Age-related resistance to Pseudomonas syringae pv. tomato is associated with the transition to flowering in Arabidopsis and is effective against Peronospora parasitica

As plants mature it has been observed that some become more resistant to normally virulent pathogens. The ability to manifest the Age-Related Resistance (ARR) response in Arabidopsis to Pseudomonas syringae pathovars tomato (Pst) coincided with the transition to flowering in plants both delayed and accelerated in the transition to flowering. ARR was also associated with a change in PR-1 gene expression, such that young plants expressed PR-1 abundantly at 3 days post inoculation (dpi) while mature plants expressed much less. The Arabidopsis ARR response requires SA accumulation via isochorismate synthase (ICS1) [24]. ICS1 was expressed one dpi with virulent and avirulent Pst in both young and mature plants. The ARR response was also effective versus avirulent Pst providing an additional 4-fold limitation in bacterial growth. Arabidopsis ARR was found to be ineffective against two necrotrophs, Erwinia carotovora subspecies carotovora (bacterium) and Botrytis cinerea (fungus) and one obligate biotroph, Erysiphe cichoracearum (fungus). However, mature wild type, SA-deficient sid2 and NahG plants supported little growth of the obligate biotrophic oomycete, Peronospora parasitica. Therefore ARR to P. parasitica appears to be SA-independent, however the level of ARR resistance was somewhat reduced in these mutants in some experiments. Thus, there may be numerous defence pathways that contribute to adult plant resistance in Arabidopsis.     

猕猴桃溃疡病生防芽孢杆菌B2的鉴定及应用

猕猴桃溃疡病是一种毁灭性细菌病害,该病发展迅速,防治难度大,严重制约了猕猴桃产业的发展。为找到一种有效防治该病的方法,针对化学防治易产生抗药性、污染环境、杀伤天敌等特点,从猕猴桃根际土壤中分离共获得25株芽孢杆菌,采用点菌法筛选出4株对猕猴桃溃疡病菌(Pseudomonas syringae pv.actinidiae)具有拮抗效果的菌株(抑菌圈直径达到5 mm以上),其中B2拮抗作用最强。根据菌落(体)形态特征、生理生化鉴定以及16S r DNA序列分析,初步鉴定B2为蜡样芽孢杆菌(Bacillus cereus)。将B2的发酵原液稀释成1×109cfu/m L的发酵液,并在此基础上依次配制50、100、500、1000、2000倍的稀释液,用于盆栽试验。盆栽试验采用喷雾法,30天后的防治效果分别达到了90.45%、86.52%、80.90%、67.98%、47.19%、15.73%,60天后尽管病斑有少量增加,旧病斑有所增大,但与对照相比,病斑增长速度明显减缓。大田试验结果证明,该菌具有较好的生防潜力,喷雾法选择B2发酵液的50倍稀释液,涂抹法选择B2发酵液的100倍稀释液,可有效降低猕猴桃溃疡病的危害。     

Identification of QTLs Associated with Resistance to Pseudomonas syringae pv.Glycinea in Soybean (Glycine max (L.) Merr)

Soybean bacterial spot disease caused by Pseudomonas syringae pv.Glycinea which is a bacterial disease seriously affects soybean yield.Ten soybean germplasms and recombinant inbred lines (RILs) population were used to identify the resistant trait after inoculated with P.sg (P.sgneau001) in this study.High-density genetic mapping was obtained by specific length amplified fragment sequencing (SLAF-seq) of 149 RILs population which was derived from the crossing between Charleston and Dongnong594.The results indicated that 10 germplasm resources had four resistant germplasms included highly resistant cultivar Charleston,four susceptible varieties included Dongnong594 and two moderately resistant cultivars.Five quantitative trait locus (QTLs) were detected in RILs population by the composite interval mapping (CIM) method,and located on Linkage Group (LG) D1b (chromosome two),LG C2 (chromosome six) and LG H (chromosome 12),respectively.LOD scores ranged from 2.68 to 4.95 and the phenotypic variation percentage was from 6% to 11%.Six candidate genes were detected,according to the result of gene annotation information.Four of them had relationship with protein kinase activity,protein phosphorylation and leucine rich repeat (LRR) transmembrane protein,which had high expression after inoculated with P.sg by qRT-PCR.     

猕猴桃细菌性溃疡病研究进展

笔者总结了近年来国内外学者对猕猴桃细菌性溃疡病的研究和发现,详细介绍了猕猴桃细菌性溃疡病的症状、危害和传播途径以及致病菌Pseudomonas syringae pv. actinidiae的特征、分类和起源,分析了其可能的致病机理并总结了猕猴桃的抗病性研究。基于目前对猕猴桃细菌性溃疡病的防治方法和相关研究发现,展望了猕猴桃细菌性溃疡病的研究方向和防治措施,提出采取预防致病菌传入、增强树势和药剂防治相结合的防治措施,为以后的研究和生产实践提供了理论依据。     

猕猴桃细菌性溃疡病研究进展

笔者总结了近年来国内外学者对猕猴桃细菌性溃疡病的研究和发现,详细介绍了猕猴桃细菌性溃疡病的症状、危害和传播途径以及致病菌Pseudomonas syringae pv. actinidiae的特征、分类和起源,分析了其可能的致病机理,并总结了猕猴桃的抗病性研究。基于目前对猕猴桃细菌性溃疡病的防治方法和相关研究发现,展望了猕猴桃细菌性溃疡病的研究方向和防治措施,提出采取预防致病菌传入、增强树势和药剂防治相结合的防治措施,为以后的研究和生产实践提供理论依据。     

陕西关中地区猕猴桃溃疡病菌对CuSO4的抗性评价

为明确陕西省猕猴桃细菌性溃疡病菌（Pseudomonas syringae pv.actinidiae,Psa）对CuSO₄的抗性水平及与copA和copB基因表达量的相关性,使用最小抑菌浓度法（MIC）对分离自陕西省关中地区的84株Psa菌株对于CuSO₄的抗性进行检测。在此基础上,使用实时荧光定量PCR方法,对3株不同抗性水平Psa菌株的基因copA和copB与抗铜性的关系进行了分析。结果表明,供试的84株Psa菌株MIC分布在3.75~6.25 mmol·L^-1范围内;不同地区来源的菌株对CuSO₄的抗性表现出明显的差异,其中分离自周至的Psa菌株的抗铜水平明显高于眉县。实时荧光定量PCR分析结果显示,不同浓度CuSO₄条件诱导下,3株不同抗性水平的菌株抗铜基因copA和copB表达水平与CuSO₄浓度成正相关,且菌株的抗性水平越高,基因copA和copB相对表达水平亦越高。陕西省关中地区的Psa菌株对CuSO₄表现出较高的抗性水平,且不同地区的Psa菌株的抗性表现出明显差异;copA和copB基因参与了Psa菌株对铜离子的适应性反应。     

桔梗叶斑病病原细菌的鉴定

2000-2001年在江苏、浙江、安徽等地发现一种桔梗病害，并从其病叶上分离得到了26个菌株。菌株接种于桔梗叶片后，发病症状与自然发病症状完全一致，并从回接病株上重新分离得到此病原菌。各菌株间致病力无明显的差异。经革兰氏染色反应、菌体形态、培养性状、生理生化反应、（G C）%等鉴定，确定该病原菌为丁香假单胞杆菌的一个新的致病变种。该病菌能引起桔梗细菌性叶斑病（又称斑点病）。     

烟草野火病菌(Pseudomonas syringae pv. tabaci)对烟草细胞内5种防御酶系统的影响

定期测定了感病品种红花大金元接种烟草野火病菌后叶片内5种酶活性的动态变化，研究结果表明：烟草接种病菌后，SOD活性先上升，后在8d下降，低于对照；POD活性接种后在1d略低于对照，后上升较快，10d达到高峰，此后一直高于对照；PPO活性在接种后1d低于对照15.8%，但此后上升，16d达到高峰，18d下降低于对照；CAT活性变化与POD相似，接种1d低于对照，但此后一直高于对照，并于6d达到高峰，10d虽有所下降，但接着升高；PAL活性与CAT、POD变化相似，接种后1d活性低于对照28.3%，其后上升，10d达到高峰，是对照的2.11倍，并维持较高的水平。     

云南省烟草野火病菌毒素的致病性评价*

 主要通过对烟草野火病菌菌株（Pseudomonas syringae pv. tabaci）致病力与其粗毒素毒力的相关性的研究，评价了烟草野火病菌毒素在致病过程中的作用。结果表明：①野火菌毒素毒力与其菌株的致病力呈极显著相关性，相关系数r达0.928；②高感和中感品种K326,云85对病原菌的感病性与对菌毒素的敏感性在P<0.05的水平上有相关关系；③从病斑处可以分离到该毒素，再接种能重现野火病症状；④抑菌物质对病原菌和病菌毒素的抑制作用相一致。     

不同烟草品种对云南烟草野火病菌的抗性鉴定*

 采用采自云南省不同地点、不同生理小种的24株烟草野火病菌对24个不同烟草品种及两个野生种黄花烟和长花烟进行抗病性鉴定分析。结果表明,不同抗性品种对不同生理小种的抗性反应差异显著,根据接种后不同烟草品种的形成的病斑直径,将其划分为4个等级：高抗、中抗、中感、高感。辽烟15,G28对于烟草野火病菌0,1号生理小种均表现为高感,而云南省大面积栽培的K326、红花大金元、云烟87等对于两个生理小种均表现为中感,而两个野生种黄花烟和长花烟均表现为高抗,可以作为烟草野火病抗性育种优先利用的种质资源。