谷子赤霉病病菌致病性及抗病性鉴定技术体系的建立

Foxtail millet is one of the most traditional and popular crops in China. Its early maturity and efficient use of available water make it suitable for raising in dry areas. It contains low phytic acid and is rich in dietary fiber, iron, calcium and B vitamins. Moreover, foxtail millet releases sugar slowly in the blood and also diminishes the glucose absorption. These properties make the foxtail millet more attractive and make the whole millet industry more prospective. However, diseases in foxtail millet have become a serious threat to the development of the whole industry. Fusarium ear rot (FER), causing by Fusarium graminearum, is a chronic and serious disease in millet production in China. A study in 2014 showed that FER could significantly reduce yield with an incidence of 40%. In addition to yield losses, FER infected plants could also produce mycotoxins in grain as well as other tissues. The presence of these compounds in food and feeds can be harmful for human and livestock. Growing resistant varieties has long been recognized as an integral part in effectively managing such diseases. So far, researches conferring FER resistance and working toward the breeding of varieties resistant to this disease are rare. To facilitate the breeding of resistant varieties and identify sources of resistance in foxtail millet, we intend to collect the Fusarium isolates from different regions and identify the distribution of pathogens and its relationship with pathogenicity. By analyzing a great number of millet germplasms and varieties, a disease-resistant system will be established. Meanwhile, the resistant sources will be screened. The identification of the resistant sources will provide the resistant parents to develop segregating populations and facilitate mapping of these sources of FER resistance. It will at last lead to accelerating the progress of molecular breeding of resistant varieties.

谷子是我国古老的传统作物，抗旱耐瘠、粮草兼用、营养丰富，发展前景无限广阔。但是谷子病害严重威胁着谷子产业的发展。赤霉病是一种由禾谷镰刀菌引起的谷子新兴病害，它不仅危害着谷子产业的发展，而且赤霉病产生的毒素被食用后会使人畜中毒，影响人类健康，利用抗病品种是最经济有效环保的防治方法。目前谷子赤霉病方面的研究处于起步阶段，拟开展的研究项目对采集自不同地区的镰孢菌进行分离鉴定，明确病原菌种类分布，以及种间致病性差异，从16800份种质资源中选出多份谷子生产上常用的品种和种质资源，进行抗赤霉病鉴定，从而明确谷子赤霉病抗病分级的标准和建立抗病体系，从中筛选出高抗材料，为谷子赤霉病抗性位点的研究筛选出抗性亲本，为今后的分离群体建立、抗性基金的定位以及开发标记等工作奠定基础，加快抗病新品种的选育进程。

我国谷子种植面积占世界的80%以上，但是谷子病害严重威胁着谷子产业的发展。赤霉病是一种由禾谷镰刀菌引起的谷子新兴病害，于2014年才在我国被首次报道且发病率高达40%，它不仅危害着谷子产业的发展，由其产生的毒素被食用后会使人畜中毒，影响人类健康。此外，赤霉病产生的菌丝和孢子可以在秸秆中存活2年以上，结合我国目前少耕免耕、秸秆还田等耕作制度的改变，可以导致其他轮作的作物如小麦、玉米等感染由禾谷镰刀菌引起的茎基部病害。培育和种植抗病品种是目前最经济有效环保的防治方法之一，但是目前谷子赤霉病方面的研究处于起步阶段，菌株的收集、致病力、接种方法和抗性品种的筛选等方面的研究比较匮乏，所以对谷子赤霉病菌的致病性和抗病性鉴定技术体系的建立尤为重要。本资助项目的研究主要分为以下三个方面：第一、对采集自我国主要谷子产区的56个镰孢菌菌株进行分离纯化，通过形态学和测序的方法进行鉴定，确定了危害我国谷子生产的镰刀菌主要是禾谷镰刀菌和木贼镰刀菌两种，并且从产孢能力和致病能力两个方面出发筛选出了强致病菌株，该菌株在接种后的病苗率达到50%；第二、在确定了强致病菌株和借鉴了小麦赤霉病接种方法的基础上，对谷子赤霉病的接种方法进行了改良，经过反复实验确定了谷子赤霉病是花器侵染后通过菌丝逐渐蔓延，在谷子即将开花或少量开花时期对谷子穗部进行孢子喷雾接种最为有效，并制定病害0-5级的分级标准；第三、于2018和2019年在室内和田间对我国谷子200余份材料进行反复接种筛选，最终得到高抗材料4份，高感材料11份，为今后的分离群体建立、抗性基金的定位以及开发标记等工作奠定基础，加快抗病新品种的选育进程。