南方水稻黑条矮缩病抗性的遗传分析及主效QTL的精细定位

Genetic Analysis and Fine Mapping of a Major QTL for the Resistance to Southern Rice Black-Streaked Dwarf Disease

【目的】近年来由白背飞虱传播的南方水稻黑条矮缩病给水稻生产造成了巨大损失,开展该病的抗性遗传分析和基因精细定位,将为抗性育种提供材料和理论依据。【方法】分析了抗性材料D4对南方水稻黑条矮缩病的抗性特征,并通过广恢998/D4F2群体分析该病抗性的遗传规律,利用QTL-seq技术联合遗传连锁分析定位主效抗性QTL。【结果】D4对南方水稻黑条矮缩病的抗性表现为抗病毒性而非抗虫性,且受主效基因和微效基因共同控制。QTL-seq和连锁分析将南方水稻黑条矮缩病主效抗性QTL定位于第9染色体上,命名为qSRBSDV9。利用代换作图法进一步将qSRBSDV9定位在102.3kb的区间内,该区间包含21个预测基因,其中9个基因与赤霉素信号传导相关。【结论】揭示了D4对南方水稻黑条矮缩病的抗性特征及遗传规律,精细定位了南方水稻黑条矮缩病主效抗性QTL qSRBSDV9。这为该QTL的图位克隆及育种利用奠定了基础。

【Objective】Southern rice black-streaked dwarf virus(SRBSDV), which is transmitted by white-backed planthopper (Sogatella furcifera Horváth, WBPH), has caused severe yield loss in epidemic years in rice production. We analyzed the resistance mechanism of SRBSDV and identified the related gene locus by fine gene mapping to lay a scientific base for effective prevention and control of SRBSDV.【Method】The resistance of rice material D4 against white-backed planthoppers were analyzed, and the genetic basis for the resistance to SRBSDV was analyzed by using F2 population of Guanghui 998×D4. The major QTL for resistance to SRBSDV was identified using QTL-seq, and further verified by genetic linkage analysis.【Result】D4 was resistant to SRBSDV but not to WBPH. Genetic analysis showed that the resistance of D4 was controlled by major gene and minor genes. QTL-seq and linkage analysis revealed that the major QTL for resistance to SRBSDV in rice was located within the 1.40 M region on chromosome 9, which was termed as qSRBSDV9. Then qSRBSDV9 was fine mapped on chromosome 9 with a 102.3 kb physical distance by substitution mapping. This region contained 21 predicted genes, nine of which were related to gibberellin signaling.【Conclusion】 The results reveals the characteristics and inheritance of resistance to SRBSDV in D4. The fine mapping of qSRBSDV9 lays a base for map-based cloning and utilization.