.为提高特定区间分子标记开发的效率,本研究建立了基于高通量测序数据基础的特定脚本程序,可简单快速地完成水稻基因组任意区间的InDel标记开发.本研究开发了来自7个不同作图群体和染色体区间的有8 bp以上片段长度差异的InDel标记708个,平均每17.6 kb有1个InDel标记;对95个标记进行试验验证,总体多态频率为63％.本研究建立的方法在水稻及其他已测序的植物重要农艺性状控制QTL的分子标记辅助育种、精细定位和图位克隆中有重要应用价值.

为明确人工接种与自然诱发对水稻稻瘟病的鉴定结果,将65份水稻材料分别种植于人工接种病圃和自然诱发病圃,通过不同的稻瘟病接种方式获得每个品种对稻瘟病抗性的综合指数及表型数据,2个地点对比结果显示:人工接种方式对于每个品种、每个稻穗条件一样,发病均匀,重复性好,能够比较不同品种之间的抗性差异,而自然诱发方式,受生长期复杂环境因素影响,有的水稻品种靠近感病对照(蒙古稻)位置的穗颈瘟发病重,远离蒙古稻的稻穗发病轻或不发病,病原菌分布不均匀,造成个体间重复性差,结果差异大;人工接种病圃所用病原菌为上一年田间病样分离获得的,不能代表当年病原菌的类型,具有滞后性.因此,建议将2种接种方式综合起来,不管是哪一种结果,只要水稻品种表现感病,说明该品种对稻瘟病存在着抗性风险,同时也应该加强同一地区稻瘟病菌生理小种的监测,进一步揭示表型差异的原因.

为了解天津小麦茎基腐病的发生情况,本试验分别在天津市蓟州区、宝坻区、武清区、静海区和北辰区5个小麦主栽区采集茎基腐病害样品33份,分离真菌菌株204个.经致病性测定、形态学观察及对rDNA-ITS的分子检测,最终确定为5类病原菌,分别为小麦根腐离蠕孢(Bipolaris sorkiniana)、假禾谷镰刀菌(紫红色、黄色,Fusarium pseudograminearum)、燕麦镰刀菌(F.avenaceum)和木贼镰刀菌(F.equiseti),优势菌株为假禾谷镰刀菌,占分离病原菌总数的74.5％.5类病原菌对8种杀菌剂的敏感性测定结果表明,咯菌腈、丙硫菌唑和咪鲜胺对蠕孢菌的抑制效果最好,咯菌腈、咪鲜胺和多菌灵对镰刀菌的抑制效果最好.

主要介绍了植物生长调节剂芸苔素内酯、S-诱抗素、调环酸钙、赤霉酸及一些复配制剂的作用方式和在水稻上的应用现状及研究进展,并阐明了植物生长调节剂在施用过程中的注意事项,旨在为水稻科学合理应用植物生长调节剂,促进水稻的优质高产提供科学依据.

本文描述了天津地区水稻纹枯病的病原及危害症状,并针对该病进行了水稻抗病品种筛选及化学药剂防治效果的比较.结果 表明:水稻不同品种对纹枯病抗性存在着较大差异,通过人工接种鉴定可以获得抗性较好的品种,此外三唑类和苯并咪唑类化学药剂对水稻纹枯病有较好的防治效果,本研究总结了最佳的化学药剂种类、施用时期和使用方法,为该病的防治提供了借鉴.

本试验利用中国7个鉴别寄主对分离的20个单孢纯培养菌株进行生理小种鉴定,并对稻瘟病的防控技术进行研究.结果表明:引起天津地区稻瘟病的生理小种有ZG1、ZD1、ZC3、ZB17四种;24个水稻品种中,津垦63、津稻328等6个品种对稻瘟病表现中抗;250 g/L嘧菌酯悬浮剂、25％咪鲜胺水乳剂、430 g/L戊唑醇悬浮剂、40％稻瘟灵乳油对稻瘟病的防治效果较好.

本研究利用平板筛选法,从转座子TnYLB-1转化的解淀粉芽孢杆菌Bs-18的突变体文库中筛选到生防作用发生明显变化的3株突变株.以这3株突变株为材料,通过反向PCR技术对突变体中转座子插入位点的侧翼序列进行BLAST比对分析,发现它们与野生芽孢杆菌的芽孢形成、细胞分离、细胞的一系列代谢活动等有关.

针对天津地区水稻苗期病害发生的种类、病原、危害症状,以及近年来生产上出现的化学药剂防效降低和安全性差等问题,笔者选取8种针对水稻苗期病害使用频率较高的化学药剂进行室内毒力测定,明确了药剂的防治效果,给出了推荐使用药剂的种类及使用方法,以指导农民精准对靶施药,提高防治效果,减少化学农药用量.

[目的]本文研究了在天津市植保所武清创新基地温室番茄上一种叶部病害,明确了引起该病病原菌种类,并筛选出防治该病的有效药剂.[方法]运用形态学与对病菌核糖体DNA的ITS区分析相结合的方法对引起该病的病原进行鉴定,采用平皿法测定了9种杀菌剂对该病原菌的室内抑菌效果.[结果]病菌的形态学特征与已报道的引起番茄漆斑病的病原露湿漆斑菌Myrothecium roridum的形态学特征相一致,病菌ITS区序列与M.roridum的ITS区序列相似性最高,达到99％,进一步确定引起番茄叶斑病的病菌为露湿漆斑菌M.roridum.室内药剂筛选结果表明:41.7％氟吡菌酰胺SC、250 g/L嘧菌酯SC、250 g/L吡唑醚菌酯EC和80％多菌灵WP对该菌菌丝抑制效果最好,其EC50值分别为0.094、0.781、1.041和1.396 μg/mL.[结论]以上4种药剂均可作为防治番茄漆斑病的有效药剂.

Bacillus amyloliquefaciens Bs-18 is a biocontrol strains against cucumber powdery mildew with significant control effect. In this paper, the mutant library of Bs-18 was constructed with the shuttle plasmid pMarA carrying transposon TnYLB-1 by the electric shock method to deeply study the molecular mechanism of the biocontrol strain. Through screening transpositional temperature and time, the maximum transpositional success rate was obtained after induced at 50℃ for 16 hours. The mutants were verified by PCR. The construction of Bs-18 mutant library laid a foundation for further study on its biocontrol function genes and mechanism.

To obtain antagonistic bacteria for biocontrol of cucumber powdery mildew , 692 bacterial strains were isolated from different greenhouse soil samples .The strain Bs-18 , which had good inhibitory effect on cucumber powdery mildew with the control effect of 82 .22%, was screened out using plate confrontation method and pot test .Based on the morphological characteristics , physicochemical properties and 16 S rDNA sequence analysis , the strain Bs-18 was identified as Bacillus amyloliquefaciens.