Identification Of Cucumber Resistant Downy Mildew Mutuality Gene By DDRT-PCR Method

Cucumber downy mildew is a main disease on cucumber dependency planting,research on cucumber resistant downy mildew gene has become to a hot work inresistant disease breeding field. This research use Dong Nong 129 which resistcucumber downy mildew as experimentation material, use DDRT-PCR methodresearch the cucumber leaf differential expressed gene after they were invaded bydowny mildew pathogeny bacterium. The aim is search for genes which interrelate tocucumber downy mildew resistant and assistant cucumber resistant disease breedingwork. We do a further work to analysis the gotten gene's space-time express,validated their expression speciality.Main research outcome include:(1) Identify 31 differential expressed genes by reverse Northern method to eliminatefalse positive genes, We got 3 positive differential expressed genes. They wereconnected to vector and transform to E.coli. For the move togetherelectrophoresis phenomenon, NO.50 differential expressed gene contain 2 genes.So we obtain 4 positive differential expressed clones that interrelate to cucumberdowny mildew resistant, they are 49-2, 50-5, 50-7 and 52-14. By he way ofonline blast, 50-7 is highly same as cucumber lipoxygenase-9 , comparabilityreach to 100% ,score is 197 ,the other 3 genes are unknown new genes.(2) The analysis of 4 gotten gene expression speciality show that 49-2 highlyexpressed on leaf in 6h when downy mildew pathogeny bacterium invadecucumber until the evening of the attack, and the express process may be runthrough whole downy mildew invaded period. 50-5 main expressed on leaf in 24hwhen downy mildew pathogeny bacterium attack cucumber, decrease in 48h, andstill express until the evening of the attack. 50-7 only express on cucumber leafon 24h when downy mildew pathogeny bacterium attack cucumber. 52-14 onlyexpress on cucumber leaf on 24h and 48h when downy mildew pathogenybacterium attack cucumber. 49-2 can express on cucumber young fruit andcaducity fruit, 50-5 can express on cucumber young fruit.(3) 4 gotten genes only exist in resist downy mildew variety Dong Nong 129 genome,but inexist in sense downy mildew variety L18 genome. It is show that the geneswe got only exist in cucumber resist downy mildew variety and special expressafter downy mildew attack cucumber. It can be used on molecule filtration ofcucumber downy mildew variety, (4) Construct cucumber mRNA differential display technology reaction system. Thissystem was simple operate and easy repeat. The using amount of cDNA templatedecrease to a half, greatly save work cost. ~...