IRBB21(Xa21)对广东稻白叶枯病菌5个小种的抗性反应

测定携有Xa21抗性基因品种IRBB21对广东省稻白叶枯病菌Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ5个小种的抗性反应。结果表明,IRBB21抗Ⅰ、Ⅱ、Ⅲ,不抗Ⅳ和Ⅴ;以IR24为遗传背景育成的分别含Xa1、Xa2、Xa3、Xa4、xa5、Xa7、xa8、Xa10、Xa11、xa13、Xa14等单基因的近等基因系对我省稻白叶枯病菌优势小种Ⅳ和强致病力小种Ⅴ的抗性反应表明,只有IRBB5和IRBB7抗病,IRBB1、IRBB2、IRBB3、IRBB4、IRBB8、IRBB10、IRBB11、IRBB13、IRBB14均感染。     

水稻对稻瘟病抗性的遗传研究——福建主要籼稻抗源的基因分析

 本文研究了5个水稻抗瘟品种对稻瘟病稳定菌系81090A或81278的抗性遗传。结果表明,在以感病品种矮脚南特或竹广22号为杂交亲本之一的情况下,对81090A菌系的抗性,谷龙13、双抗77021受2对显性重复基因控制,双抗77005受1对显性上位基因和1对隐性基因控制;梧农1号受2或3对显性重复基因控制;双抗77003受1或2对显性上位基因和1对隐性基因控制。对81278菌系的抗性,梧农1号、双抗77003由1对显性上位基因和1对隐性基因支配;谷龙13由1对显性基因,或1对显性上位基因和1对隐性基因支配;双抗77021由1对显性上位基因和1对隐性基因,或2对显性重复基因支配。谷龙13与双抗77021对81090A菌系的反应,似为同质抗性;谷龙13与双抗77003对81278菌系的反应为异质抗性。可采用回交或其它杂交方式将这些抗病基因导入高产品种和杂交水稻三系中,在杂交组合的选趣上,应注意抗源亲本及其它亲本的选择。     

水稻白叶枯病抗性杂种优势

 本试验采用双列式杂交方法,观察了以IR₂₆、IR₃₆等为代表的抗性品种的杂交优势。结果表明:杂交组合F₁代在分蘖末期抗性无优势,穗期抗性优势明显;F₂代两期鉴定正负向均有优势;F₁和F₂代均表现出正负向完全显性,部份显性,少数组合无显性。其中大都属于部份显性。优势指数分析也证明,对抗性亲本,优势指数d ≥ 1;对感病亲本,优势指数d<1。抗感品种杂交,其子代的抗性一般界于双亲值之间。这种优势可依亲本的抗性进行预测。     

水旱两种栽培模式下海南山栏稻对白叶枯病抗性鉴定与评价

为研究山栏稻对白叶枯病抗性,本试验以17个山栏稻品种为材料,在大田与温室大棚中同时种植,于大田中观察山栏稻在水、旱两种栽培模式下对海口当地白叶枯病菌的自然抗性并测产;在温室中检测水、旱两种栽培模式下山栏稻对菲律宾白叶枯病菌小种PXO99(P6)、PX145(P7)的抗性;并以基因功能性标记检测其抗性基因,分析各指标与抗病性的关系。结果表明,大田环境下17个供试品种中有12个品种在水作栽培模式下感病指数高于旱作,有10个品种水作栽培模式下产量比旱作高。温室中用P6接种山栏稻,水作模式下仅有1个品种表现抗病,8个品种感病;旱作模式下2个品种表现抗病,3个品种感病。接种P7,水作时表现抗病和感病的品种数量分别为7个和2个;旱作时表现抗病的品种高达9个,仅1个品种感病。供试品种中有16个品种含有Xa1抗病基因,4个品种含有Xa27抗病基因,所有品种均不含xa13、Xa21抗病基因。因此认为,山栏稻对海口当地白叶枯病菌小种以及菲律宾白叶枯病菌小种都有一定抗性,且抗性受栽培条件的影响,山栏稻旱作时抗性强于水作。     

水稻抗白叶枯病近等基因系对华南菌系的抗性研究

 测定分析了以IR24或Milyang23为轮回亲本构建的水稻抗白叶枯病近等基因系对华南稻白叶枯病菌的抗性。结果显示:携有不同抗性基因的近等基因系,其抗性有些有明显差异,有些又表现相同或类似,说明不同的抗性基因,其抗性有的一样,有的不一样;同一抗性基因在IR24和Milyang23不同遗传背景下,抗性反应有的一致,有的则截然相反,证明抗性表达受遗传背景影响;参试近等基因系大部分对华南的主要致病菌系Ⅳ型菌和Ⅴ型菌感病,仅有IRBB5、LRBB7和IRBB205对这2个菌系都抗,IRBB4和IRBB204抗其中之一的Ⅳ型菌,IRBB203单抗Ⅴ型菌;xa5和Xa4基因抗性较好且抗性表达不受遗传背景影响,携有这些基因的近等基因系推荐应用于华南稻白叶枯病防治。     

小麦抗源对条锈病的抗性遗传研究初报

1983—1985年在北京进行了洛夫林10号等15个国内小麦主要抗源成株期对条锈病的抗性遗传研究。供试抗源分别与感病品种铭贤169杂交,用条中25号小种的单孢子菌系在田间对各组合的亲本、F_1、F_2和F_3代进行接种鉴定。试验结果表明,洛夫林10号、洛夫林13号、洛夫林18号、阿芙乐尔、山前麦、NS2625和抗引655等7个抗源的抗性系由1对显性和1对隐性基因所控制;高加索和F16-71两个抗源的抗性由两对显性基因控制;保加利亚10号的抗性由两对隐性基因控制;HWY1775的抗性由1对完全显性基因控制。初步看出,F33-70、9D-27-2、48111和无芒4号等4个抗源各携带两对抗性基因。供试抗源所携带基因的异同需进一步研究。     

蚕豆赤斑病抗性的主基因+多基因遗传分析

赤斑病是世界蚕豆产区的主要病害,严重威胁蚕豆安全生产。为明确蚕豆赤斑病的抗性遗传规律,本研究用赤斑病抗性较好的蚕豆品种‘通蚕鲜8号’、‘启豆2号’分别与高感赤斑病蚕豆品种‘成胡10号’、‘成胡14号’配制杂交组合,采用主基因+多基因混合遗传模型方法对2个组合6世代(P_1、P_2、F_1、F_2、BCP_1、BCP_2)的赤斑病抗性进行了遗传分析。结果表明,蚕豆对赤斑病的抗性最适合遗传模型为E-0(两对加性-显性-上位性主基因+加性-显性-上位性多基因)。两对赤斑病抗性的主基因加性效应值在2个组合中分别为-40.43、2.16和-36.31、-3.86,显性效应值分别为-15.22、-15.72和-5.98、-6.48。2个组合的主基因遗传率在BCP_1、BCP_2、F_2中分别是19.05%、51.99%、70.90%和19.29%、52.13%、77.35%,多基因遗传率分别为0、0、19.9%和0、0、21.06%。本试验条件下,蚕豆品种‘通蚕鲜8号’、‘启豆2号’对赤斑病抗性由2个主效基因控制,同时受多基因修饰作用,环境对其抗性影响较小。感病亲本对后代抗病性的负向影响较大,在育种实践中需适当提高感病亲本的抗病性,以提高后代的抗性水平。     

江苏省水稻品种对水稻细菌性条斑病抗性鉴定及评价

为明确江苏省水稻条斑病菌致病力分化状况和不同类型水稻品种对条斑病抗感特性,在孕穗期采用针刺接种法对徐淮稻区2007—2009年采集分离获得的45株条斑病菌进行致病力测定,根据病原菌在6个水稻鉴别品种IRBB4、IRBB5、IRBB14、IRBB21、IR24和金刚30上的抗感反应划分致病型,从中选择具有代表性的3种不同致病型条斑病菌,并鉴定了240个不同类型的水稻品种对条斑病的抗感性。根据菌株在鉴别品种上的抗感反应将供试菌株划分为8个致病型,其中优势致病型为C3致病型,所占比例为35.5%;大多数菌株与鉴别品种间表现出弱互作关系,少数菌株表现出强互作关系。粳稻品种对条斑病的抗性明显高于籼稻,但常规粳稻和杂交粳稻对强致病力菌抗性比例仅为59.8%和37.5%。表明水稻细菌性条斑病流行仍具有潜在的威胁。     

玉米自交系心叶期对亚洲玉米螟抗性遗传规律的研究初报

不同抗螟性亲本所组配的F_1代在玉米心叶期,对亚洲玉米螟 Ostrinis furnacalis(Guenée)抗性研究表明,玉米抗螟牲为数量遗传,亲本抗性在杂种后代中具有累加效应,杂种的抗性与双亲平均抗性呈高度正相关。中等以上抗性亲本组配的 F_1代为抗螟型。而以中抗系组配杂种时,不论父本或母本,只要一个亲本为感螟系,则 F_1代均为感螟型。不同水平抗性亲本组配的正反交组合 F_1代差异极显著。     

杂交水稻叶瘟抗性杂种优势的遗传分析

 本文用水稻7个不育系、7个恢复系及其按NCⅡ设计配制的49个杂交组合,在4个指标上研究了杂交水稻叶瘟抗性的杂种优势和遗传。结果表明:杂交水稻的叶瘟抗性不仅具有较强的杂种优势,而且在组合间变异很大;叶瘟抗性遗传力高,其受加性和非加性遗传共同控制,但加性遗传明显较为重要,源于恢复系的加性效应明显相对重要于不育系的加性效应;亲本叶瘟抗性与其一般配合力效应呈显著或极显著正相关;缙恢1号具有较好的一般配合力效应和较大的特殊配合力方差,可作为优良抗病亲本加以利用,K42A、K40A、多恢1号、成恢149具有较好的一般配合力效应和较小的特殊配合力方差,在抗稻瘟育种中具有较大利用价值。讨论认为:在抗叶瘟育种中,对亲本的抗性评鉴和选育抗病亲本尤其是恢复系至关重要,但不能以此忽略对杂交组合的抗性评鉴。     

Gene-for-gene relationships between rice and diverse avrBs3/pthA avirulence genes in Xanthomonas oryzae pv. oryzae

The interactions between Xanthomonas oryzae pv. oryzae (Xoo) and rice are controlled in a gene-for-gene manner. In this study, a 359 bp DNA fragment of the avrXa3 gene containing three nuclear localization signal (NLS) motifs present in all members of the avrBs3/pthA family was used as a probe to screen a genomic library of the JXOIII strain of Xoo. The results demonstrated that diverse members of the family exist in the pathogen genome. The avrBs3/pthA genes occurred at isolated individual portions or in clusters. The positive avr gene clones were transferred into the virulent recipient PXO99^A. Pathogenicity tests in near isogenic lines of rice confirmed that four resistance (R) genes ( Xa2 , Xa3 , xa5 and xa8 ) matched the four avr genes ( avrXa2 , avrXa3 , avrxa5 and avrxa8 ) in the genome of Xoo strain JXOIII. The avrBs3/PthA -like gene (1·7 kb) present in cosmid p54, may specifically interact with the Xa3 gene present in IRBB3, and is designated avr/pthA3 . Sequencing indicated that there are only 1·5 copies of the 102 bp repeat unit in avr/pthA3 . Alignment of the twelfth and thirteenth amino acids in the repetitive units encoded by this gene with those in other representatives of the AvrBs3 family revealed a unique repeat arrangement which might contribute to variation in the avirulence genes in Xoo. The parental rice line IR24 was found to contain several R genes for resistance to Xoo bacterial blight.     

水稻白叶枯病菌北方菌株的分子鉴别和致病型分析

为了阐明水稻白叶枯病菌(Xanthomonas oryzaepv.oryzae,Xoo)北方菌株的毒性组成,对2008年和2009年从辽宁、吉林、河北、山东稻区采集的103个菌株进行了PCR分子鉴定,并利用一套水稻抗白叶枯病近等基因系作为鉴别品种,进行了致病性测定。结果表明,用3种不同引物对测定菌株基因组进行PCR扩增,均可以鉴别出与Xoo代表菌株完全一致、而与水稻条斑病菌明显不同的特异性扩增片段带型。6个水稻鉴别品种对测定菌株的感病反应明显不同,抗病性强弱依次为IRBB5IRBB13IRBB3IRBB14IRBB2IRBB24。103个菌株对6个水稻鉴别品种表现出毒力多样性,92个菌株(89.32%)表现与9个标准小种(R1~R9)代表菌株相同的致病型,其中36个R5和R8菌株为优势菌株,9个菌株为对6个水稻品种都致病的R9强毒力菌株;此外,新发现了其余11个菌株(10.68%)具有7种新的致病型(R10~R16)。     

水稻对白叶枯病强毒菌系Ⅴ型菌的抗性研究

作者报道了水稻对广东白叶枯病强毒菌系Ⅴ型菌抗性研究与抗源筛选评价结果。从1076份国内外水稻种质资源中筛选出29份抗病材料,占2.70％。其中IRBB7等5份具有广谱、高抗兼较好农艺性状。由日本和国际水稻所鉴定的14个抗性基因中Xa-3、xa-5、Xa-7、xa-13等抗Ⅴ型菌。抗Ⅴ型菌材料多数兼抗其它菌型,但亦有一些不抗Ⅳ型菌,表明菌型与品种间有强烈互作效应。水稻对Ⅴ型菌抗性与其类型有关,梗稻与籼稻、糯稻与粘稻、国外稻与国内稻比较,抗病率均以前者为高。     

Identification and molecular mapping of the rice bacterial blight resistance gene allelic to <Emphasis Type="Italic">Xa7</Emphasis> from an elite restorer line Zhenhui 084

Rice bacterial blight (BB), caused by Xanthomonas oryzae pv. Oryzae (Xoo), is a serious disease in rice production worldwide. Rice cv. Zhenhui 084, a newly developed strong indica restorer line, exhibits high resistance to most of the Philippine races of BB and has been widely used in rice hybrids in China; however, the resistance gene has not yet been cloned. Here, we show that the resistance of Zhenhui 084 to Xoo strains is similar to that of IRBB7 containing Xa7, a durable and broad resistance dominant gene for BB. To map the resistance gene in Zhenhui 084, a F₂ population with 331 highly susceptible individuals derived from a cross between Chenghui 448 and Zhenhui 084 was built. We finely mapped the target R gene to a region between two proximal markers RM20576 and MY4 in rice chromosome 6. A marker-based physical map of chromosome six was used to construct the contig covering the genomic region between two markers RM20576 and MY4. The target gene was assumed to be in an interval of approximate 200 kb, in which 16 candidate genes were predicted. Our findings will greatly facilitate the isolation and characterisation of the target R gene allelic to Xa7. Additionally, two PCR-based markers, tightly linked to the target R gene locus, will be a useful tool for the marker-assisted selection of the target R gene allelic to Xa7 in breeding programmes.     

Dynamics of Xanthomonas oryzae pv. oryzae Populations in Korea and Their Relationship to Known Bacterial Blight Resistance Genes

ABSTRACT Developing resistant cultivars requires an understanding of the dynamics of the pathogen populations as well as the genetics of host resistance. Bacterial leaf blight (BB), caused by the vascular pathogen Xanthomonas oryzae pv. oryzae, has become one of the most devastating diseases of rice. We demonstrate here the quantitative analyses of responses of near-isogenic lines carrying various BB resistance (R) genes and R-gene combinations against 16 X. oryzae pv. oryzae isolates representing Korean BB pathotypes. The estimated main effects of each R gene against the 16 isolates identified prominent differences in BB pathotypes between Korea and other countries. Three major aspects of our quantitative observations and statistical analysis are (i) strong and broad resistance of xa5; (ii) independent and additive genetic actions of Xa4, xa5, and Xa21 under digenic or trigenic status; and (iii) a strong quantitative complementation effect contributed by the functional alleles of Xa4 and Xa21. We conclude that the pyramid line containing genes Xa4, xa5, and Xa21 would be the most promising and valuable genotype for improving Korean japonica cultivars for BB resistance.     

137份云南省地方稻抗白叶枯病多菌系多基因鉴定

为选育水稻抗性品种和发掘抗白叶枯病基因,以来自中国、日本和菲律宾的9株革兰氏阴性菌黄单胞菌水稻变种Xanthomonas oryzae pv. oryzae菌株为供试菌株评价137份云南省地方稻种质资源对白叶枯病菌的抗性,同时检测供试材料中含14个已克隆抗白叶枯病基因的情况。结果显示,供试材料中至少对1株黄单胞菌水稻变种菌株有抗性的材料有104份,抗1、2、3、4、5、6、7、8和9株黄单胞菌水稻变种菌株的材料分别有25、19、14、19、11、6、5、2和3份;其中白杂一号、珍白18、麻旱谷、老来红、晋糯、香谷、毫冷薅、齐头蚂蚱谷、九谷和来之不易10份材料抗谱较广。大部分抗性材料携带1～7个白叶枯病抗性基因或其同源基因,未检测到含有Xa7、xa13、Xa21和Xa45(t)基因或其同源基因的材料。供试材料携带的抗性基因数量与抗性水平均呈极显著相关。     

云南疣粒野生稻抗白叶枯病鉴定及叶片组织学观察

 本研究采用水稻白叶枯病菌强致病性代表菌株,评价了云南省自然分布的疣粒野生稻代表生态居群18份材料的抗病性,观察叶片组织学结构,初步分析了疣粒野生稻的抗性基因。结果表明,16份材料表现中抗、高抗甚至免疫;9份材料对4个菌株的抗性有一定差异;同时发现云南地方代表菌株X1和CN9404的致病性比C1和BD8438强。叶片组织学结构表明,高抗材料与感病的栽培稻米泉黑芒都无蜡质层,二者的叶肉组织、薄壁细胞和表皮细胞相同,表皮毛、维管束、厚壁组织等的差异也不明显,不足以引起抗病性差异。疣粒野生稻高抗或免疫白叶枯病并非借助其特殊叶片结构的物理作用,而主要是抗病基因的作用。参试疣粒野生稻中没有与Xa1、Xa21同源的基因,加之独立进化,推断其具有新的优异抗白叶枯病基因,值得深入研究和发掘利用。     

Inheritance of resistance to bacterial blight in 21 cultivars of rice

ABSTRACT Genetic analysis for resistance to bacterial blight (Xanthomonas oryzae pv. oryzae) of 21 rice (Oryza sativa L.) cultivars was carried out. These cultivars were divided into two groups based on their reactions to Philippine races of bacterial blight. Cultivars of group 1 were resistant to race 1 and those of group 2 were susceptible to race 1 but resistant to race 2. All the cultivars were crossed with TN1, which is susceptible to all the Philippine races of X. oryzae pv. oryzae. F(1) and F(2) populations of hybrids of group 1 cultivars were evaluated using race 1 and F(1) and F(2) populations of hybrids of group 2 cultivars were evaluated using race 2. All the cultivars showed monogenic inheritance of resistance. Allelic relationships of the genes were investigated by crossing these cultivars with different testers having single genes for resistance. Three cultivars have Xa4, another three have xa5, one has xa8, two have Xa3, eight have Xa10, and one has Xa4 as well as Xa10. Three cultivars have new, as yet undescribed, genes. Nep Bha Bong To has a new recessive gene for moderate resistance to races 1, 2, and 3 and resistance to race 5. This gene is designated xa26(t). Arai Raj has a dominant gene for resistance to race 2 which segregates independently of Xa10. This gene is designated as Xa27(t). Lota Sail has a recessive gene for resistance to race 2 which segregates independently of Xa10. This gene is designated as xa28(t).     

Virulence profiling of <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis> isolates,causing bacterial blight of rice in India

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae (Xoo), remains a major production constraint in rice cultivation especially in irrigated and rainfed lowland ecosystems in India. The pathogen is highly dynamic in nature and knowledge on pathotype composition among the Xoo population is imperative for designing a scientific resistance breeding program. In this study, four hundred isolates of Xoo collected from diverse rice growing regions of India were analyzed for their virulence and genetic composition. Virulence profiling was carried out on a set of differentials consisting of 22 near isogenic lines (NILs) of IR24 possessing different BB resistance genes and their combinations along with the checks. It was observed that different NILs possessing single BB resistance gene were susceptible to about 59–94% of the Xoo isolates except IRBB 13 (containing BB resistance gene xa13), which showed susceptibility to about 35% of the isolates. Based on the reaction of the Xoo isolates on the differentials, they were categorized into 22 pathotypes. Among the 22 pathotypes, IXoPt-1 and IXoPt-2 were least virulent and IXoPt # 18–22 were highly virulent. Pathotype IXoPt-19 which was virulent on all single BB resistance genes except xa13 constituted the major pathotype (22.5% isolates) and was widely distributed throughout India (16 states). This was followed by pathotype IXoPt-22 (17.25%) which was virulent on all the NILs possessing single BB resistance genes. Molecular analysis was carried out using two outwardly directed primers complementary to sequence of IS1112, a repetitive element of Xoo. A high level of genetic polymorphism was detected among these isolates and the isolates were grouped into 12 major clusters. The data indicated complex nature of evolution of the Xoo pathotypes and there was no strong correlation between pathotypes and genetic clusters as each genetic cluster was composed of Xoo isolates belonging to different pathotypes. The study indicated that none of the single BB resistance genes can provide broad spectrum resistance in India. However, two-gene combinations like xa5 + xa13 and different 3 or 4 genes combination like Xa4 + xa5 + xa13, Xa4 + xa13 + Xa21, xa5 + xa13 + Xa21 and Xa4 + xa5 + xa13 + Xa21 are broadly effective throughout India.