Nature Biotechnol. 33, 301–305 (2015)

The brown planthopper (BPH) is a major pest for rice production, causing up to 60% loss of yield in affected crops. Multiple biotypes and continuous evolution of BPH rapidly circumvent conventional methods of pest control. Instead, Yuqiang Liu, at the Nanjing Agricultural University, and colleagues have employed genes within a previously reported resistance locus, Bph3, to induce a broad-spectrum and an enduring defence against BPH.

Rice varieties exhibiting insect resistance due to the Bph3 locus have been used for more than 30 years. Liu et al. used populations derived from a cross between the resistant rice variety Rathu Heenati and the susceptible variety 02428 to map the Bph3 locus to a 79 kb region on chromosome 4, where four genes (OsLecRK14) encoding lectin receptor kinases were found. BPH-resistant lines had an identical sequence for OsLecRK13 but different sequences for OsLecRK4, indicating that the three-gene cluster (OsLecRK13) without OsLecRK4 represents Bph3. Indeed, BPH infestation dramatically induced the expression of OsLecRK1 and OsLecRK3 in resistant plants but not in their susceptible cousins, suggesting Bph3 increases the resistance by enhancing the inducible expression of lectin receptor kinases. This hypothesis was verified in transgenic rice lines over- or under-expressing the three OsLecRK genes.

Introducing Bph3 into a susceptible japonica variety, Ningjing 3, through marker-assisted selection significantly enhanced the resistance to BPH and white back planthopper. The gene cluster thus provides a valuable tool for breeding rice with broad-spectrum and durable insect resistance.