Mapping and pyramiding of two major genes for resistance to the brown planthopper (Nilaparvata lugens [Stål]) in the rice cultivar ADR52

Abstract

The brown planthopper (BPH), Nilaparvata lugens (Stål), is one of the most serious and destructive pests of rice, and can be found throughout the rice-growing areas of Asia. To date, more than 24 major BPH-resistance genes have been reported in several Oryza sativa ssp. indica cultivars and wild relatives. Here, we report the genetic basis of the high level of BPH resistance derived from an Indian rice cultivar, ADR52, which was previously identified as resistant to the whitebacked planthopper (Sogatella furcifera [Horváth]). An F(2) population derived from a cross between ADR52 and a susceptible cultivar, Taichung 65 (T65), was used for quantitative trait locus (QTL) analysis. Antibiosis testing showed that multiple loci controlled the high level of BPH resistance in this F(2) population. Further linkage analysis using backcross populations resulted in the identification of BPH-resistance (antibiosis) gene loci from ADR52. BPH25 co-segregated with marker S00310 on the distal end of the short arm of chromosome 6, and BPH26 co-segregated with marker RM5479 on the long arm of chromosome 12. To characterize the virulence of the most recently migrated BPH strain in Japan, preliminary near-isogenic lines (pre-NILs) and a preliminary pyramided line (pre-PYL) carrying BPH25 and BPH26 were evaluated. Although both pre-NILs were susceptible to the virulent BPH strain, the pre-PYL exhibited a high level of resistance. The pyramiding of resistance genes is therefore likely to be effective for increasing the durability of resistance against the new virulent BPH strain in Japan.

Fig. 1

Frequency distribution of nymph mortality of brown planthopper (Chikugo-89 strain) in the F₂ population derived from T65 × ADR52. The bars indicate standard deviations

Fig. 2

Location of detected QTLs, those confer resistance to the brown planthopper. Three QTLs, qBPH5, qBPH6, and qBPH12, were located on the linkage maps of rice chromosomes 5, 6, and 12, respectively. The genome-wide linkage map was constructed by 161 SSR markers using an F₂ population derived from T65 × ADR52. Critical threshold value of LOD score indicated by horizontal lines was equivalent to LOD = 2.9 at an experiment-wise significance level of 0.05

Fig. 3

Frequency distributions of adult mortality of brown planthopper (Chikugo-89 strain) in the BC₃F₂ 1 population (a) segregated for qBPH6 (SSR marker S00310 on chromosome 6) and in the BC₃F₂ 2 population (b) segregated for qBPH12 (RM5479 on chromosome 12) respectively, derived from T65 × ADR52

Fig. 4

Linkage maps indicating the positions of (a) BPH25 and (b) BPH26, brown planthopper (BPH)-resistance genes on rice chromosomes 6 and 12, respectively. The framework maps at the left of the figures are quoted from Harushima et al. (1998)

Fig. 5

a Adult mortality (%) of brown planthopper and b the proportion of BPH females with a swollen abdomen (%) 5 DAI on the pre-NILs and the pre-PYL of rice carrying BPH-resistance genes. The scores for Chikugo-89 strain were obtained from Myint et al. (2009a). The scores for Japan-KG-06 strain were obtained in the present study. Values represent mean and standard deviations (n = 7). Mean labeled with the same letters do not differ significantly in a and b, respectively (P < 0.01, Tukey–Kramer test)

Fig. 6

Comparison between the chromosomal locations of (a) BPH25 (present study) and (b) Bph3 (Jairin et al. 2007b) and bph4 (Jairin et al. 2010) on the short arm of chromosome 6; and the chromosomal locations of (c) BPH26 (present study) and (d) Bph18(t) (Jena et al. 2006) and Bph1 (Cha et al. 2008) on the long arm of chromosome 12. The black arrows indicate the locations of the genes. The crosshatched bar indicates the location of the peak LOD in the QTL analysis