The blast resistance gene Pik-p, mapping to the Pik locus on the long arm of rice chromosome 11, was isolated by map-based in silico cloning. Four NBS-LRR genes are present in the target region of cv. Nipponbare, and a presence/absence analysis in the Pik-p carrier cv. K60 excluded two of these as candidates for Pik-p. The other two candidates (KP3 and KP4) were expressed in cv. K60. A loss-of-function experiment by RNAi showed that both KP3 and KP4 are required for Pik-p function, while a gain-of-function experiment by complementation test revealed that neither KP3 nor KP4 on their own can impart resistance, but that resistance was expressed when both were introduced simultaneously. Both Pikp-1 (KP3) and Pikp-2 (KP4) encode coiled-coil NBS-LRR proteins and share, respectively, 95 and 99% peptide identity with the two alleles, Pikm1-TS and Pikm2-TS. The Pikp-1 and Pikp-2 sequences share only limited homology. Their sequence allowed Pik-p to be distinguished from Pik, Pik-s, Pik-m and Pik-h. Both Pikp-1 and Pikp-2 were constitutively expressed in cv. K60 and only marginally induced by blast infection.
通过电子图位克隆的方法分离了稻瘟病抗性基因Pik-p，该基因位于水稻11 号染色体Pik 座位上。在目标区间内，日本晴有4个NBS-LRR 基因，而在携带有Pik-p 的品种K60 内，通过存在/缺失的关系排除了其中两个NBS-LRR 基因是候选基因的可能性。另外两个候选基因KP3 和KP4 在K60 中表达。RNAi 实验表明KP3 和KP4 两个基因对Pik-p 的抗病性而言均是必需的，互补实验表明只存在KP3 或只存在KP4 不能产生抗病性，而两者同时存在时就能产生抗性。Pikp-1(KP3) 和Pikp-2(KP4) 均编码CC-NBS-LRR 蛋白，分别与Pikm1-TS 和Pikm2-TS 有95% 和99% 的蛋白同源性。Pikp-1 和Pikp-2 序列只有有限的同源性。通过基因序列可以将Pik-p 与Pik, Pik-s, Pik-m 和Pik-h 区分开来。Pikp-1 和Pikp-2 在K60 内组成性表达，稻瘟病侵染可以少量诱导基因表达。