4种种衣剂对大豆根腐病的防效比较

[目的]研究4种种衣剂防治大豆根腐病的综合效应。[方法]以大豆主栽品种阿豆1号作为试材,将大豆种子采用4种种衣剂处理后播种在根腐病严重的病土中,测定其出苗率、株高、病株率、死亡率、病情指数等指标。[结果]在根腐病严重的土壤条件下,4种种衣剂处理中,除处理Ⅰ和Ⅳ的出苗率显著低于对照以外,处理Ⅱ和Ⅲ均保持与对照相同的水平;虽然种衣剂处理后,大豆须根数量有一定程度的减少,但其株高有所提高,病株率、死亡率和病情指数有不同程度的下降。[结论]4种种衣剂对大豆根腐病的防病效果有差异,效果大小顺序依次为36.8%阿维菌素.多菌灵.福美双(ADF)悬浮种衣剂(Ⅱ)、40%卫福悬浮种衣剂(Ⅲ)、35%kdf悬浮种衣剂(Ⅰ)、18%福克悬浮种衣剂(Ⅳ)。     

Production of hydrogen peroxide and expression of ROS‐generating genes in peach flower petals in response to host and non‐host fungal pathogens

Reactive oxygen species (ROS) play dual roles in plant–microbe interactions in that they can either stimulate host resistance or enhance pathogen virulence. Innate resistance in peach (Prunus persica) to the brown rot fungal pathogen Monilinia fructicola is very limited, and knowledge of the mechanism of virulence is rudimentary. In this study, production of hydrogen peroxide, a major component of ROS, was determined in peach flower petals in response to M. fructicola (a host pathogen) and Penicillium digitatum (a non‐host pathogen). Monilinia fructicola was able to infect flower petals while P. digitatum was not. During the host‐specific interaction, M. fructicola induced hydrogen peroxide accumulation in flower petals. Application of exogenous antioxidants significantly reduced hydrogen peroxide accumulation as well as the incidence of brown rot disease. Application of M. fructicola spores to the surface of intact flower petals induced gene expression and increased enzyme activity of NADPH oxidase and cell wall peroxidase in host tissues, resulting in the production of hydrogen peroxide. Petals inoculated with M. fructicola exhibited high levels of protein carbonylation and lipid peroxidation. No significant response in gene expression, enzyme activity or hydrogen peroxide levels was observed in peach flower petals treated with P. digitatum. These results suggest that M. fructicola, as with other necrotrophic fungi, uses the strong oxidative response as part of a virulence mechanism.     

Medicago truncatula as a model host for studying legume infecting Rhizoctonia solani and identification of a locus affecting resistance to root canker

The broad‐host‐range necrotizing fungal pathogen Rhizoctonia solani is responsible for economically significant diseases to crops as diverse as wheat, maize, barley, canola, sugar beet, potato, soyabean, bean, lupin and alfalfa. Germplasm screens in many of the crop hosts have not identified strong genetic resistance which, together with the lack of effective control, mean the pathogen remains a substantial problem for agriculture in many parts of the world. Following the establishment of a robust inoculation assay, a germplasm collection of the model legume Medicago truncatula was screened with various legume‐infecting isolates of R. solani. While some significant differences in susceptibility/resistance were detected between some lines, in the majority of cases M. truncatula was susceptible to R. solani. Comparison of a legume‐ and cereal‐infecting AG8 isolate with a legume‐specific AG11 isolate revealed no difference in pathogenicity between the two isolates when infecting M. truncatula. The most significant differences in susceptibility occurred with an AG6 isolate, which caused root canker. This included significant differences between the moderate resistance of the M. truncatula reference genotype A17 and the high susceptibility of line A20. The analysis of a recombinant inbred line population derived from A17 and A20 revealed a single locus contributing to the resistance in A17. Interestingly, the locus only affected the development of post‐emergent (late) symptoms, such as necrosis of cotyledons at 11 days after inoculation and root‐ and above‐ground‐weights, but not pre‐emergent seedling damping off. These findings pave the way for further studies to dissect the genetic and molecular mechanisms of resistance.     

迷迭香根腐病病原菌的鉴定

 迷迭香（Rosmarinus officinalis L.）又名油安草,艾菊,属于唇形科迷迭香属植物,为多年生常绿亚灌木,是地中海一带的重要景观植物。因其香味浓郁,被应用于香水、香皂、空气清新剂和食品添加剂生产中;该植物在医药方面还具有催经活血、利胆降压和抗癌等药理作用^［1］。近年来,广西百色市大量种植迷迭香,但在种植区普遍发生一种根茎部病害,造成植株根茎部腐烂,最终全株干枯死亡。每年5~9月份高温多雨季节,一般田块发病率为5%~10%,严重时发病率达40%,给迷迭香的生产造成一定的经济损失。国外曾报道Armillaria,Phytophthora和Rhizoctonia均可引起迷迭香根部病害^［2］,但目前国内对迷迭香的研究主要集中在其化学成分和药理作用上,未见有关病害的报道。本文对迷迭香根腐病的病原菌进行鉴定,为研究该病害的发病流行规律及制定病害防治措施奠定了基础。     

河北和内蒙古马铃薯干腐病菌种类鉴定

为明确河北和内蒙古马铃薯干腐病菌种类和优势种群,从两省采集300块具干腐病症状的样品,通过分离培养、形态鉴定、TEF-1α序列分析及致病性测定等,对马铃薯干腐病菌种类进行了系统研究.结果表明,两省马铃薯干腐病共存在4种病原菌,即接骨木镰刀菌Fusarium sambucinum、锐顶镰刀菌F.acuminatum、尖孢镰刀菌F.oxysporum和芬芳镰刀菌F.redolens,分别为149、80、3、3株.其中,河北省的优势种群为接骨木镰刀菌和锐顶镰刀菌,其发生频率分别为50％和48.68％;内蒙古的优势种群为接骨木镰刀菌,发生频率为87.95％.     

Charcoal rot in common bean with special reference to Kenya

Abstract

Charcoal rot caused by Macrophomina phaseolina (Deuteromycetes: Coelomycetes) is found throughout the tropics and subtropics and has a wide host range. Together with most of the legume crops, the common bean (Phaseolus vulgaris) Is a good host for the fungus which causes a range of symptoms, depending on environmental conditions and age of the plant. In addition to charcoal rot, which is a stem or stalk rot disease, the pathogen also causes damping‐off and seedling blight in beans. Charcoal rot in the mature plant is associated with senescence which is accelerated by water stress. The disease is most damaging in areas of unreliable rainfall and high temperature. In Kenya, beans are usually grown in mixed stands with maize, sorghum or millet. Population pressure has led to the cultivation of beans on land prone to drought. M. phaseolina is one of the most important pathogens affecting all the main crops of the farming systems in the semi‐arid areas of eastern Kenya and resistance to charcoal rot is a priority if beans are to be increasingly grown in these areas. The paper reviews the literature on charcoal rot of beans and on other crops where similar work has not been reported specifically for beans.     

三株拮抗细菌的鉴定及抑菌作用研究

为了充分发掘和利用有益微生物资源,本文以草莓根腐尖孢镰刀菌Fusariumoxysporum为靶标菌,从草莓根际土壤中分离筛选得到3株拮抗细菌,通过培养性状与形态特征、生理生化特征以及16SrDNA同源序列比对分析进行了鉴定,菌株1-9和9—4为多粘类芽孢杆菌Paenibacilluspolymyxa、菌株12—4为枯草芽孢杆菌Bacillussubtilis。这3株细菌对草莓根腐尖孢镰刀菌的抑菌作用进行了初步的研究,结果表明,3株拮抗细菌对草莓根腐尖孢镰刀菌的生长有很好的抑制作用,镜下观察对菌丝有致畸作用,其培养滤液还能够抑制草莓根腐病尖孢镰刀菌分生孢子的产生与萌发。     

超表达亚硫酸氧化酶基因对促进番茄果实亚硫酸盐氧化的研究

本研究以亚硫酸氧化酶基因（SO）超表达系（OE）、干扰系（Ri）及野生型（WT）的绿熟番茄果实为材料,经SO2熏蒸后,12℃低温贮藏,研究亚硫酸氧化酶基因的超表达,对番茄贮藏期间相对电导率、亚硫酸盐含量、番茄红素含量及成熟度的变化。结果表明,经SO2熏蒸后,Ri果实较WT果实表现为相对电导率增加,亚硫酸盐残留较多,番茄...     

石榴干腐病生物生态学及发生流行规律和治理研究

云南蒙自石榴干腐病（Ｚｙｔｈｉａ ｖｅｒｓｏｎｉａｎａ Ｓａｃｃ）以菌丝体为分生孢子在僵果、干腐果及其他感病部位越冬。翌年轻风雨、昆虫和人为活动在果园广为传播。石榴花、幼果、果实期均可感病发病,萼筒花丝最易感病。果实发病率达２０％～３０％,重者达４０％～５０％。采取综合治理措施,其中重要的是在首次连续降雨前刮去干花丝、套袋和树冠多次喷清水,提前水解、淡化干花丝、伤口渗出液的微酸性度,可控制该病的发     

三种防腐剂对马铃薯薯块干腐病菌的毒力及抑制作用

马铃薯干腐病是目前马铃薯贮藏期间发生较严重的一种病害,已成为影响马铃薯贮藏保鲜的瓶颈问题之一。为筛选出施用简便、安全高效且能取代液体类毒性强的防腐剂,试验对二氧化氯、仲丁胺和过氧乙酸三种熏蒸型防腐剂进行了室内毒力测定和抑制效果评价。结果表明：该三种防腐剂对马铃薯干腐病具有不同的抑制活性,其中仲丁胺对马铃薯干腐病的抑菌效果最佳,其毒力回归式为y=3.608 7+7.500 8x,EC50为0.202 8 μg/mL。通过3种防腐剂的体内效果试验,结果表明：在低温条件下,3种防腐剂处理均不同程度地降低了马铃薯块茎的发病率,其中以仲丁胺控制效果最佳,95 μg/kg 浓度处理可明显降低接种马铃薯薯块的发病率和病斑扩展速度。因此可以推断仲丁胺是防治马铃薯干腐病的理想药剂之一。