Pib ，水稻稻瘟病抗性基因，来自品种"BL1"，对日本大多数稻瘟病菌小种有抗性，对中国的菌株ZB13 和ZC15 也表现抗病反应。
Pib 基因定位于水稻第2 染色体长臂近末端区域，与RFLP标记RZ123, C379, C2782B 等连锁(Miyamoto et al., 1996; Monna et al., 1997)。 Pib 基因定位于水稻第2 染色体上RFLP 标记S1916 和G7030 之间，遗传距离分别为0.015 cM 和0.045 cM，并与RFLP 标记G7010, G7021 和G7023 共分离(Wang et al., 1999)。对应于日本晴测序图谱的位置(5'-3')在35109965 - 35109117 区间(Rice Genome Annotation Project: TIGR version6)。
Pib 基因属于"NBS-LRR"类抗病基因，包含有4个内含子(164 bp, 810 bp, 1340 bp, 308 bp)，全长cDNA由306bp 的5'非翻译区(UTR, untranslated regions)、3753bp 的ORF 和229bp 的3'非翻译区等组成。Pib 编码一个由1251 个氨基酸组成的蛋白产物，该产物包含一个核苷酸结合位点(nucleotide binding site, NBS)和17个富亮氨酸重复序列(leucine-rich repeats, LRRs)，其中，氨基端的NBS 区存在激酶1a, 2 和3a 结构域单位，LRRs 中部有8 个成簇的半胱氨酸残基(Wang et al., 1999)。 Pib 基因会因环境条件的变化而诱导调控，如温度、光照等条件的改变都将影响该基因的表达(Wang et al., 1999)。
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 = |
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 = |
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 = |
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