Genetic Analysis and Gene Mapping of Whitebacked Planthopper Resistance Genes from Rice Varieties
Genetic Analysis and Gene Mapping of Whitebacked Planthopper Resistance Genes from Rice Varieties
Baoxuan Nong1,2, Biqiu Wu3, Anlong Xu2, Wenai He2 and Yongfu Qiu2*
ABSTRACT
The whitebacked planthopper (WBPH), also named Sogatella furcifera (Horváth), has become a significant threat to rice production. Identification of WBPH-resistant germplasm and genes can promote the development of resistance varieties and effectively limit pest damage. In this study, fourteen varieties of rice were surveyed for insect resistance by assessing growth rates via seedbox screening, feeding activity via measurements of honeydew excretion, and insect development by counting the number of hatched nymphs. Two resistance varieties N22 and OB677 were crossed with susceptible line 9311 to develop mapping populations, which were applied to map the resistance genes/QTLs. In the results, rice variety PTB33 showed high resistance to both brown planthopper (BPH) and WBPH, varieties N22, RBPH327, and OB677 showed moderate resistance to WBPH. Host choice test and seedling survival rates further verified the WBPH resistance of PTB33, N22, and OB677. By using two F2 mapping populations, two WBPH resistance genes were detected in N22 and OB677. Wbph1 was mapped on chromosome 2 of N22 in a region that harbored the markers RM13650 and RM13478. Its largest logarithm of the odds (LOD) score was 3.94, which explained a 16.6% of the phenotypic variation. Wbph9 was mapped on chromosome 3 of OB677, where it was flanked by markers RM3513 and RM3525. It had a LOD score of 3.4, explaining a 17.2% of the phenotypic variation. Four varieties PTB33, N22, RBPH327, and OB677 showed resistance to WBPH, of which OB677 was a novel resistance germplasm; and a novel resistance gene Wbph9 was mapped on chromosome 3. In conclusion, four WBPH resistance varieties were detected and one novel resistance gene was mapped.
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