Abstract
Wide variation in ultraviolet-B (UVB) resistance is observed among rice varieties. Rice qUVR-10, a quantitative trait locus (QTL) for UVB resistance on chromosome 10, was detected by backcross inbred lines derived from a cross between a japonica variety Nipponbare (UV-resistant) and an indica variety Kasalath (UV-sensitive). Plant with homozygous of Nipponbare allele at the qUVR-10 were resistant to UVB compared with that with Kasalath allele. High-resolution mapping using 1850 F2 plants enabled to delimit qUVR-10 to <27-kb genomic region. We identified a gene encoding the cyclobutyl pyrimidine dimer (CPD) photolyase in this region. We introduced genomic fragment containing CPD photolyase gene of Nipponbare to NIL(qUVR-10). Transgenic plant showed same level resistance as Nipponbare, indicating that the qUVR-10 encoded the photolyase. Comparison of qUVR-10 sequence between Nipponbare and Kasalath allele revealed one probable candidate for the functional nucleotide polymorphism. Furthermore, we could develop UV-hyperresistant rice plant by over-expression of photolyase gene.
