Genetic Analysis and Molecular Mapping of QTL for Rice Black-Streaked Dwarf Disease Resistance in Rice
|School||Nanjing Agricultural College|
|Keywords||Rice black-streaked dwarf disease small brown planthopper resistance genetic linkage map QTL mapping|
Rice black-streaked dwarf disease, lastingly transmitted by small brown planthopper (Laodelphax striatellus Fallen, SBPH) is one of the important pernicious viruse diseases, which is caused by rice black-streaked dwarf virus (RBSDV). The disease was firstly reported in Japan, and firstly occurred in 1963 in Yuyao County, Zhejiang Province. It became serious in 1963-1967 and reduced quickly after 1967, but the incidence trend increased year by year in 1980s, which seriously endangered the safety of rice. According to the statastics of Plant Protection Station of Jiangsu, the area of disease increased rapidly from 2.05x10hm in 2007 to 2.67x10hm in 2008, and increased continuously to 3.33x10hm in 2009. For the persistency and instantaneity of planthopper transmission, pest control treatment is facing great difficulties. Therefore, breeding and utilization of resistant varieties is the one of the most excellent and long-lasting methods. Breeding new RBSDV-resistant varieties, including mining rice resources, locating resistance genes and molecular markers assisted selection, is the important control strategy of rice black-streaked dwarf disease.This study analyzed the RBSDV/SBPH resistance features of Huai 5 and Tetep, builded a genetic linkage map by the F2 population of Huai 5/Tetep, and also detected the quantitative trait loci of rice black-streaked dwarf disease resistance by analyzing the resistance features of F families through the artificial inoculation. The main results are as follows:In order to screen out the anti-rice variety of rice black-streaked dwarf, indoor artificial inoculation, non-addicted test and non-resistant test had experimented. The resistance analyses of rice varieties to SBPH showed that Huai 5 and Tetep had non-addicted and non-resistant features. The resistance analyses of rice varieties to RBSDV by indoor artificial inoculation indicated that Huai 5 was susceptible and Tetep was resistant. The results provided the basis for selection of breeding resistant resources to RBSDV.Polymorphism were detected between Huai 5 and Tetep by 663 SSR primers from http://www.gramene.org, in which there were 174 SSR primers showing polymorphisms and the ratio of polymorphisms was 26.24%. A molecular linkage map including 104 SSR markers was constructed using the F2 population(Huai 5/Tetep), and the length of the map was 2125.1 cM with an average interval size 21.1 cM. All sites were uniformly distributed on 12 chromosomes.The map has a good foundation for resistance QTL mapping,cloning and molecular marker-assisted breeding of RBSDV..F2:3 families were growed in summer in 2010, and were examined the resistance of RBSDV. The incidence rate was continuously distributed between 1-100%, indicated that the trait was quantitative traits. QTL controlling RBSDV resistance was analyzed by software of Windows QTL Cartographer 2.5. Four major RBSDV resistance QTLs, one mapped to chromosome 3, two mapped to chromosome 5 and one to chromosome 11, were identified, and two of which were from Tetep. One locus designated as qRBSDV-5-2 has the highest PVE (phenotypic variance efficiency) of 23.75%. Our study could provide convenience and theory reference for the breed selection of appropriate resistance by marker assisted selection (MAS), the separation of RBSDV resistant gene by map-based cloning, and the elucidating of the functions of RBSDV resistant genes.