Durable panicle blast-resistance gene Pb1 encodes an atypical CC-NBS-LRR protein and was generated by acquiring a promoter through local genome duplication
Durable panicle blast-resistance gene Pb1 encodes an atypical CC-NBS-LRR protein and was generated by acquiring a promoter through local genome duplication
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DOI：
10.1111/j.1365-313x.2010.04348.x
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发表时间：
2010-11-01
期刊：
影响因子：
7.2
通讯作者：
Takatsuji, Hiroshi
中科院分区：
文献类型：
--
作者：
Hayashi, Nagao;Inoue, Haruhiko;Takatsuji, Hiroshi
稻瘟病是世界范围内分布最广、危害最大的植物病害之一。育种者已经使用介导真菌小种特异性的“基因对基因”抗性的抗病（R）基因来管理稻瘟病，但是由于稻瘟病真菌的高致病性变异性，抗性容易被破坏。穗瘟1（Panicle blast 1，Pb 1）是来源于籼稻品种莫丹的一个抗稻瘟病基因。Pb 1介导的抗性以抗性持久性和成穗稻瘟病抗性为特征，已被引入到用于商业化栽培的优良品种中。我们通过图位克隆的方法分离了Pb 1基因。它编码一个卷曲螺旋核苷酸结合位点富含亮氨酸重复序列（CC-NBS-LRR）蛋白。Pb 1蛋白序列不同于以前报道的R-蛋白，特别是在NBS结构域，其中的P-环显然是不存在的和一些其他的图案退化。Pb 1位于一个串联重复的60-kb单位，这可能是通过本地基因组复制。铅1+品种的发展过程中，铅1转录水平增加，这种表达模式占他们的成人/穗抗性。启动子：GUS分析表明，基因组复制发挥了至关重要的作用，在铅1的产生，通过放置一个启动子序列上游的编码序列，从而赋予一个铅1特性的表达模式，转录不活跃的“睡眠”抗性基因。我们讨论了可能的决定因素的持久性Pb 1介导的稻瘟病抗性。
Rice blast is one of the most widespread and destructive plant diseases worldwide. Breeders have used disease resistance (R) genes that mediate fungal race-specific 'gene-for-gene' resistance to manage rice blast, but the resistance is prone to breakdown due to high pathogenic variability of blast fungus. Panicle blast 1 (Pb1) is a blast-resistance gene derived from the indica cultivar 'Modan'. Pb1-mediated resistance, which is characterized by durability of resistance and adult/panicle blast resistance, has been introduced into elite varieties for commercial cultivation. We isolated the Pb1 gene by map-based cloning. It encoded a coiled-coil-nucleotide-binding-site-leucine-rich repeat (CC-NBS-LRR) protein. The Pb1 protein sequence differed from previously reported R-proteins, particularly in the NBS domain, in which the P-loop was apparently absent and some other motifs were degenerated. Pb1 was located within one of tandemly repeated 60-kb units, which presumably arose through local genome duplication. Pb1 transcript levels increased during the development of Pb1+ cultivars; this expression pattern accounts for their adult/panicle resistance. Promoter:GUS analysis indicated that genome duplication played a crucial role in the generation of Pb1 by placing a promoter sequence upstream of its coding sequence, thereby conferring a Pb1-characteristic expression pattern to a transcriptionally inactive 'sleeping' resistance gene. We discuss possible determinants for the durability of Pb1-mediated blast resistance.