黄淮区粳稻抗稻瘟病基因Pi-ta、Pi-b、Pi54、Pikm的分子检测

利用水稻稻瘟病抗病基因Pi-ta、Pi-b、Pi54 和Pikm的功能标记对2016年山东省水稻中晚熟组区试、机插秧组区试的32个参试品系及连云港农业科学院科企水稻联合体黄淮粳稻区试16个品系进行了分子标记检测,结合稻瘟病抗性接种鉴定,对基因型与表型进行相关性分析。结果表明48个品种中携带Pi-ta、Pi-b、Pi54和Pikm抗性基因的品种数分别为15个、25个、26个和21个,其中鲁资稻7号、连粳14JD24含有4个基因的抗性等位基因,YS-6-6、济稻1号、D400等13个品种分别含有3个基因的抗性等位基因,临稻10号、丰稻2号、天和糯303等8个品种不含抗性等位基因。稻瘟病鉴定结果表明,48份品种中,济稻1号、圣稻072、连粳14JD24等4个品种表现中抗（MR）;临稻10、YS-6-6、圣稻053等26个品种表现中感（MS）;晶稻180、临13-105、圣稻504等15个品种表现感病（S）;H11-15、润农9号、晶稻160表现高感（HS）。Pi-ta、Pi-b、Pi54、Pikm 4个抗性基因已在黄淮区粳稻抗稻瘟病育种中得到广泛应用。其中Pikm与稻瘟病抗性综合指数存在显著相关性（r=0.477 5,P<0.01）。     

水稻广谱抗稻瘟病基因研究进展

稻瘟病是水稻生产中的最严重病害之一,由于稻瘟菌小种的高度变异性,垂直抗性基因难以持续控制稻瘟病的危害,因此,克隆和利用广谱持久抗瘟基因被认为是解决稻瘟病问题最经济有效的策略。本文从广谱抗源的筛选与利用,广谱抗瘟基因的定位、克隆与应用等方面对水稻广谱抗稻瘟病基因研究取得的进展进行了概述,并介绍了广谱抗性分子机理的最新研究进展。基于国内外稻瘟病抗性基因研究的现状及趋势,以及我国丰富的抗瘟水稻种质资源,克隆越来越多的广谱抗瘟基因具有重要的理论与应用价值。     

云南疣粒野生稻稻瘟病抗性

野生稻(Oryza rufipogo)保存有许多栽培稻(O. sativa)不具备或已经消失的优异基因资源, 是扩大栽培稻遗传背景、改良产量与品质、提高抗病虫害及抗逆境能力的重要基因库。疣粒野生稻(O. meyeriana)是中国3种野生稻资源之一, 主要分布在云南。为进一步了解其稻瘟病抗性, 首先利用来自不同稻作区的稻瘟病菌株, 通过注射接种法对疣粒野生稻进行系统的稻瘟病抗性鉴定, 发现疣粒野生稻对接种的所有稻瘟病菌株都感病。进一步采用3'/5' RACE方法, 从疣粒野生稻中克隆了水稻同源基因Pid2和Pid3, 并构建过表达转基因株系对基因功能进行了研究。结果表明, Pid2和Pid3与疣粒野生稻中同源基因间在DNA和氨基酸水平上有较大的序列差异, 过表达转基因的日本晴植株对稻瘟病菌的敏感性与对照相似。推测疣粒野生稻在自然接种条件下, 表现出的抗稻瘟病表型很可能是其旱生叶片结构特征形成了对稻瘟病菌侵染的天然屏障。对控制疣粒野生稻这一类性状基因资源的挖掘和利用, 有利于优良抗性水稻品种的培育。研究结果为疣粒野生稻的研究利用提供了新信息和新思路。     

抗稻瘟病水稻资源抗性基因Pita、Pib、Pi9以及Pikm的分布研究

利用抗稻瘟病水稻资源品种杂交,聚合多个抗性基因是培育持久抗稻瘟病水稻新品种的主要育种途径.利用分子标记技术对水稻抗性资源进行基因型鉴定是分子辅助聚合育种的基础.通过以亚华种业科学院稻瘟病病圃抗病水稻资源为材料,利用特异性分子标记对Pi9、Pita、Pib以及Pikm基因在水稻抗稻瘟病资源的分布进行了鉴定,初步建立了抗性基因数据库.同时对抗性基因及与抗性反应的相关性进行了探讨,结果表明以Pi9为主效基因,同时聚合Pita和Pib抗性基因能提高持久抗稻瘟病能力.     

芽胞杆菌在防治水稻稻瘟病中的应用及生防机制

芽胞杆菌具有人畜安全、不污染环境、病原菌不易产生抗药性、抗逆性强和促进植物生长等优点,是稻瘟病防治上的重要生防菌。芽胞杆菌的生防机制主要包括竞争作用、拮抗作用和诱导抗病性。芽胞杆菌定殖在水稻植株上,产生抗菌活性物质抑制稻瘟病菌的生长,诱导水稻产生抗病性,对水稻植株具有促生作用,可以挽回水稻产量损失。芽胞杆菌可以制备生防制剂用来防治我国南方稻区和北方稻区的稻瘟病危害,在水稻产业的可持续发展中对稻瘟病的生物防治具有指导意义。本文主要综述芽胞杆菌在防治水稻稻瘟病中的应用研究、芽胞杆菌在防治水稻稻瘟病中的生防机制、影响稻瘟病生防芽胞杆菌防效的因素。     

水稻苗期抗稻瘟病基因全基因组关联分析

含抗性基因的水稻品种易被病原菌克服,因此为进一步发掘新的稻瘟病抗性基因,利用水稻多样性群体Ⅱ(RDP-Ⅱ)中的470份种质资源,在湖南省桃江县稻瘟病高发区的自然病圃中进行水稻苗期的抗病性鉴定,并通过全基因组关联分析(GWAS)鉴定稻瘟病的抗性相关位点,最终鉴定出25份苗期抗性较好的品种,可作为抗性育种材料。采用混合线性模型(MLM)对700 000个单核苷酸多态性(SNP)基因型和苗期的稻瘟病表型数据进行GWAS研究,在水稻基因组中鉴定了24个抗性关联位点,除4号和7号染色体外,在其余10条染色体上均有分布。在这些关联位点中,5个位点包含已克隆或定位的6个稻瘟病基因,其余19个位点是新的抗性位点。此外,通过对水稻亚群抗性规律分析发现,热带粳稻亚群的平均抗性水平最高,温带粳稻亚群的平均抗性水平最低。这些研究结果为分子辅助抗稻瘟病育种提供了分子标记,也为后续抗稻瘟病基因的克隆提供了基因组定位信息。     

水稻抗稻瘟病天然免疫机制及抗病育种新策略

稻瘟病是水稻最严重的病害之一,由子囊菌(Magnaporthe oryzae)引起。利用抗病品种是防治稻瘟病最经济、最有效的措施。近年来,稻瘟病已发展为研究植物与病原真菌分子互作机制的模式系统,在水稻与稻瘟菌互作和寄主抗性分子生物学、基因组学和蛋白组学等领域取得了一系列重要的研究成果。文章综述了近年来水稻抗稻瘟病两种天然免疫机制,即病原菌相关分子模式诱导和效应蛋白诱导的抗病机制研究的最新进展,讨论了GWAS、TALLEN、CRISPR和HIGS等基因组研究新方法和新技术在水稻抗病育种中的应用,并对目前稻瘟病抗性机制研究和抗病育种中的问题和挑战进行了探讨和展望。     

国外引进水稻种质资源的稻瘟病抗性基因检测与评价

为了筛选出福建省水稻稻瘟病重发区育种中可利用的新抗性资源,在福建省上杭县对156份外引水稻种质资源进行了2年田间自然诱发鉴定,并对Pi2、Pi9、Pi5、Pi54、Pikm、Pita、Pia和Pib等8个稻瘟病抗性基因做了分子检测。结果表明:156份资源对苗瘟、叶瘟、穗颈瘟和综合抗性表现抗病的分别有10份、14份、29份和26份,且苗瘟抗性级别与叶瘟抗性级别(r=0.816,P<0.01)、苗瘟抗性级别与穗颈瘟抗性级别(r=0.347,P<0.01)、以及叶瘟抗性级别与穗颈瘟抗性级别(r=0.344,P<0.01),均呈极显著正相关。分子标记检测到携带稻瘟病抗性基因Pi9、Pi2、Pi54、Pikm、Pi5、Pib、Pia和Pita的水稻资源分别有1、6、20、22、37、88、101和106份,其中携带稻瘟病抗性基因Pi9和Pi2的水稻资源的抗性表现较好,表现抗病的超过60%,携带其他稻瘟病抗性基因的水稻资源表现抗病的均在50%以下;水稻资源携带0~6个稻瘟病抗性基因,随着携带抗性基因数目增加,抗病率呈上升趋势,综合抗性等级呈下降趋势。进一步研究发现,携带Pi9+Pi5+Pikm+Pia、Pi5+Pib+Pita+Pikm+Pia和Pi2+Pi54+Pib+Pita+Pikm+Pia等3个基因型的水稻资源,稻瘟病抗性较好。最后,筛选了8份稻瘟病抗性较好的材料,提供育种者参考、利用。     

稻瘟病抗性基因Pita和Pib在我国水稻主栽品种中的分布

主效抗稻瘟病基因Pita和Pib在我国很多稻区表现高水平的稻瘟病抗性,被广泛应用于我国的水稻育种和生产.但这2个基因在国内主栽品种中的分布及利用情况一直缺乏详细的资料,致使育种利用上存在着盲目性.本研究利用源于Pita和Pib基因本身的特异性分子标记,结合稻瘟病菌接种鉴定,检测和分析了我国58份水稻主栽品种(杂交稻亲本)的Pita和Pib抗性基因型.结果表明,特籼占25、佳禾早占、密阳46、测64-7等4个籼稻品种携带Pita和Pib 2个基因;籼小占等4个籼稻品种(系)和早丰9号等5个粳稻品种携带抗性基因Pita;绵恢501等5个籼稻品种(系)和粳稻品种武育粳7号、辽粳454携带抗性基因Pib.     

宁夏水稻代表性种质及后代抗稻瘟病基因型分析北大核心CSCD

以96份宁夏水稻代表性种质资源和47份杂交后代为试验材料,采用宁夏稻瘟病菌生理小种人工接种和自然诱发相结合的方法对其进行稻瘟病抗性的大田鉴定和病圃鉴定,评价了每个材料的稻瘟病抗性;同时采用8个主效抗稻瘟病基因的功能标记对上述材料进行抗病基因的分子检测,得到了28个不同的抗稻瘟病基因型,将不同基因型的稻瘟病抗性评价进行了差异显著性分析。结果表明,同时含有Pita、Pib、Pikm、Pikh、Pi9和Pi5共6个抗病基因组成的基因型的水稻材料对稻瘟病的抗性极显著高于其他基因型的抗性。Pita基因单独与Pikm、Pikh、Pi2、Pi5基因聚合时均表现出正向聚合效应,其中Pita与Pikh基因的聚合效应最强。当Pib与Pita+Pikh聚合时,表现出负向聚合效应。这为宁夏地区通过基因聚合方法选育广谱持久抗稻瘟病水稻新品种提供了重要的参考依据。     

水稻稻瘟病抗性基因研究概况

稻瘟病是由稻瘟病菌引起的世界性水稻病害,对水稻生产构成严重威胁。分子标记辅助培育持久抗性品种是目前解决稻瘟病抗病品种感病化问题的有效措施。稻瘟病菌-水稻之间的相互作用机理,DNA分子标记的开发与应用,稻瘟病抗性基因定位、克隆与分离及其功能表达等方面的研究进展在很大程度上影响分子标记辅助育种的进程。就此方面的研究概况作一综述。     

A genome-wide meta-analysis of rice blast resistance genes and quantitative trait loci provides new insights into partial and complete resistance

The completion of the genome sequences of both rice and Magnaporthe oryzae has strengthened the position of rice blast disease as a model to study plant-pathogen interactions in monocotyledons. Genetic studies of blast resistance in rice were established in Japan as early as 1917. Despite such long-term study, examples of cultivars with durable resistance are rare, partly due to our limited knowledge of resistance mechanisms. A rising number of blast resistance genes and quantitative trait loci (QTL) have been genetically described, and some have been characterized during the last 20 years. Using the rice genome sequence, can we now go a step further toward a better understanding of the genetics of blast resistance by combining all these results? Is such knowledge appropriate and sufficient to improve breeding for durable resistance? A review of bibliographic references identified 85 blast resistance genes and approximately 350 QTL, which we mapped on the rice genome. These data provide a useful update on blast resistance genes as well as new insights to help formulate hypotheses about the molecular function of blast QTL, with special emphasis on QTL for partial resistance. All these data are available from the OrygenesDB database.     

Evaluation of Rice Cultivars under Greenhouse Conditions for Adult-Plant Resistance to Pyricularia oryzae

Six rice cultivars showing various types of resistance or susceptibility to Pyricularia oryzae in the field were compared under controlled environmental conditions. The resistance of the cultivars with adult-plant resistance was race-specificat early growth stage. On all cultivars tested, blast infection became increasingly reduced on either leaves of adult plants or older leaves, as observed in rice plants of different leaf stages infected with different individual races. Their increase inhost resistance was marked by an apparent transition in infection type and reduced blast severity depending on leaf age and developmental stage of plants. The ranking of disease severity of the adult-plantresistant cultivars to different races was constant during plant development, whereas that of the susceptible cultivars was differential. It is suggested that different degrees of resistance in rice cultivars may exist in seedlings and be consistently maintained during plant development, probably becoming more distinct as rice plants mature.     

Blast resistance in rice: a review of conventional breeding to molecular approaches

Blast disease caused by the fungal pathogen Magnaporthe oryzae is the most severe diseases of rice. Using classical plant breeding techniques, breeders have developed a number of blast resistant cultivars adapted to different rice growing regions worldwide. However, the rice industry remains threatened by blast disease due to the instability of blast fungus. Recent advances in rice genomics provide additional tools for plant breeders to improve rice production systems that would be environmentally friendly. This article outlines the application of conventional breeding, tissue culture and DNA-based markers that are used for accelerating the development of blast resistant rice cultivars. The best way for controlling the disease is to incorporate both qualitative and quantitative genes in resistant variety. Through conventional and molecular breeding many blast-resistant varieties have been developed. Conventional breeding for disease resistance is tedious, time consuming and mostly dependent on environment as compare to molecular breeding particularly marker assisted selection, which is easier, highly efficient and precise. For effective management of blast disease, breeding work should be focused on utilizing the broad spectrum of resistance genes and pyramiding genes and quantitative trait loci. Marker assisted selection provides potential solution to some of the problems that conventional breeding cannot resolve. In recent years, blast resistant genes have introgressed into Luhui 17, G46B, Zhenshan 97B, Jin 23B, CO39, IR50, Pusa1602 and Pusa1603 lines through marker assisted selection. Introduction of exotic genes for resistance induced the occurrence of new races of blast fungus, therefore breeding work should be concentrated in local resistance genes. This review focuses on the conventional breeding to the latest molecular progress in blast disease resistance in rice. This update information will be helpful guidance for rice breeders to develop durable blast resistant rice variety through marker assisted selection.     

Comparison of rice lines derived through anther culture and the pedigree method in relation to blast (Pyricularia grisea Sacc.) resistance

Crosses were made between Fanny (highly susceptible to blast) and 11 cultivars differing in blast resistance. Using the pedigree method (PM) segregating generations were evaluated and selected for blast resistance. Via anther culture (AC), doubled-haploids were obtained from F₁ plants and from F₂ blast-susceptible plants. Pedigree and anther culture-derived lines were planted together and evaluated for blast resistance under rainfed conditions at the Santa Rosa Experiment Station, Villavicencio, Colombia. The principal objective was to compare PM and AC in terms of their efficiency in producing rice lines resistant to blast. Results of a stratified analysis showed an association between method and blast resistance. Results of the logit-model analysis showed that AC produced a significantly (P=0.0001) higher proportion of lines with initial blast resistance (leaf- and neck-blast reaction 4) than did PM across all cross types. Stable blast resistance was assessed based on field performance over 3 years. AC was superior to PM in generating stable resistance for only some cross types. Consequently, with a few exceptions, AC can be used as effectively as PM to develop rice cultivars resistant to blast, with savings in time and labor. Additionally, blast-resistant lines were obtained either by the pedigree method or by anther culture from crosses between blast-susceptible cultivars (Fanny/CICA4 and Fanny/Colombial). This excludes somaclonal variation as a possible mechanism responsible for this resistance and suggests that a recombination of minor genes could have occurred and was fixed through either method. However, the stability of the resistance was greater in pedigree-derived lines. The implications of these findings for rice blast-resistance breeding are discussed.     

Genome‐wide association study identifies an NLR gene that confers partial resistance to Magnaporthe oryzae in rice

Because of the frequent breakdown of major resistance (R) genes, identification of new partial R genes against rice blast disease is an important goal of rice breeding. In this study, we used a core collection of the Rice Diversity Panel II (C‐RDP‐II), which contains 584 rice accessions and are genotyped with 700 000 single‐nucleotide polymorphism (SNP) markers. The C‐RDP‐II accessions were inoculated with three blast strains collected from different rice‐growing regions in China. Genome‐wide association study identified 27 loci associated with rice blast resistance (LABRs). Among them, 22 LABRs were not associated with any known blast R genes or QTLs. Interestingly, a nucleotide‐binding site leucine‐rich repeat (NLR) gene cluster exists in the LABR12 region on chromosome 4. One of the NLR genes is highly conserved in multiple partially resistant rice cultivars, and its expression is significantly up‐regulated at the early stages of rice blast infection. Knockout of this gene via CRISPR‐Cas9 in transgenic plants partially reduced blast resistance to four blast strains. The identification of this new non‐strain specific partial R gene, tentatively named rice blast Partial Resistance gene 1 (PiPR1), provides genetic material that will be useful for understanding the partial resistance mechanism and for breeding durably resistant cultivars against blast disease of rice.     

Breeding and application of Jiafuzhan, a new elite early indica rice cultivar in China

After 20 years of dedicated research,Jiafuzhan has been successfully developed under the new technologies in breeding high-quality early indica rice cultivars.Its rice quality has almost reached the A-level Editable Rice of Agriculture Department of China,and its average production reaches 400-500 kg/(666.7 m2).This new cultivar also has other characteristics such as enhanced resistance of blast and fallen,steady productivity,and strong adaptability.Jiafuzhan has been put into production of over 11.4×104 hm2 in Fujian Province and has been introduced and extended in other Provinces like Jiangxi,Guangdong,and Guangxi,China.The successes of breeding Jiafuzhan is a solution to the existing perennial problems in the rice industry,such as poor grain quality of big-grain rice and early indica rice,low productivity,and poor blast resistance of elite rice.