长江下游粳稻稻瘟病广谱抗性基因组合模式分析

[目的]基因聚合是实现水稻稻瘟病广谱抗性的有效途径之一.通过构建粳稻背景下不同双基因聚合系,利用长江下游粳型稻瘟病菌(Magnaporthe oryzea)菌株评价其抗性效应并解析其抗性效应产生的构成因子,为长江下游粳稻抗稻瘟病育种提供广谱抗性基因组合模式和种质资源.[方法]以粳稻07GY31为背景的Piz基因座不同复...

Construction and Analysis of Broad-Spectrum Resistance Gene Combination Pattern for Japonica Rice in Lower Region of the Yangtze River,China

【Objective】Gene pyramiding is one of the most effective ways to achieve broad-spectrum resistance against Magnaporthe oryzae. The objective of this study is to construct a set of polygene pyramiding lines (PPLs) under the background of japonica rice, to evaluate their resistance performances and analysis the components of their resistance effects using M. oryzae strains collected from lower region of the Yangtze River, China, thus providing broad-spectrum resistance gene combination pattern and germplasm resources for japonica rice resistance breeding in lower region of the Yangtze River, China. 【Method】Monogenic lines with multiple alleles of the Piz locus (Pigm, Pi40, Pi9, Pi2, Pizt and Piz) with the background of japonica rice 07GY31 as the backbone, crossed with other broad-spectrum resistance gene Pi1, Pi54 and Pi33, respectively using the incomplete NCII mating design. A total of 18 different PPLs were constructed using marker-assisted selection (MAS) and agronomic traits screening. Artificial inoculation assays at seedling and heading stage with 109 representative M. oryzae strains collected from lower region of the Yangtze River, combined with natural induction identification under multiple field environments were conducted to evaluate the resistance performances of different PPLs, and to analyze the component factors of the resistance effects of the PPLs. 【Result】Genotyping by sequencing (GBS) analysis shows that the constructed PPLs all have a high background recovery rate, which was ranging from 97.08% (PPL ^Piz/Pi33) to 99.08% (PPL^Pigm/Pi1), indicated that the genetic background of all PPLs was almost fully identical to that of the recurrent parent 07GY31. The seedling blast and panicle blast resistance levels of most PPLs were significantly higher than those of monogenic lines under artificial inoculation conditions, the PPLs with better resistance to seedling blast are PPL^Pigm/Pi1, PPL^Pigm/Pi54, PPL^Pigm/Pi33, PPL^Pi9/Pi33, PPL^Pi9/Pi54, PPL^Pi40/Pi54, PPL^Pi40/Pi33, PPL^Pi40/Pi1 and PPL^Pi9/Pi1, respectively, and the PPLs with outstanding performance in panicle blast are PPL^Pigm/Pi1, PPL^Pigm/Pi54, PPL^Pigm/Pi33, PPL^Pi40/Pi33, PL^Pi40/Pi54, PPL^Pi40/Pi1 and PPL^Pizt/Pi33, respectively. Different resistance gene combinations produced different effects after pyramiding. High complementary effect and which could be fully expressed is the key factor for the improvement of the resistance level of seedling blast and panicle blast of the PPLs. In addition, PPL^Pigm/Pi1, PPL^Pigm/Pi54 and PPL^Pigm/Pi33 displayed broad-spectrum resistance in artificial inoculation at seedling and heading stage, and showed stable broad-spectrum resistance under different disease nurseries. Besides, agronomic traits evaluation also showed PPLs with these three gene combinations were at par to the recurrent parent. Therefore, Pigm/Pi1, Pigm/Pi54 and Pigm/Pi33 are broad-spectrum resistance gene combination patterns suitable for japonica rice resistance breeding in lower region of the Yangtze River, China. 【Conclusion】The combination pattern of resistance genes affects the resistance level of the PPLs, and high complementary effect and which could be fully expressed is the key factor for the improvement of the resistance level of the PPLs in japonica background. In addition, the development of PPLs and component factors analysis in this study provides valuable theoretical support and innovative germplasm resources for the precise breeding broad-spectrum japonica varieties in lower region of the Yangtze River, China.