AB462324

Annotated Information

Function

常规信息

Pik-m 是稻瘟病抗性位点Pik 上的一个主效抗病等位基因，供体是Tsuyuake

基因的定位

Pi-km 初步定位于水稻第11 染色体长臂近末端区域，SSR 标记RM254 和RM144 之间，遗传距离分别是13.4cM 和1.2cM；通过生物信息学分析，发展新的分子标记，最终精细定位在BAC克隆OSJNBa0036K13 内的84kb区间内(Li et al., 2007)。

基因克隆与生物学功能分析

序列分析和遗传互补实验表明，Pi-km 是由两个紧密连锁的具有独立功能NBS-LRR类基因(Pikm1-TS 和Pikm2-TS)组成。其中，Pikm1-TS 包含有62bp 5'-UTR、3432bp 编码区、2个内含子(119bp, 2769bp)和190bp 3'-UTR；Pikm2-TS 与Pikm1-TS 不同源，包含109bp 5'-UTR、3066bp 编码区、1个内含子(163bp)和283bp 3'-UTR(Ashikawa et al., 2008)。 Pikm1-TS 和Pikm2-TS 的编码产物均是NBS-LRR类抗病蛋白，长度分别为1143aa和1021aa。他们在结构上有些小的差异：Pikm1-TS 氨基端发现有nT基序，属于CC结构，而Pikm2-TS 虽也发现有nT基序，但未发现有CC结构；Pikm1-TS 羧基端有非LRR结构，而Pikm2-TS 没有(Ashikawa et al., 2008)。

分子标记辅助选择育种

利用抗稻瘟病基因Pib 自身序列及其等位的感病基因序列建立的分子标记结合运用，可有效地从水稻种质资源中快速而准确地选择出抗稻瘟病基因Pib，并能在分离世代群体中选择出含抗稻瘟病基因Pib 的纯合单株(刘洋等, 2008)。 Link = [1]|

Expression

The Pib gene was isolated by a map-based cloning strategy. The deduced amino acid sequence of the Pib gene product contains a nucleotide binding site (NBS) and leucine-rich repeats (LRRs); thus, Pib is a member of the NBS-LRR class of plant disease resistance genes. Interestingly, a duplication of the kinase 1a, 2 and 3a motifs of the NBS region was found in the N-terminal half of the Pib protein. In addition, eight cysteine residues are clustered in the middle of the LRRs, a feature which has not been reported for other R genes. Pib gene expression was induced upon altered environmental conditions, such as altered temperatures and darkness.【3】 Link = [2]|

Evolution

Gene pyramiding is considered one of the most effective strategies for achieving durable resistance against blast disease (Magnaporthe oryzae B. Couch) in rice (Oryza sativa L.), although few studies have evaluated the combining effect of the resistance genes.the development of pyramided lines with two major blast resistance genes, Pish and Pib, and the evaluation of the combining effect of them. The two genes pyramided lines were selected from the progenies of a cross between one near isogenic line (NIL), which harbours Pish, and another NIL, which harbours Pib, in the genetic background of blast susceptible variety, CO 39. The presence of the resistance genes was confirmed by DNA markers linked to them. To obtain DNA markers for Pish, we genetically mapped the Pish locus. We confirmed the additive effect of Pish and Pib in the pyramided lines by their reaction patterns to blast isolates, suggesting the potential availabilities of the combinations of these genes. In addition, we provide DNA markers linked to Pish for marker aided selection in rice blast resistance breeding.【1】Link = [3]|

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