豇豆轮纹病病菌产毒条件筛选及毒素活性测定

采用种子萌发抑制率和种子胚芽抑制率的检测方法,研究了豇豆轮纹病病原菌（Corynespora cassiicola）在不同培养基、培养时间、培养温度、培养液pH、光照和振荡条件下粗毒素的产生及其活性。试验结果表明：不同的培养条件下病原菌产生毒素活性不同,查彼培养液为最佳培养液,振荡培养可以促进毒素的产生,最适的产毒pH为7~8,最适温度为20~25 ℃,最佳培养时间为15 d,光照条件下病原菌粗毒素的活性最大。豇豆轮纹病粗毒素对于不同寄主的活性测定结果表明：豇豆轮纹病菌毒素接种的10种供试植物中,大豆、菜豆致病反应明显,相对的病斑较大,而对黄瓜无致病力,不产生病斑。     

茎枯菌(Corynespora cassiicola)侵染红麻的发病因素

从红麻茎枯病标本中分离出茎枯菌(Corynespora cassiicola),镜检其形态特征,红麻接种茎枯菌后对发病因子进行试验研究.结果表明:发病适温28℃,饱和湿度有利于发病;孢子悬液最适含量为5.5×103个.mL-1以上,其含量愈高发病情况愈严重;病菌主要侵染麻秆,其次叶片,典型病斑梭形,表生黑色绒毛状霉层,分生孢子多为单生,倒棍棒状,3-26个假隔膜;菌丝和孢子皆能直接或从伤口侵入麻秆发病;幼苗10 d内为感病期;嫩叶易感病;不同品种接种后在麻秆上产生的病斑长度和病情指数有显著差异.     

Distribution and molecular characterization of Corynespora cassiicola isolates resistant to boscalid

A total of 618 isolates of corynespora leaf spot fungus (Corynespora cassiicola) collected from 24 commercial cucumber greenhouses in 12 cities in Ibaraki Prefecture, Japan, were tested for their sensitivity to boscalid. Boscalid‐resistant isolates were detected in 17 out of 19 greenhouses with a history of use of this fungicide and detection frequencies of the resistant isolates exceeded 47% in nine greenhouses. Frequencies of very highly resistant (VHR) isolates with 50% effective concentration (EC₅₀) values of boscalid exceeding 30 μg mL^?1 were higher than those of moderately resistant (MR) isolates with EC₅₀ ranging from 2·0 to 5·9 μg mL^?1 in 11 greenhouses. Additionally, highly resistant (HR) isolates with EC₅₀ from 8·9 to 10·7 μg mL^?1 were first detected. Furthermore, molecular characterization of genes encoding succinate dehydrogenase (SDH) subunits (SdhA, SdhB, SdhC and SdhD) was carried out to elucidate the amino acid substitution responsible for the resistance to boscalid. All 23 VHR isolates had the same mutation from CAC to TAC in the SdhB gene leading to the substitution of histidine with tyrosine at amino acid position 278 (B‐H278Y). At the same position, the substitution to arginine conferred by a mutation to CGC (B‐H278R) was detected in all four HR isolates. Some MR isolates showed a substitution from serine to proline at position 73 in SdhC (C‐S73P), from serine to proline or from glycine to valine at position 89 (D‐S89P) and 109 (D‐G109V), respectively, in SdhD. There was no common mutation in SDH genes of all MR isolates.     

橡胶树多主棒孢病菌强致病菌株的筛选及产毒条件优化

从采白海南、云南和广西的橡胶树棒孢霉落叶病病样中分离获得17株单孢菌株,致病性测定结果表明,来自海南的HC-10菌株致病性最强.HC-10产毒条件及毒素活性测定结果表明,改良Fries 3号培养基、25℃光照12 h培养10 d、转速为160r/min以及培养基初始pH值为4最有利于毒素的产生;温度、紫外线及不同的毒素浓度与毒素的活性存在一定的相关性.     

不同寄主多主棒孢对橡胶树叶片组织防御酶活性的影响

以分离自4种寄主的5株多主棒孢菌株接种橡胶树叶片,均得到成功侵染。并按时间顺序测定了来自不同寄主的多主棒孢侵染橡胶树叶片后,细胞防御系统相关的4种酶活性的变化。结果表明,接种来自不同寄主的多主棒孢后,对橡胶树叶片4种防御酶活性的影响不同。其中分离自橡胶树的HCCGD01和HCCHN42两个菌株侵染后,橡胶树叶片组织4种防御酶活性变化最大,均有明显增强;来自木薯的MaCCGD02侵染橡胶树叶片后,酶活性变化次之;分离自番木瓜的CpCCYN01和黄瓜的PaCCSD04多主棒孢菌株侵染后,除PAL外,β-1,3-葡聚糖酶、POD、PPO活性变化很小。     

Corynespora blight of sweet pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis>) caused by <Emphasis Type="Italic">Corynespora cassiicola</Emphasis> (Berk. &; Curt.) Wei

In 2004, Corynesopra cassiicola was isolated from dark brown spots on leaves and fruits and from black blights on stems of sweet pepper plants in Kochi Prefecture, Japan. The isolated fungus was then used to inoculate sweet pepper plants and subsequently reisolated from the plants with dark brown spots and black blights, showing that C. cassiicola is a new pathogen causing Corynespora blight on sweet pepper plants. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases as accession numbers AB366649 (TS-C11), AB366650 (TS-C21), AB366651 (TI-C32) and AB366652 (TI-C51)     

解淀粉芽胞杆菌YB114对黄瓜棒孢叶斑病的生防效果及发酵条件优化

解淀粉芽胞杆菌YB114为本研究团队筛选出的一株对黄瓜棒孢叶斑病(Corynespora leaf spot)具有较高活性的生防菌株。为加快其产业化进程,本试验研究了该菌株的生物活性及发酵条件。盆栽试验结果表明,100倍发酵稀释液处理对黄瓜棒孢叶斑病的治疗及预防效果分别为85.72%和42.29%,100倍发酵上清稀释液的治疗及预防效果分别达到74.14%和33.25%,菌株发酵液和上清液对黄瓜棒孢叶斑病的治疗效果好于预防效果。YB114发酵液对黄瓜植株有促生效果,叶面喷施后黄瓜茎长、根长、叶面积及地上部生物量增加,叶片中叶绿素、生长素和玉米核苷素含量显著增加。发酵最优培养基为10 g/L果糖、17 g/L水溶性花生饼粉、1 g/L磷酸二氢钾。最佳发酵条件为：装液量40 mL/250 mL三角瓶,接种量6%(体积分数)、pH 7.0,转速180 r/min,温度32℃,发酵时间24 h。优化发酵条件后YB114对棒孢叶斑病的防效提升了22.4%。     

多主棒孢霉分生孢子萌发因素的研究

对影响多主棒孢霉分生孢子萌发的因素进行研究。结果表明,在30℃水膜存在的条件下,多主棒孢霉分生孢子培养2 h即可萌发,6 h后分生孢子萌发率达到较高水平;分生孢子萌发形式多样,可从一端、两端、一端一侧、两端一侧长出条芽管。不同黄瓜品种叶表露珠及叶片研磨液对分生孢子萌发率、芽管数量、菌丝长短有显著影响。抗病黄瓜品种叶片研磨液对该菌分生孢子萌发起抑制作用。     

黄瓜褐斑病菌的产毒培养条件及其毒素的致病范围

对黄瓜褐斑病菌产毒条件和毒素的致病范围进行了研究,结果表明,不同的pH值、温度、光照条件、培养天数所制备的毒素毒力差异显著,病菌的最佳产毒条件是室温25℃,光照12 h、pH值为6、振荡培养15 d;不同植物对病菌毒素的敏感性不同。     

黄瓜棒孢叶斑病(Corynespora cassiicola)的研究概况

黄瓜棒孢叶斑病(Corynespora cassiicola)是近年来国内流行的一种新病害,对黄瓜生产造成的损失日益严重。本文综述了黄瓜棒孢叶斑病的命名、分类、发病规律、抗病鉴定技术、抗病资源和防治方法。并针对研究中存在的问题,对今后的研究方向进行了展望。