向日葵黄萎病菌不同培养型产毒能力和致病力分化

为了明确向日葵黄萎病菌间毒素产生能力以及致病力存在着分化现象,本文选取5种不同培养型的向日葵黄萎病菌对其菌落生长速度、粗毒素含量、毒素致萎活性及致病力进行测定。结果表明,不同培养型的黄萎病菌分生孢子的形态没有显著差异,但是菌株生长速度、粗毒素产生量及其致萎能力存在一定的差异。粗毒素产生能力高的菌株,其致萎能力也强,如菌株V33(产生大量微菌核)、V21(不产生微菌核)、V27(产生一定量的微菌核及气生菌丝)的粗毒素分泌量分别为0.36、0.34、0.23mg/mL,其72h的致萎指数为58.33、52.08、37.50。采用纸钵撕底蘸根法对供试菌株的致病力进行测定,结果表明,不同培养型黄萎病菌的致病力存在一定的分化现象。其中致病力最强的菌株是V33,其病情指数为53.97;其次是菌株V21和V39(产生大量微菌核)其病情指数分别为45.91和43.35;菌株V27的致病力最弱,其病情指数为37.44。相关性分析的结果表明,菌株致病力的强弱与其分泌的粗毒素含量呈显著的正相关关系（R2=0.8169,P<0.05）,但与其菌落生长速度以及微菌核的数量没有相关性。向日葵黄萎病菌毒素的分泌量是决定其致病力分化的关键因子。     

我国花生青枯病研究进展

花生青枯病是一种世界性病害,在全球20多个国家均有发生,严重影响花生产量及品质。本文查阅相关文献,对我国有关花生青枯病的研究报道进行总结,描述了花生青枯病的发生与分布、病原菌种及其危害症状以及传播流行规律等,对花生青枯病的防治方法及抗性育种研究进展进行综述,并对花生青枯病的研究方向进行展望,以期为我国花生青枯病的综合防治提供参考。     

Variability in the response toPseudomonas solanacearum of transgenic lines of potato carrying a cecropin gene analogue

Summary Transgenic potato plants of cv. Désirée carrying an antibacterial gene, coding for a cecropin lytic peptide analogue, were inoculated with a virulent strain ofPseudomonas solanacearum under controlled conditions. The disease index scored during three repeated infection trials indicated an increased variability in plant response among the transgenic lines which gave either a more susceptible or a more resistant response to the pathogen when compared with untransformed Désirée. Immunity toP. solanacearum was not observed, but it was possible to select a group of transgenic lines that showed resistance levels and disease development curves comparable to the field resistant cv. Cruza 148.     

Fusarium commune associated with wilt and root rot disease in rice

Wilt and root rot disease in plants has been caused mainly by Fusarium species. Previous studies reported that members of the Fusarium oxysporum species complex (FOSC) were usually associated with this disease, but there has been no report of it being caused in rice by specific Fusarium species. However, in this study, Fusarium commune was identified and characterized as a causal agent of wilt and root rot disease of rice. Four Fusarium isolates (BD005R, BD014R, BD019R, and BD020R) were obtained from different parts (root, stem, and seeds) of diseased rice plants. In morphological studies, these isolates produced key characteristics of F. commune, such as long and slender monophialides, polyphialides, and abundant chlamydospores. In molecular studies, the isolates were identified as F. commune based on sequences of the translation elongation factor 1-α (TEF1) gene that had 99.7%–100% sequence identity with the reference strain F. commune NRRL 28058. The phylogenetic tree showed that all four isolates belonged to the F. commune clade. A mating type test determined that three isolates carried MAT1-2. Their teleomorph stage was still unknown. Pathogenicity assays showed that all the isolates produced wilt and root rot symptoms and the isolate BD019R was observed as the most virulent among the isolates. To our knowledge, this is the first report of F. commune causing wilt and root rot disease on rice.     

生防菌株LB-1培养液对黄瓜的抑病促生作用

 LB-1为新筛选的生防近缘毛壳(Chaetomium subaffine)菌株。为明确LB-1培养液的抑病促生效果,本研究以黄瓜为供试植物,分别采用灌根和叶面喷施的方式,测定了LB-1培养液对黄瓜枯萎病和黄瓜白粉病的抑制效果;通过种子萌发、盆栽苗和生化检测试验,分析了LB-1培养液对黄瓜的促生作用。结果发现,LB-1培养液对黄瓜枯萎病抑制作用效果甚微,但对黄瓜白粉病生防效果明显,黄瓜叶片接菌24 h后叶面喷施LB-1培养液对白粉病的防效高达48.86%。LB-1培养液浸润催芽处理24 h的黄瓜种子萌发率和根长均显著高于对照(P=0.05),且LB-1培养液浸种、灌根、叶面喷施处理均能促进黄瓜幼苗的生长发育。LB-1没有产嗜铁素、产氢氰酸、固氮和溶磷能力,但能够产生吲哚乙酸(Indoleacetic acid,IAA)。表明生防菌株LB-1培养液能有效抑制黄瓜白粉病的发生,促进黄瓜种子萌发和植株生长,而且其促生作用可能通过产生IAA来实现。     

滴灌条件下枯草芽胞杆菌S37和S44对棉花黄萎病的防治效果

采用拌种和随水滴施2次的方法测定了2株芽胞杆菌对棉花黄萎病的防治效果。结果表明,在滴灌条件下2株枯草芽胞杆菌对棉花黄萎病均表现出较好的防治作用,在小区试验中,S37和S44对棉花黄萎病的防治效果分别为29.86%和42.81%,产量分别增加了25.22%和34.73%。在田间试验中,S37在143团和147团的防病效果分别为51.3%和55.1%,增产效果分别达到7.43%和17.62%,S44在143团和147团的防病效果分别为35.2%和39.3%,增产效果分别达到5.56%和15.51%。     

类芽胞杆菌W51菌剂制备及对番茄青枯病的防效研究

青枯病是由青枯劳尔氏菌Ralstonia solanacearum引起的一种土传病害。本研究将制备得到的伊利石吸附W51菌剂作用于防治番茄青枯病的温室试验。结果表明,伊利石吸附W51菌剂中的伊利石最佳剂量为4%,最佳吸附时间为30 min,在该条件下伊利石对菌体的吸附率达到90.78%;温室试验中,伊利石吸附W51菌剂处理组在第14 d仍然表现出较好的防效62.29%,远高于类芽胞杆菌Paenibacillus sp.W51菌悬液处理组的42.91%。本研究表明,伊利石吸附W51菌剂相对于单一的类芽胞杆菌Paenibacillus sp.W51对番茄青枯病有较高的防治效果。     

贝莱斯芽胞杆菌SDTB038与化学药剂协同防治草莓枯萎病的研究

草莓枯萎病是设施草莓连作种植中的重大病害,本试验通过对前期筛选到的生防菌株进行形态学观察、生理生化指标和分子生物学检测,将筛选的菌株SDTB038鉴定为贝莱斯芽胞杆菌Bacillus velezensis。采用菌丝生长速率法测定了8种化学杀菌剂对草莓枯萎病菌的毒力,其中多菌灵、苯醚甲环唑和肟菌酯室内毒力较高。菌株SDTB038与化学杀菌剂协同防治的盆栽试验表明,药后21 d,单施10⁸ cfu/mL SDTB038发酵液对草莓枯萎病的防治效果为50.66%,对该病害具有明显的防控作用。10⁸ cfu/mL SDTB038发酵液分别与29 mg/L肟菌酯和20 mg/L苯醚甲环唑混用,对草莓枯萎病的防治效果分别达62.56%和74.01%,两组混用组合的协同作用显著。试验结果表明,10⁸ cfu/mL SDTB038发酵液能够减少化学药剂的用量,提高防治效果,推广应用价值大。     

木麻黄青枯病风险分析

木麻黄青枯病是危害木麻黄生长的植物土传病害,严重者可造成木麻黄的大面积死亡。通过定性因素和定量指标体系对木麻黄青枯病进行风险分析,评估结果显示,其风险综合评价值为1．54,属于中度危险性林业有害生物。     

不同砧木嫁接对番茄生长及抗青枯病的影响研究

以亲和番茄、亲家番茄、本地野生刺茄作砧木,以达尔文番茄、绿樱1号樱桃番茄为接穗,探讨不同砧木嫁接对番茄生长发育及抗青枯病的影响.结果表明,嫁接可显著提高番茄抗青枯病的能力;在生长发育方面,以本地野生刺茄做砧木与两个接穗的亲和力明显不如亲和、亲家两个番茄砧木,随着生长,本地野生刺茄与两个接穗的不亲和现象越明显,表现在嫁接部位砧木的茎粗显著小于接穗,植株矮化、生理性早衰,果实变小;在产量方面,用亲和、亲家番茄做砧木嫁接,能延长番茄采收期,增加番茄的结果数,提高番茄的单果重,使总产量增加15％以上.