High-resolution mapping of a new brown planthopper (BPH) resistance gene, Bph18(t), and marker-assisted selection for BPH resistance in rice (Oryza sativa L.)

Abstract

Brown planthopper (BPH) is a destructive insect pest of rice in Asia. Identification and the incorporation of new BPH resistance genes into modern rice cultivars are important breeding strategies to control the damage caused by new biotypes of BPH. In this study, a major resistance gene, Bph18(t), has been identified in an introgression line (IR65482-7-216-1-2) that has inherited the gene from the wild species Oryza australiensis. Genetic analysis revealed the dominant nature of the Bph18(t) gene and identified it as non-allelic to another gene, Bph10 that was earlier introgressed from O. australiensis. After linkage analysis using MapMaker followed by single-locus ANOVA on quantitatively expressed resistance levels of the progenies from an F2 mapping population identified with marker allele types, the Bph18(t) gene was initially located on the subterminal region of the long arm of chromosome 12 flanked by the SSR marker RM463 and the STS marker S15552. The corresponding physical region was identified in the Nipponbare genome pseudomolecule 3 through electronic chromosome landing (e-landing), in which 15 BAC clones covered 1.612 Mb. Eleven DNA markers tagging the BAC clones were used to construct a high-resolution genetic map of the target region. The Bph18(t) locus was further localized within a 0.843-Mb physical interval that includes three BAC clones between the markers R10289S and RM6869 by means of single-locus ANOVA of resistance levels of mapping population and marker-gene association analysis on 86 susceptible F2 progenies based on six time-point phenotyping. Using gene annotation information of TIGR, a putative resistance gene was identified in the BAC clone OSJNBa0028L05 and the sequence information was used to generate STS marker 7312.T4A. The marker allele of 1,078 bp completely co-segregated with the BPH resistance phenotype. STS marker 7312.T4A was validated using BC2F2 progenies derived from two temperate japonica backgrounds. Some 97 resistant BC2F2 individuals out of 433 screened completely co-segregated with the resistance-specific marker allele (1,078 bp) in either homozygous or heterozygous state. This further confirmed a major gene-controlled resistance to the BPH biotype of Korea. Identification of Bph18(t) enlarges the BPH resistance gene pool to help develop improved rice cultivars, and the PCR marker (7312.T4A) for the Bph18(t) gene should be readily applicable for marker-assisted selection (MAS).

Allelic diversity in an NLR geneBPH9enables rice to combat planthopper variation

“…On the basis of our results and knowledge currently available about BPH-resistance genes on chromosome 12L, we propose that allelotype BPH1/9-1 (including previously reported BPH1, BPH10, BPH18, and BPH21) evolved early in the wild progenitor of rice based on two lines of evidence. First, BPH10 and BPH18 were introgressed from the wild rice species O. australiensis (E genome) (29,42) and BPH21 from O. minuta (BC genome) (30), respectively. Second, the allelotype BPH1/9-1 (H20) was found to be the most widespread among the four resistant allelotypes in rice populations (SI Appendix, Table S2).…”

“…S14B; refs. [26][27][28][29][30]. Thus, our findings demonstrated that the eight genes in this cluster are multiple alleles of the same locus, and, to honor the priority in the literature, we designate this locus BPH1/9.…”

“…In addition to BPH9, seven BPH-resistance genes (BPH1, BPH2, BPH7, BPH10, BPH18, BPH21, and BPH26) have been reported on chromosome 12L (12,14,(26)(27)(28)(29)(30). Among them, BPH26 has been cloned, and BPH2 is identical to BPH26 (ref.…”

Application and utilization of marker assisted selection for biotic stress resistance in hybrid rice (Oryza sativaL.)

“…Previous results have been reported that brown planthopper is a destructive phloem sap sucking pest of rice which has negative effect both qualitative and quantitative (Jena et al 2006). In this study, we searched for hybrid lines having resistant genes for brown plant hopper, namely, Bph1, Bph18(t), and Wbph in 173 hybrid rice lines.…”

LOW ASSOCIATION OF Bph17 ALLELE IN LANDRACES AND IMPROVED VARIETIES OF RICE RESISTANT TO BROWN PLANTHOPPER

“…Sun et al (2005) and Jena et al (2006) revealed that RM8213 and RM5953 DNA markers are closely linked to Bph17 gene that controls the expression of resistance trait. These markers can be used as a tool of marker assisted selection (MAS) with marker alleles at 177 bp on RM8213 PCR products and 140 bp on RM5953 PCR products (Sun et al 2005;Jena et al 2006). DNA products of RM8213 follow the Mendelian inheritance pattern of 1:2:1 (susceptible: heterozygous segregation: resistant) (Pertiwi et al 2014;Carsono et al 2016).…”