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nature biotechnology advance online publication l e t t e r sThe brown planthopper (BPH) is the most destructive pest of rice (Oryza sativa) and a substantial threat to rice production, causing losses of billions of dollars annually 1,2 . Breeding of resistant cultivars is currently hampered by the rapid breakdown of BPH resistance 2 . Thus, there is an urgent need to identify more effective BPH-resistance genes. Here, we report molecular cloning and characterization of Bph3, a locus in rice identified more than 30 years ago that confers resistance to BPH. We show that Bph3 is a cluster of three genes encoding plasma membrane-localized lectin receptor kinases (OsLecRK1-OsLecRK3). Introgression of Bph3 into susceptible rice varieties by transgenic or marker-assisted selection strategies significantly enhanced resistance to both the BPH and the white back planthopper. Our results suggest that these lectin receptor kinase genes function together to confer broad-spectrum and durable insect resistance and provide a resource for molecular breeding of insect-resistant rice cultivars.BPH (Nilaparvata lugens Stål, Hemiptera, Delphacidae) is a monophagous, phloem-sucking herbivore. It sucks the sap from the rice phloem using its stylet, and causes direct damage to rice plants. BPH can also cause indirect damage to rice plants through the transmission of viruses including the rice ragged stunt virus and grassy stunt virus 2 . Repeated overapplication of pesticides for BPH management has heavily polluted the environment 3 . Breeding of resistant cultivars is the most cost-effective and environmentally responsible strategy for BPH management but developing insect resistant cultivars by traditional breeding approaches is extremely difficult and time consuming owing to a paucity of knowledge about BPH resistance genes and germplasm.To date, 28 BPH resistance loci have been identified from cultivated and wild species of Oryza 2,4,5 . Only two of these resistance genes, Bph14 and Bph26 have been cloned to date 6,7 . In addition, BPH resistance of IR26 and IR36, two widely cultivated rice varieties that harbor the BPH resistance loci Bph1 and bph2, respectively, was quickly broken down in just a few years owing to the rapid adaptation of the BPH 8 . Thus, there is still an urgent need to identify new types of resistance genes and germplasm for developing efficient approaches to breed broad-spectrum and durable BPH-resistant rice cultivars. Notably, the Bph3 locus, originally identified in the Sri Lankan indica cultivar Rathu Heenati 9 , displayed resistance to four BPH biotypes (BPH biotypes refer to specific populations of BPH classified according to their virulence on different BPH resistance genes) 2,10 . Furthermore, rice varieties harboring Bph3 deployed more than 30 years ago in the Philippines are still resistant to BPH 8 . However, the molecular basis of this broad-spectrum and durable resistance of Bph3 against BPH remains unknown.We observed that Bph3-containing Rathu Heenati infested with BPH of mixed biotypes (biotype ...

BackgroundBrown planthopper (BPH) is the most destructive insect in rice production. Breeding of resistant cultivars is the most cost-effective and environment-friendly strategy for BPH management; however, resistant cultivars are currently hampered by the rapid breakdown of BPH resistance. Thus, there is an urgent need to use more effective BPH resistance genes or pyramiding different resistance genes to develop more durable resistant rice cultivars.ResultsHere a dominant BPH resistance gene Bph27(t) were introgressed into a susceptible commercial japonica variety Ningjing3 (NJ3) and indica variety 93-11 using marker-assisted selection (MAS), respectively. Further, Bph27(t) and a durable BPH resistance gene Bph3 was pyramided by intercrossing single-gene introgressed lines through MAS. The introgression of BPH resistance genes significantly improved the BPH resistance and reduced the yield loss caused by BPH.ConclusionThe development of single and two genes pyramided lines in this study provides innovative resources for molecular breeding of durable BPH-resistant rice cultivars and BPH management through resistant cultivars.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-016-0096-3) contains supplementary material, which is available to authorized users.

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Brassinosteroids play a negative role in rice defense against infestation by the brown planthopper through contrasting effects on the salicylic acid and jasmonic acid pathways.