Identification of flanking SSR markers for a major rice gall midge resistance gene Gm1 and their validation

Abstract

Host-plant resistance is the preferred strategy for management of Asian rice gall midge (Orseolia oryzae), a serious pest in many rice-growing countries. The deployment of molecular markers linked to gall midge resistance genes in breeding programmes can accelerate the development of resistant cultivars. In the present study, we have tagged and mapped a dominant gall midge resistance gene, Gm1, from the Oryza sativa cv. W1263 on chromosome 9, using SSR markers. A progeny-tested F2 mapping population derived from the cross W1263/TN1 was used for analysis. To map the gene locus, initially a subset of the F2 mapping population consisting of 20 homozygous resistant and susceptible lines each was screened with 63 parental polymorphic SSR markers. The SSR markers RM316, RM444 and RM219, located on chromosome 9, are linked to Gm1 at genetic distances of 8.0, 4.9 and 5.9 cM, respectively, and flank the gene locus. Further, gene/marker order was also determined. The utility of the co-segregating SSR markers was tested in a backcross population derived from the cross Swarna/W1263//Swarna, and allelic profiles of these markers were analysed in a set of donor rice genotypes possessing Gm1 and in a few gall midge-susceptible, elite rice varieties.

A new rice gall midge resistance gene in the breeding line CR57-MR1523, mapping with flanking markers and development of NILs

“…Flanking markers are of great value in introgression of the target gene through MAS. Based on product rule of probability, flanking SSR markers help in accurate prediction of the gene with less than 1% error (Biradar et al 2004). …”

“…So far, seven of the gall midge resistance genes have been tagged and mapped using molecular markers (Jain et al 2004). Tightly linked (preferable\2 cM) and/or flanking co-dominant markers (\5 cM on either side of gene locus) help to effectively pyramid genes (Biradar et al 2004). Availability of abundant and versatile microsatellite or Simple Sequence Repeat (SSR) markers in the rice genome (Mc Couch et al 2002) and information on their physical position in the rice genome provide an opportunity to map any gene of interest.…”

A novel mechanism of gall midge resistance in the rice variety Kavya revealed by microarray analysis

“…However, the molecular basis of rice gall midge interactions is still to be deciphered. The rice variety Kavya, carrying Gm1gene, is resistant to four out of seven gall midge biotypes found in India and shows HR− type of resistance (Biradar et al 2004). Development and cultivation of the gall midge-resistant rice varieties has been the main approach to mitigate the pest inflicted production loss.…”

Flanking Microsatellite Markers for Breeding Varieties Against Asian Rice Gall Midge

“…Microsatellite markers, RM219, and RM444 were identified to be linked to gall midge resistance gene, Gm1 in rice cv. W1263 (Biradar et al 2004). RAPD markers, E20 570 and RFLP markers, R1813 and S1633B were identified linked to the gall midge resistance gene, Gm4 in rice cv.…”