Construction of a genomic library from a brown planthopper-resistant rice line using a transformation-competent vector and identification of clones spanning the Qbp1 locus

Brown planthopper (BPH), Nilaparvata lugens Stal, is one of the most serious insect pests of rice (Orazy sativa L.). In the introgression line 135, two loci conferring BPH resistance have been mapped onto chromosomes 3 and 4; the locus between markers R1925 and G1318 on chromosome 3 was named Qhp1. In the recombinant inbred lines between resistant line B5 and Susceptible line Minghui63, Qbp1 displayed high resistance to BPH. To streamline map-based cloning of the BPH resistant genes, a genomic library from resistant line B5 was constructed using the binary vector pCLD04541. The library contained 36 864 clones with an average insert size of 60 kb, an adaptable size to transform rice, amounting to 5.1 times the haploid rice genome. Eleven clones were identified to make a contig covering the Qbp1 locus completely and to transform the sensitive parent to further narrow the target gene locus into a relatively small region by complementation test. Since several important genes other than BPH resistance have also been identified and mapped in B5, this library is a valuable resource to clone these mapped genes. (C) 2003 Elsevier Ireland Ltd. All rights reserved.