Qtl Mapping And Candidate Genes Screening Of Drought Resistance On Chromosome4in Rice

Drought stress is one of the most serious disasters, influencing on crop production in China seriously. Increasingly food demand and the water shortage situation make it clear that the study of drought is critical and urgent. Rice is the main food crop in China, high water consumption and also one of the most easily affected by drought.Therefore, the study and breeding of water-saving and drought-resistant rice contributes to development of modern water-saving agriculture, ensure food safety. QTL mapping of drought resistance traits and cloning research is an important means of rice drought resistance current research, which is also a hot research topic. To report the positioning of the concentrated on physiological character, root traits and yield and yield related traits, get a lot of QTL. Because of the complexity of drought resistant phenotype identification and difficulty in the large group size detection, coupled with drought resistance is highly affected by the environment, have been reported follow-up of drought resistance QTL fine positioning progress has been slow.As early as2004our lab built a RIL population (F9) derived from the parents of ZS97B and IRAT109, together wih the phenotype under drought stress, mapped several QTLs of PL, PN, PH, SNP, GY, BY multiple production related properties on the range of RM273-RM255on Chr4, gathering in the form of gene cluster. After that, with the recurrent parent ZS97B consecutive backcross and selfing, contributing to an advanced backcross population (BC4F4), also mapped QTLs of PL, PN, SNP on the target region on Chr4. The mapping population and results above still have shortcomings:measured by the tag in the target segment restructuring exchange, there are still large linkage segment, go against further fine mapping; localization of QTL range is bigger, difficult to select candidate genes for functional verification, and localization to the location is not coincidence, still need to test and verify. Is a continuous experiment, this study aims to solving these problems by expanding the mapping population, to obtain the ideal individuals of which the chromesome exchange on different sites in the target region. Build new mapping population and fine map in RM273-RM255area. Main results of the present are as following:1. Construct new substitute lines for mapping. Screen Chr4target region with polymorphism markers. With the sequencing data of ZS97B and IRAT109, I designed115pairs of SSR or InDel markers, combined with the published molecular markers, at last selected20pairs can be screened out in agarose gel electrophoresis detection,32of PAGE to detect the polymorphism. By marking results, choose the target segment import IRAT109chromosome fragment strain C98return with ZS97B selfing get7000familities of F2(BC5F2) groups. The use of20for genotyping the F2group, screening to527strains of materials in different sites Chr4target segment exchange new restructuring, ultimately chose115plants of Chr4target segment substitute lines, used in the study of drought resistance QTL localization.2. The phenotype under drought stress. The control and stress group were tested respectively which were identified of production and related traits. Identifying the island in2013severe Under investigation by the various characters in addition to plant height, heading date, seed fersility, spikelet number per panicle, relative water content, primary branch, the yield under normal water stage and Panicle length,the solid grain number, heading date, hundred grain weight under drought stress, were significantly different between the parents, two kinds of processing between parents under the heading stage difference were not significant. All properties of the population showed significant differences between water and drought treatment. Adopt the method of path analysis will yield related traits on yield effect size and function way were analyzed. Under normal water condition the direct path coefficient of each related traits and yield size order: DGN> HGW> FBN> BY> TN> PH> SNP> PL> PN> SF> SBN, and because of the influence of water stress, the direct path coefficient of yield components order change:DGN>HGW>PH>FBN>BY>PL>SF>SNP>TN>PN>SBN.3. QTL mapping of the drought resistance on the target region on Chr4. Genotype data according to the group and F3family materials (BC5F3) data of drought resistant phenotype in LOD>2.5under normal water level detected panicle length, spikelet number per panicle, secondary branch number, wrapround spikelet rate related QTL. Under drought stress were detected the tiller number and effective panicles, empty grain number and grain number and panicle length, plant height stress index related QTL, positioning results show that the localization of QTL focused on M13-M20-M21-RM241hotspots, the positioning results accord with the results of2009location, are shown together with drought resistance related QTL hot area. We find273genes which have been annotationed. In the network of rice drought resistance genes we get25hub genes related to drought resistance, in which LOC_Os04g44670codes AP2domain transcription factor structure, the family protein has been proven in drought adversity; LOC_Os04g43420codes PTAC5protein, there are reports that the proteins may be associated with heat resistant reaction; LOC_Os04g45210peroxidase can promote body split proliferation, may be related to drought resistance; LOC_Os04g46450encodes zinc finger protein, there are reports that may be related to improve plant adversity resistance.