Bph27

Background

The brown planthopper (Nilaparvata lugens Stål; BPH) is one of the most hazardous rice pests in the world. Growing resistant varieties is the most active way to deal with this insect, and wild rice species are a valuable source of resistance genes for developing resistant cultivars. BPH27 derived from an accession of Guangxi wild rice, Oryza rufipogon Griff. (Accession no. 2183, hereafter named GX2183), was primarily mapped to a 17-cM region on the long arm of the chromosome four. Furthermore, fine mapping of BPH27 was conducted using two BC1F2 populations derived from introgression lines of GX2183. Insect resistance was assessed in the BC1F2 populations with 6,010 individual off springs, and 346 resistance extremes were obtained and employed for fine mapping of BPH27. High-resolution linkage analysis discover the BPH27 locus to an 86.3-kb region in Nipponbare.

Damage caused by brown planthopper

Mapping

Possible nature of BPH27

It is now known that the responses of rice to BPH feeding are most possibly similar to pathogen-defense responses (Wang et al. 2008; Du et al. 2009). For example, Bph14 is a member of the coiled-coil, nucleotide-binding, and leucinerich repeat (CC-NB-LRR) disease resistance gene family and provides resistance to BPH in a mechanism fundamentally similar to defense mechanisms against pathogens by activating an SA-dependent pathway (Du et al. 2009). The chromosome region containing BPH27 is rich in genes involved in disease response. Three predicted genes, LOC_Os04g31924, LOC_Os04g32000 and ORF12 of 93-11, are likely involved in response to disease and thus are considered the primary candidates of the BPH27 gene.

Potential use of BPH-resistance genes for rice improvement

Compared with dominant resistance genes to BPH, little progress has been made in recessive resistance genes. Fine mapping of BPH27 on chromosome 4, therefore, provides valuable information for understanding the molecular mechanisms underlying the recessive gene-mediated resistance. Candidate genes in the fine-mapped region by sequencing parental lines and transforming susceptible parent with cloned BPH27 candidate genes still need to be vindicated. Moreover, a number of simple molecular markers will be exploited to support in the development of rice cultivars that are resistant to multiple BPH biotypes.

References

1. D. Huang • Y. Qiu • Y. Zhang • F. Huang •J. Meng • S. Wei • R. Li • B. Chen Fine mapping and characterization of BPH27, a brown planthopper resistance gene from wild rice. Theor Appl Genet (2013) 126:219–229

2. Wang YY, Wang XL, Yuan HY, Chen RZ, Zhu LL, He RF, He GC (2008) Responses of two contrasting genotypes of rice to brown planthopper. Mol Plant Microbe Interact 21:122–132

3. Du B, Zhang WL, Liu BF, Hu J, Wei Z, Shi ZY, He RF, Zhu LL, Chen RZ, Han B, He GC (2009) Identification and characterization of Bph14, a gene conferring resistance to brown planthopper in rice. Proc Natl Acad Sci USA 106(52):22163–22168