A novel bacterial blight resistance gene from Oryza nivara mapped to 38 kb region on chromosome 4L and transferred to Oryza sativa L.
A novel bacterial blight resistance gene from Oryza nivara mapped to 38 kb region on chromosome 4L and transferred to Oryza sativa L.
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DOI：
10.1017/s0016672308009786
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发表时间：
2008-10-01
影响因子：
1.5
通讯作者：
Singh, Kuldeep
中科院分区：
文献类型：
--
作者：
Cheema, Kuljit K.;Grewal, Navjit K.;Singh, Kuldeep
水稻白叶枯病是东南亚水稻生产的主要限制因素之一。单独或联合使用主基因的策略仍然是BB管理的最有效方法。目前，已经指定了二十多个基因，但并非所有已知的基因都能有效对抗所有流行的致病型。因此，挑战是继续扩大有效和潜在持久抗性基因的基因库。野生种构成了包括BB在内的抗性基因的重要储存库。发现一个加入的Oryza nivara（IRGC 81825）对印度北方各邦流行的所有7种Xoo致病型具有抗性。O.以水稻品种PR 114与普通野生稻杂交的F_2、BC_2F_2、BC_3F_1和BC_3F_2为材料，对nivara进行了研究。nivara ace。81825使用最毒力的Xoo致病型。对分离后代的遗传分析表明，O. nivara由一个显性基因控制。利用191个多态性SSR标记对F-2群体进行群体分离分析，在4L染色体上发现了一个与BB抗性相关的区域，该区域位于RM 317和RM 562之间，大小约为35 cM。利用30多个多态性SSR标记对BC、F和BC 2F 2后代进行了筛选和基因分型，覆盖了细菌人工染色体（BAC）克隆OSJNBb 0085 C12，并在基于注释基因LOC_Os04g53060和LOC_Os04g53120的STS标记之间定位了抗病基因，其相似性为384 kb。由于定位在4L染色体上的已知Xa基因对所测试的Xoo致病型均无效，因此从O. nivara是新的，暂时命名为Xa 30（t）。已经鉴定了具有最小渐渗区域的纯合抗性BC 3F 3后代。
Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv oryzae (Xoo) is one of the major constraints to productivity in South-East Asia. The strategy of using major genes, singly or in combination, continues to be the most effective approach for BB management. Currently, more than two dozen genes have been designated but not all the known genes are effective against all the prevalent pathotypes. The challenge, therefore, is to continue to expand the gene pool of effective and potentially durable resistance genes. Wild species constitute an important reservoir of the resistance genes including BB. An accession of Oryza nivara (IRGC 81825) was found to be resistant to all the seven Xoo pathotypes prevalent in northern states of India. Inheritance and mapping of resistance in O. nivara was studied by using F-2, BC2F2, BC3F1 and BC3F2 progenies of the cross involving Oryza sativa cv PR114 and the O. nivara ace. 81825 using the most virulent Xoo pathotype. Genetic analysis of the segregating progenies revealed that the BB resistance in O. nivara was conditioned by a single dominant gene. Bulked segregant analysis (BSA) of F-2 population using 191 polymorphic SSR markers identified a similar to 35 centiMorgans (cM) chromosomal region on 4L, bracketed by RM317 and RM562, to be associated with BB resistance. Screening of BC,F, and BC2F2 progenies and their genotyping with more than 30 polymorphic SSR markers in the region, covering Bacterial artificial chromosome (BAC) clone OSJNBb0085C12, led to mapping of the resistance gene between the STS markers based on annotated genes LOC_Os04g53060 and LOC_Os04g53120, which is similar to 384 kb. Since none of the known Xa genes, which are mapped on chromosome 4L, are effective against the Xoo pathotypes tested, the BB resistance gene identified and transferred from O. nivara is novel and is tentatively designated as Xa30(t). Homozygous resistant BC3F3 progenies with smallest introgression region have been identified.