The whitebacked planthopper (WBPH), Sogatella furcifera Horváth, is a serious rice pest in Asia. It damages the plants by sucking sap from the phloem and transmitting viruses, which lead to reductions in plant height, number of productive tillers, filled grains, and yield. Ovicidal resistance is a natural rice defense mechanism against WBPH and is characterized by the formation of watery lesions (WLs) and increased egg mortality (EM) at the WBPH oviposition sites. The exploitation of rice resistance has generally been considered one of the most economical and environmentally friendly approaches for the management of WBPHs.

Based on the Chinese japonica rice variety Chunjiang 06 (CJ06), which showed the strongest ovicidal response to WBPHs and exhibited sucking-inhibitory resistance to the WBPH, the researchers from China National Rice Research Institute (CNRRI) of Chinese Academy of Agricultural Sciences (CAAS) and Institute of Genetics and Developmental Biology, Chinese Academy of Sciences created doubled haploid rice lines derived from a WBPH resistant cultivar (CJ06) and a WBPH-susceptible cultivar (TN1) for further research of rice resistance to WBPHs. Through genetic analysis and molecular mapping, 19 quantitative trait loci (QTLs) associated with WLs and EM were identified on eight chromosomes and a major QTL among them for WL as qWL6 was determined. Based on chromosome segment substitution lines and a residual heterozygous population, a high-resolution linkage analysis further defined the qWL6 locus to a 122-kb region on chromosome 6, which was annotated to encode 20 candidate genes. By conducting an Affymetrix microarray analysis to determine the transcript abundance in the CJ06 and TN1 plants, four genes in the 122-kb region of the qWL6 locus were differentially regulated between CJ06 and TN1 in response to the WBPH infestation, suggesting they may be candidate resistance genes. The research results will facilitate isolating this important resistance gene and its use in breeding WBPH resistance rice.

This work was supported by grants from the Ministry of Agriculture of China for transgenic research (No.2013ZX08009003-001), the National Natural Science Foundation of China (31221004, 31171531) and the State Key Basic Research Program (2013CBA01403). The research result was published on BMC Plant Biology (2014) doi:10.1186/1471-2229-14-145

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