| Rice bacterial blight is a major bacterial disease in rice production. The best way to prevent rice bacterial blight is to develop resistant varieties using resistance genes. But the resistance would be lost after planting for a certain time. To use the resistance genes, the mechanisms of rice bacterial blight resistance and the potential of the resistance genes should be clear. The interaction between plant and the pathogen is a complex process, which involves huge gene interaction and many pathways. As the rice genome sequencing project has been finished, the technique of gene chip has become mature and the development of in rice functional genomics, to analyze the entire gene expression in rice under Xanthomonas oryzae stress using gene chip has become available.Xa23 is one of resistant genes that has broad-spectrum and wide application. To analysis the resistance mechanism of Xa23 and provide the information to clone Xa23. We transfer Xa23 to shuhui527, a restorer line. And the near isogentc lines (NILs) carring the Xa23 was developed using the backcrossing, selfing and molecular marker-assisted selection (MAS) technique. The entire gene expression in two NILs was analyzed using microarray chips containing 57381probes, to compare the differences under Xanthomonas oryzae stress at 12 h after inoculation. The result is as follows: 1. 522 SSR primers distributing on 12 chromosomes were used to detect polymorphism between shuhui527 and BR1, and 87 primers were found polymorphic. The 87 polymorphic markers were used to examined the candidate lines, and two lines (L16,L17) showed similar genetic background except for the Xa23 locus. The agronomic traits between L16 and L17 had no significant differences, therefore the L16 and L17 were considered as good NILs.2. 911 genes were found differentially expressed between resistant line L16 and the susceptible line L17. There are 753 genes were up-regulated and 158 genes were down-regulated of the 911 genes. The up-regulated genes were significantly more than the down-regulated genes. The Gene ontology results showed that the differentially expressed genes mainly involved the cell part, the cell, the physiological process, the cell process and metabolism and so on. The KEGG pathway analysis showed that differentially expressed genes were mainly for the ubiquinone biosynthesis, ribosome, and oxidative phosphorylation, biosynthesis of steroids, valine, leucine and isoleucine degradation, benzoate degradation via CoA ligation, metabolism of xenobiotics by cytochrome P450, and phosphatidylinositol signaling system and so on.3. In the 753 up-regulated genes, it was predicted that 653 genes had function, 14 genes had unknown function, 217 genes were predicted as hypothetical protein, no annotation were available for 100 genes. In the 158 down-regulated genes, it was predicted that 139 genes had function, 3 genes had unknown function, 30 genes were predicted as hypothetical protein, no annotation were available for 19 genes. Among the up-regulated genes, two genes (Os11g0588600,Os11g0640300) locating on chromosome 11, and belonged to disease resistance protein family; 7 genes encoded Cytochrome P450 family protein; 16 genes encoded Protein kinase; 3 genes encoded NADH ubiquinone oxidoreductase; 2 genes encoded Myb DNA-binding domain containing protein; 3 genes encoded Thaumatin pathogenesis-related family protein. Among the down-regulated genes, 2 genes belonged to the Cytochrome P450 family protein; 3 genes encoded the Protein kinase. These results provided information for explaining the resistance mechanisms of rice.The Xa23 was transferred to the restorer line yihui1577 by backcrossing, selfing and randomly selection. The foreground selection and background selection for BC1F7 and BC2F6 were conducted by MAS and their main agronomic traits were investigated. The recurrent proportion of the parental genome was detected for BC1F7 and BC2F6 lines, and their agronomic traits were also examined to check between the backcrossed lines and the recurrent parent. Some outstanding lines were test crossed with sterile line TianfengA to examine the comparability, hetorosis. The results are as follows: 1. 522 SSR primers distributing on 12 chromosomes were used to detect polymorphism between yihui1577 and BR1, and 105 primers were found polymorphic. The polymorphic ratio was 20.11%. The genetic background of 13 BC1F7 lines and 11 BC2F6 lines were examined using the 105 polymorphic primers. It showed that the recurrent proportion of the parental genome of the 13 BC1F7 lines ranged from 60.10% to 74.29%, the recurrent proportion of the parental genome of the 11 BC2F6 lines ranged from 81.43% to 91.43%. The recurrent proportion of the parental genome of BC1F7 lines and BC2F6 lines were close to the theory proportion of recurrent parent genome.2. The panicle length and flag leaf length of the 13 BC1F7 lines were not significantly different. Most lines had similar productive panicle number and flag leaf width as yihui1577. The productive panicle number and flag leaf length of the 11 BC2F6 lines had no significant difference, while the panicle length and seed setting rate of most of the BC2F6 lines were similar.3. In the test cross variety of BC1F7, the productive panicle number, flag leaf length and flag leaf width of all lines had no significant differences; and panicle length, grain number per panicle and grain yield of most lines had no significant differences. But the seed setting rate and 1000-seed weight were significantly different, affecting by different donor parents. In the test cross variety of BC2F6, the productive panicles number of all lines had no significant difference; the panicle length, grain number per panicle, seed setting rate, grain yield, flag leaf length and flag leaf width of most lines had no significant differences. The 1000-grains weights of all the lines were higher than yihui1577, and all had significant differences except for LT81, LT83 and LT86.
|
PDF Full Text Request