大豆炭疽病菌(Colletotrichum truncatum)的营养生理研究

大豆炭疽病(Colletotrichum truncatum)是严重危害大豆的病害之一,我国各大豆产区均有发生。该病苗期可引起大豆死苗,成株期可危害茎秆、豆荚,导致大豆产量下降、品质变劣[1-2]。近年来,该病在安徽省大豆,特别是菜用大豆(毛豆)上的危害日趋严重,一般病荚率为10%~20%,重病田病荚率可达50%以上。关于大豆炭疽病的发生和防治以及品种对病原菌的抗性已有少量研究[1-3],但有关大豆炭疽菌的营养生理的研究迄今未见报道。为此,作者在对安徽省大豆炭疽病病原菌分离鉴定的基础上,对不同碳源和氮源营养对大豆炭疽病菌菌丝生长的影响进行了研究,旨在为…     

普通菜豆基因组学及抗炭疽病遗传研究进展

普通菜豆是重要的食用豆类之一,在世界各大洲普遍种植。近年来,普通菜豆在遗传图谱构建、新标记开发与利用、抗性基因定位以及比较基因组学等方面取得了很大进展。遗传连锁图谱的构建是基因定位与克隆的基础,是遗传研究中的重要内容;利用分子连锁图谱鉴定、标记和定位抗病基因将在种质改良和分子标记辅助育种方面发挥重要作用。豆科植物比较基因组学的研究成果为菜豆遗传连锁图谱的发展提供了新的思路。本文从普通菜豆遗传连锁图谱的获得、普通菜豆与大豆同线性比较以及抗炭疽病基因定位等方面进行了综述,以期为普通菜豆遗传改良和抗病育种提供参考。 关键词：普通菜豆;遗传连锁图;同线性比较;抗菜豆炭疽病     

芒果炭疽菌研究进展

芒果炭疽病是芒果生长期和采后贮藏期的主要病害之一,严重影响芒果的产量和品质。本文从芒果炭疽病的症状、病原菌分类鉴定、生物学特性、侵染特性及致病机理等方面进行综述;针对芒果炭疽病症状复杂、我国芒果炭疽病病原菌未获详细而系统的研究,指出全面了解我国芒果炭疽病的病原菌种类及优势种群,明确我国芒果炭疽菌的致病力强弱,有助于研究该病的发生流行规律,为抗病材料的选育和抗病品种在田间的合理布局提供参考。提出对我国芒果炭疽菌的抗药性进行系统监测分析,可防止或减缓芒果炭疽菌对杀菌剂抗药性的产生,从而有效减少化学农药的用量,为研究芒果炭疽病绿色防控新策略、新方法和新药剂奠定基础。     

普通菜豆抗炭疽病基因鉴定与分子标记

菜豆炭疽病是世界菜豆生产中的主要病害之一,使幕豆产量和品质受到严重影响,对抗炭疽病基因的研究可以为培育抗炭疽病品种奠定基础。幕豆炭疽病病菌生理分化比较复杂,由于菜豆品种的抗病性和地域不同,菜豆炭疽菌的致病性分化不同。10个已知抗炭疽病基因中,9个基因（Co-1、Co-2、Co-3／Co-9、Co-4^2、Co-5、Co-6、Co-7、Co-10）已被确认为独立显性基因,其中Co-3／Co-9是等位基因;Co-1、Co-4和Co-9存在等位基因,co-8为隐性基因。除Co-5、Co-7和co-8三个基因还没有被定位外,其他基因被定位在不同的连锁群上。     

不同油茶无性系炭疽病抗性及主要生理指标分析

为选育对炭疽病高抗的油茶(Camellia oleifera)良种,以5个闽西当地的油茶无性系为材料,采用病情指数法进行调查,评价其炭疽病抗性,并测定各无性系叶片的过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及可溶性蛋白含量等指标,分析油茶炭疽病抗性与其主要生理指标的相关性。结果表明,参试的5个油茶无性系中,高抗无性系1个(新罗2号)、中抗无性系3个(河田2号、红山1号、漳平2号)、低感无性系1个(武平2号);不同无性系之间的POD、SOD、CAT活性及可溶性蛋白含量差异均达极显著水平(P<0.01)。相关性分析显示,POD活性、SOD活性、可溶性蛋白含量与油茶炭疽病的感病指数成负相关,CAT活性与感病指数的相关性未达显著水平。综上所述,不同油茶无性系对炭疽病的抗性各不相同,且其主要生理指标与抗性有一定的相关性,其中新罗2号无性系对炭疽病抗性强,主要生理指标也相对较高。该结果为油茶抗炭疽病良种选育及抗病机理研究提供依据。     

13个菜心品种对菜心炭疽病的抗性鉴定

为了解广东省推广种植的菜心Brassica parachinensis品种对菜心炭疽病的抗性水平,对广东省13个具代表性菜心品种进行菜心炭疽病的抗性鉴定。结果显示,供试13个菜心品种对菜心炭疽病的平均病情指数为44.61~74.19,其中80天油青菜心的平均病情指数最低,粗苔49油青甜菜心的平均病情指数最高。80天油青菜心等6个品种对菜心炭疽病表现为中抗水平,粗苔49油青甜菜心等7个品种对菜心炭疽病表现为感病水平。目前在广东省生产种植的菜心以菜心炭疽病感病和中抗品种为主,缺乏菜心炭疽病抗性或高抗品种。     

水貂炭疽的防治

水貂对炭疽病是一种较易感染的动物,炭疽病又是养貂业上的重大危害之一。至今国内未见报道,为了引起各貂场的重视,防治该病的蔓延,现将我场对水貂炭疽病的防治情况简介如下。     

炭疽病:微生物学的一个老问题带来了新烦恼

炭疽病是由炭疽芽孢杆菌的芽孢通过皮肤、胃肠道及肺部侵入人体而造成的。芽孢在体内被巨噬细胞吞噬后萌发并繁殖。带有荚膜的炭疽芽孢杆菌进入血液并释放3种外毒素。外毒素侵入宿主细胞造成患者代谢紊乱而休克致死。根据国外有关炭疽病的最新报道,对炭疽芽孢杆菌的微生物学及炭疽病的发病机理进行了综述。     

银杏外种皮的利用价值

长期以来,银杏采收后,取核弃皮,不仅污染了环境,而且造成了银杏资源的极大浪费。经试验研究,100倍的银杏外种皮酒精提取液对柑桔炭疽病、梨干腐病、枇杷灰斑病、桃炭疽病、苹果炭疽病、梨轮纹病、苹果轮纹病、柑桔树脂病、苹果腐烂病、桃果腐病、葡萄果腐病等病菌具明显的抑制效应,其中对苹果炭疸病、轮纹病;柑桔炭疽病、树脂病;桃果腐病等病原菌的抑制效果达98％以上。大田条件下,50倍的银杏外种皮酒精提取液对苹果炭疽病的防治效果可达80%。用20倍的银杏外种皮酒精提取液对丝棉木金星尺蠖、蛛砂叶螨、桃赤蚜、菜青虫、小菜蛾、28星瓢虫、莲缢管蚜、梨肉蝽、棉铃虫、粘虫和二化螟     

杉木第3代种子园亲本抗炭疽病能力初探

针对广东省杉木第3代种子园建设早期一处小型园区(2 hm²)自然发生的炭疽病害跟踪监测其流行情况。建园后前两年(2016～2017年)均有炭疽病害发生，但对种子园影响不大；建园后2.5年时(2018年)，种子园炭疽病发病事件增多，42.5%嫁接株出现炭疽病症，炭疽病对种子园母株健康影响较大。于发病率较高龄期(2.5年生)调查不同亲本嫁接无性系的感病情况，发现不同亲本(n=56)抗炭疽病能力差异较大(感病率9.1%～81.8%)。根据感病率，初步确定其中5个亲本(cx731、cx841、cx859、cx872、cx876)具有较强的抗炭疽病能力，这些亲本是开展杉木抗炭疽病育种研究的重要候选材料。     

Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis

Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.     

The Integrated Aerobiology Modeling System applied to the spread of soybean rust into the Ohio River valley during September 2006

Soybean rust (Phakopsora pachyrhizi) has recently invaded North America and has the potential to be the most destructive foliar disease of soybean. As part of the response to this threat, the Integrated Aerobiology Modeling System (IAMS) was constructed to forecast the aerial movement of this pathogen from subtropical to middle latitude portions of the continent. IAMS simulations have been conducted daily for the past two growing seasons and integrated with information from a nationwide observation network into a decision support system for soybean farmers. After the 2005 season, the United States Department of Agriculture reported that many millions of United States (U.S.) soybean hectares that would have been treated for soybean rust in 2005 were not due to this decision support system. In 2006, soybean rust appeared for the first time in the major U.S. soybean production region over 1000 km from known areas of inoculum production. IAMS predictions of the geographical extent and timing of disease symptom expression were well matched with subsequent observations of the disease in the field.     

青霉TS67菌株对大豆根腐病和玉米小斑病的防治效果评价

采用盆栽试验的方法,通过病情指数和防治效率等指标研究青霉TS67菌株的发酵液、发酵上清液和菌体对大豆根腐病及玉米小斑病的影响,实验结果的SPSS统计分析表明,青霉TS67的所有处理均能显著(P<0.01)抑制大豆根腐病及玉米小斑病的发生,其中采用TS67菌株与大豆尖孢镰刀菌(Fusarium oxysporum)的混合物进行拌种,对大豆根腐病的防治效果最好,防治效率迭63.98%;在玉米小斑病发病前喷洒TS67菌株的发酵液,对玉米小斑病的防治效果最好,防治效率达到53.34%.此外实验结果还表明用青霉TS67进行大豆拌种能有效促进大豆幼苗生长.     

野生大豆资源对大豆疫病抗病性和耐病性鉴定

大豆疫病是大豆重要病害之一,在世界范围内导致严重经济损失。防治大豆疫病最有效方法是利用抗病或耐病品种。筛选抗性资源是发掘抗性基因和抗病育种的基础。本研究鉴定了野生大豆资源对大豆疫病的抗病性和耐病性,以期发掘优异抗源。苗期用子叶贴菌块方法鉴定104份野生大豆资源对两个不同毒力的大豆疫霉分离物PSJS2(毒力型:1a,1b,1c,1d,1k,2,3a,3b,3c,4,5,6,7,8)和PS41-1(毒力型:1a,1d,2,3b,3c,4,5,6,7,8)抗性,结果表明33份资源抗PS41-1,35份资源抗PSJS2,其中18份抗两个分离物。在抗病性鉴定基础性上,用菌层接种方法对选择的82份资源进行耐病性鉴定,发现7份高耐病性资源。这些结果表明,野生大豆中可能含有新的大豆疫病抗病和(或)耐病资源,这些抗病或耐病资源可以用于未来大豆抗病育种,以丰富大豆对大豆疫病的抗性遗传基础。     

Effect of dsRNA-containing and dsRNA-free hypovirulent isolates of Fusarium oxysporum on severity of Fusarium seedling disease of soybean in naturally infested soil

In the sandy soils of eastern Virginia, soybean seedlings are colonized by hypovirulent and virulent isolates of Fusarium oxysporum and F. solani. Our objectives were to determine if prior inoculation of soybean seeds with hypovirulent F. oxysporum isolates reduced severity of seedling disease in naturally infested soil, and to determine if there was an association between the presence of dsRNA mycovirus and hypovirulence in isolates of F. oxysporum and F. solani from soybean plants. The presence of dsRNA was not associated with hypovirulence in F. oxysporum since some hypovirulent isolates contained dsRNA while other hypovirulent isolates did not. Furthermore, of six dsRNA-containing F. oxysporum isolates, three were hypovirulent and three were virulent. Four segments of dsRNA, with sizes of 4.0, 3.1, 2.7 and 2.2 kb were detected in extracts of all six F. oxysporum isolates. No hypovirulent or dsRNA-containing of F. solani isolates were found. Prior inoculation of cv. Essex soybean seeds with conidia of dsRNA-free hypovirulent F. oxysporum isolates significantly (P < 0.05) reduced disease severity on cotyledons and hypocotyls, and increased the rate of seedling emergence in field soil, compared to control plants. No significant (P > 0.05) differences were found between dsRNA-containing and dsRNA-free hypovirulent F. oxysporum isolates in their effects on reducing disease severity. Hypovirulent isolates that colonize soybean tissues may play a role in reducing Fusarium seedling disease of soybean in natural soils.     

Interspecies gene transfer provides soybean resistance to a fungal pathogen

Fungal pathogens pose a major challenge to global crop production. Crop varieties that resist disease present the best defence and offer an alternative to chemical fungicides. Exploiting durable nonhost resistance (NHR) for crop protection often requires identification and transfer of NHR‐linked genes to the target crop. Here, we identify genes associated with NHR of Arabidopsis thaliana to Phakopsora pachyrhizi, the causative agent of the devastating fungal disease called Asian soybean rust. We transfer selected Arabidopsis NHR‐linked genes to the soybean host and discover enhanced resistance to rust disease in some transgenic soybean lines in the greenhouse. Interspecies NHR gene transfer thus presents a promising strategy for genetically engineered control of crop diseases.     

Field assessment of plant derivative compounds for managing fungal soybean diseases

Natural plant-derived compounds are currently being explored as alternatives for pest control in sustainable agriculture. This study explored the use of two compounds, sesamol and carbenoxolone, in the management of the fungal soybean disease charcoal rot (Macrophomina phaseolina). Previous studies have determined that sesamol and carbenoxolone compounds significantly inhibited fungal pathogen growth and plant disease in vitro. In order to assess the field efficacy of these compounds for fungal disease control, 2 years of field testing of these compounds have been conducted in southeast Kansas. Field treatments of the compounds sesamol and carbenoxolone at three concentrations, 0, 500 and 1000 microg/ml, were applied foliarly at four distinct plant developmental stages. Treatments were applied to plots in random triplicate array and the experiment was repeated during the 1998 and 1999 growing seasons. Disease assessments were based on visual disease ratings, plant mortality and soybean yield analysis. Data were recorded weekly for each treatment plot and statistically analysed using analysis of variance. Results indicate that sesamol and carbenoxolone treatments significantly decreased disease symptoms (11-12%) and plant mortality (24-28%) while significantly increasing soybean yields (18-38%). These results support that plant-derived compounds can have a significant impact on soybean disease management and yield under field conditions.     

Proteomic Analysis of Differentially Expressed Proteins in Resistant Soybean Leaves after Phakopsora pachyrhizi Infection

Soybean rust caused by Phakopsora pachyrhizi is a destructive foliar disease in nearly all soybean‐producing countries. Understanding the host responses at the molecular level is certainly essential for effective control of the disease. To identify proteins involved in the resistance to soybean rust, differential proteomic analysis was conducted in soybean leaves of a resistant genotype after P. pachyrhizi infection. A total of 41 protein spots exhibiting a fold change >1.5 between the non‐inoculated and P. pachyrhizi‐inoculated soybean leaves at 12 and 24 h postinoculation (hpi) were unambiguously identified and functionally grouped into seven categories. Twenty proteins were up‐regulated and four proteins were down‐regulated at 12 hpi, whereas 18 proteins were up‐regulated and eight proteins were down‐regulated at 24 hpi. Generally, proteins involved in photosynthesis were down‐regulated, whereas proteins associated with disease and defense response, protein folding and assembly, carbohydrate metabolism and energy production were up‐regulated. Results are discussed in terms of the functional implications of the proteins identified, with special emphasis on their putative roles in defense. Abundance changes of these proteins, together with their putative functions reveal a comprehensive picture of the host response in rust‐resistant soybean leaves and provide a useful platform for better understanding of the molecular basis of soybean rust resistance.