我国水稻白叶枯病和条斑病发生与防控研究进展

培育和种植抗病品种和研发新型绿色杀菌剂是防治水稻白叶枯病和条斑病的有效措施。最近几年有关稻黄单胞菌Xanthomonas oryzae致病效应蛋白调控水稻抗(感)病性研究取得了突破性进展, 为水稻抗性品种培育提供了新思路、新策略。本文对稻黄单胞菌-水稻互作系统中已知的TALE效应蛋白与水稻抗(感)病基因(R 或 S)的对应关系进行了归纳, 就tal基因与水稻R或S基因的协同进化进行了分析, 结合生物农药和高效低毒杀菌剂的应用现状, 提出了我国水稻白叶枯病和水稻条斑病绿色防控关键策略。     

米根霉菌丝球半连续发酵产乳酸的工艺研究

采用单因素试验和正交试验设计,以乳酸质量浓度及菌丝形态为考察指标,对米根霉首批发酵培养基及补料培养基进行优化,得到适于米根霉半连续发酵的培养基,建立了米根霉半连续发酵工艺,并进行米根霉半连续发酵产乳酸的稳定性试验.得到首批培养基参数为葡萄糖120 g/L,(NH_4)2SO_4 2 g/L,NaH_2PO_4 0.16 g/L,KH_2PO_4 0.14g/L,MgSO_4·7H_2O 0.2 g/L,ZnSO_4·7H_2O 0.22 g/L,CaCO_3 60g/L;补料培养基参数为葡萄糖100g/L,(NH_4)_2SO_4 2 g/L,KH_2PO_4 0.1 g/L,ZnSO_4·7H_2O 0.33 g/L,MgSO_4·7H_2O 0.15 g/L,CaCO_3 50 g/L,摇瓶重复稳定发酵30批次,罐发酵重复稳定发酵20批次,葡萄糖转化率最高达到86%.     

Integrated pest management programme for cereal blast fungus Magnaporthe oryzae

Magnaporthe oryzae, the causal agent of blast diseases, is a destructive filamentous fungus that infects many plants including most economically important food crops, rice, wheat, pearl millet and finger millet. Magnaporthe oryzae has numerous pathotypes because of its high host-specificity in the field. The Oryza pathotype (MoO) of M. oryzae is the most devastating pathogen of rice, causing 10–30% yield loss in the world. On the other hand, the Triticum pathotype (MoT) causes blast disease in wheat, which is now a serious threat to wheat production in some South American countries, Bangladesh and Zambia. Because of low fungicide efficacy against the blast diseases and lack of availability of resistant varieties, control of rice and wheat blast diseases is difficult. Therefore, an integrated management programme should be adopted to control these two diseases in the field. Here, we introduced and summarized the classification, geographical distribution, host range, disease symptoms, biology and ecology, economic impact, and integrated pest management (IPM) programme of both rice and wheat blast diseases.     

黑龙江省和海南省PWL基因家族在稻瘟病菌中的分布及变异

【目的】了解不同稻瘟病菌（Magnaporthe oryzae）菌株群体中PWL基因家族的分布和变异特征，为研究不同稻瘟病菌群体的遗传多样性及特异性提供依据。【方法】通过参考NCBI中公布的无毒基因序列分别对PWL基因家族的启动子区和CDS区设计特异性引物共8对，对2020年采自黑龙江省和海南省不同地区的397个稻瘟病菌单孢分离菌株提取DNA，进行无毒基因的PCR扩增并通过琼脂糖凝胶电泳检测，从检测结果中分别选取囊括不同地区的代表菌株对扩增片段进行测序分析。测序结果与NCBI中相应无毒基因启动子区和CDS区的碱基与氨基酸序列进行比较分析。【结果】在PCR电泳检测结果中，PWL1在所有菌株中均未检测出；PWL2、PWL3和PWL4在黑龙江省和海南省中均扩增出特异性片段，说明这3种基因在两省中均有分布并分别存在不同的分布频率与变异类型。其中PWL2在黑龙江省和海南省中分布频率最高，分别为98.14%和100%;PWL3和PWL4在两省中的分布频率具有显著差异，这2种基因在黑龙江菌株中频率分别为89.30%和82.79%，而在海南菌株中均为5.49%。通过对无毒基因组合进行分析，结果显示，组...     

菠萝泛菌与水稻白叶枯病菌双重PCR检测方法的建立与应用

近年来水稻发生了一种由菠萝泛菌Pantoea ananatis引起的新型细菌病害，其发生时期与白叶枯病相近，病症与白叶枯病类似。为了实现该病害与白叶枯病的快速检测，本研究基于泛菌属看家基因acnA,通过序列比对，设计了22对特异性引物，分别与已知的白叶枯病菌检测引物XOO80进行配对并筛选，建立了一种双重PCR检测方法，可从菠萝泛菌和白叶枯病菌中分别扩增出910 bp和162 bp的特异性条带，而其他10种非目标细菌均未有扩增条带，25μL体系中可稳定地从至少1 pg/μL的基因组DNA模板中扩增出特异性条带。本研究建立的菠萝泛菌与水稻白叶枯病菌双重PCR检测方法具有良好的特异性和灵敏度，为水稻细菌病害病原鉴定及防治提供了技术支撑。     

茭白叶黑斑病的病原鉴定和防治药剂筛选

In recent years, in addition to brown spot disease, leaf black spot has occurred frequently and seriously affected the yield and quality in the production areas of Zizania latifolia in China. In order to identify the pathogen, diseased samples were collected from Lu'an, Suzhou, Tongxiang, Yuhang, Yuyao, Jinhua, Shengzhou. Finally, 90 fungal strains were obtained by tissue isolation method, in which 25 strains causing black spot disease of Z. latifolia was identified as Nigrospora oryzae by morphological observation, multiple sequence alignment analysis and pathogenicity test. Toxicity test of 12 fungicides commonly used in fields was carried out in laboratory conditions. The results showed that the effect of 250 g·L^-1 prochloraz EC was best, with the EC₅₀ of 0.002 mg·L^-1; followed by 30% Pyraclostrobin SC and 60% Difenoconazole WG, with the EC₅₀ of 0.056 and 0.057 mg·L^-1, respectively. Combined with the inhibitory effect of the 12 fungicides on Ustilago esculenta, 250 g·L^-1 prochloraz EC was the best choice as a control agent. This study provided scientific basis for the identification and control of leaf black spot of Z. latifolia.     

硫藤黄链霉菌St-79对水稻白叶枯病的防效和促生作用

【目的】水稻白叶枯病是水稻的主要细菌性病害之一，严重影响水稻生产。本研究获得一株有效防治水稻白叶枯病的放线菌菌株，探索其对白叶枯病的防效和促进水稻生长的作用，为生防菌的开发利用提供科学依据。【方法】利用梯度稀释涂布法、共培养法和牛津杯法筛选拮抗水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae, Xoo)的放线菌菌株；通过形态特征、生理生化反应、16S rDNA序列和系统发育树分析对其进行分类鉴定；利用共培养法分析目标菌株的抗菌谱；通过96孔板微量稀释法、扫描电子显微镜、微生物粘附碳氢化合物法等探究目标菌株的抑菌作用；通过发酵滤液浸种与菌液喷洒土壤的方法探究其对水稻生长的促进作用；利用盆栽试验探索目标菌株发酵滤液对水稻白叶枯病的防治效果。【结果】从不同生境土壤中分离出140株放线菌菌株，最终筛选得到一株对Xoo具有强拮抗活性的放线菌菌株St-79，其发酵滤液抑菌圈直径为64 mm，并鉴定其为硫藤黄链霉菌(Streptomyces thioluteus)。菌株St-79对水稻细菌性条斑病菌(Xanthomonas oryzae pv. oryzicola)、大豆细菌性斑疹病菌(Xanthomonas axonopodis pv. glycines)、油菜黑腐病菌(Xanthomonas campestris pv. campestris)和番茄细菌性叶斑病菌(Pseudomonas syringae pv. tomato)均有拮抗作用。其乙酸乙酯粗提物具有良好的抑制Xoo生长的效果，粗提物对Xoo的最低抑菌浓度为8 μg/mL，最低杀灭浓度为32 μg/mL；扫描电镜观察结果显示，粗提物对Xoo细胞有很强的损伤作用；粗提物还能改变Xoo细胞内膜通透性，降低Xoo细胞的疏水性。促生试验结果显示，菌株St-79发酵滤液能够促进水稻幼苗的生长。盆栽试验结果显示，菌株St-79发酵滤液对水稻白叶枯病有良好的防治效果，在日本晴、甬优15、甬优1540上的相对防效为65.95%~87.23%，病斑抑制率为69.85%~95.8%，且预防效果优于治疗效果。【结论】获得一株有效防治水稻白叶枯病的放线菌，其对水稻白叶枯病菌有明显的抑制作用，并且可以促进水稻种子的萌发与幼苗的生长。