Identification and fine mapping of Bph33 , a new brown planthopper resistance gene in rice ( Oryza sativa L.)

摘要

Background Host-plant resistance is the most desirable and economic way to overcome BPH damage to rice. As single-gene resistance is easily lost due to the evolution of new BPH biotypes, it is urgent to explore and identify new BPH resistance genes. Results In this study, using Fsub2:3/sub populations and near-isogenic lines (NILs) derived from crosses between two BPH-resistant Sri Lankan rice cultivars (KOLAYAL and POLIYAL) and a BPH-susceptible cultivar 9311, a new resistance gene Bph33 was fine mapped to a 60-kb region ranging 0.91–0.97?Mb on the short arm of chromosome 4 (4S), which was at least 4?Mb distant from those genes/QTLs ( Bph12 , Bph15 , Bph3 , Bph20 , QBph4 and QBph4.2 ) reported before. Seven genes were predicted in this region. Based on sequence and expression analyses, a Leucine Rich Repeat (LRR) family gene (LOC_Os04g02520) was identified as the most possible candidate of Bph33 . The gene exhibited continuous and stable resistance from seedling stage to tillering stage, showing both antixenosis and antibiosis effects on BPH. Conclusion The results of this study will facilitate map-based cloning and marker-assisted selection of the gene.