Genetic Analysis On Rice Blast Sterile Line Lineage And Homologous Sequences Of Resistance Genes

Male sterial line is one of the most important parents of hybrid rice. Rice sterial line with durable blast resistance that can be applied on the production in vast area is few now. Selecting the blast-resistance sterial line with excellent integrated characters is one of the most important tasks. This research used the blast-resistance sterial line lineage as researching materials which were raised by the institution of rice research in the college of Fujian agricultural science for seventeen years, including Gunong13, Tiangu (1991 raised), Fuyi (1995 raised), Gufeng (2001 raised), Quanfeng (2004 raised) .At the genetic background of five near-isogeneic lines and one susceptible comparison LTH using CO39 as the parents, we manually matched the genetic materials of near-isogeneic lines and susceptible comparisons including three generation of P,F₁,F₂,with Gunong13, Tiangu, Fuyi, Gufeng, Quanfeng. We studied the genetic rules of the blast-resistance sterial line lineage and the allelic relationship by means of classical genetic methods with two blast-resistance strains, 97-102-16 and 98022B, for spraying inoculation and fastness identification. According the known conserved domain of the amino acid in the NBS-LRR structure genes, we can design the degenerate primer and clone, sequence and cluster the resistance gene analogs (RGAs) by polymerase chain reaction (PCR) in order to study the passing rules of resistance genes and analyze the comparability of blast phenotype and RGAs, offering the scientific reference for utility and clone of rice blast genes. The results were showed as follows:1,The genetic research on blast-resistance sterial line lineage showed that Gunong13, Tiangu, Fuyi , Gufeng , Quanfeng expressed high resistance to the strains of 97-102-16 and 98022B. Five CO39 near-isogeneic lines showed resistance reaction to 97-102-16．But they showed difference to 98022B. Only the C104OKT near-isogeneic line showed high susceptible to 98022B, the other four showed resistant reaction. Lijianxintuanheigu (LTH) and CO39 were susceptible to 97-102-16 and 98022B. If spray Inoculating the 97-102-16, the resistance of Gunong13 and Quanfeng were controlled by one dominant gene. And the resistance of Fuyi and Gufeng were controlled by two dominant genes. And the resistance of TianguB was controlled by three dominant genes. And one dominant gene of Tiangu is allelic to gene Pi-3, the others are independent hereditarily to gene Pi-1, Pi-2,Pi-3,Pi-4aå’ŒPi-4b. If spray Inoculating the 98022B, the resistance of Gunong13,Tiangu, Fuyi ,Gufeng ,Quanfeng were controlled by one dominant gene. And the dominate gene of Gugeng was linked hereditarily to gene Pi-1 and Pi-4b, the others were independent hereditarily to gene Pi-1,Pi-2,Pi-3,Pi-4 and Pi-4b.2,The cloning and analysis of the homologous sequence of resistant genes of the rice sterial line lineage showed that 14 masculine clones have been obtained from 7 rice sterial line lineage (named C1-5,C-6,C2-2,C2-6,C3-6,C3-7,C5-4,C5-6,C10-2,C10-4,C14-2,C14-6,C17-1,C17-4) . And there were only 11 NBS-LRR resistant genes which had particular conservative domain, Kinaseâ… ,Kinaseâ…¡,Kinaseâ…¢and transmembrance domain. In the amino acid segments of the NBS-LRR type, the maximal homologous quality was 98．3%, the minimum was 29．7%. These 11 NBS-LRR type sequences were highly homologic to resistant gene Xal (AB002266) , which had 42%-45% identical amino acids and 59%-64% similar amino acids by the BLAST in NCBI. These NBS-LRR type resistant sequences have been separated into three types, which were named G1, G2, G3 by clustering analysis. And it showed that the G3 type genes of Gunong13 had been passed to generation of Gufeng and Quangfeng through the generation Tiangu and Fuyi.To further utilize and clone the rice sterial line lineage resistance genes, the technical channel will be discussed more in the text.