| Wheat powdery mildew is a severe foliar destructive disease caused by Blumeriagraminis f. sp. Tritici (Bgt). Bgt is an obligate parasite and has many different races.Pm21, aresistant gene discoverd and utilized firstly by Chinese scientist, has broad-spectrum ability toresist powdery mildew. The gene located originally at shord arm of6V in Haynaldia villosa(2n=2x=14, VV), and it was translocated into wheat. The gene is immune to most availableisolates of Bgt in China and120more races in Europe.In this research, wheat cultivar‘Bainong’, which is susceptible to Bgt, and its near-isogenic line with a resistance gene Pm21were used. Microscopic differences were analysised after infection and disease-resistantcharacteristic were determined. In order to understand the resistant mechanism of Pm21andobtain the important functional proteins, differencial proteins were detected and determinedby protemics technologies. Besides, among the candidate genes which might be releated withpowdery mildew resistance, a TaPRP gene were cloned and transformed into tabacco, andinitial study were conducted on the transgenic plants.This research has an important significance in powdery mildew resistance andmolecular breeding in wheat and it will helpful for clarifying disease-resistant mechanism inwheat powdery mildew and for improve the disease-resistance in wheat by biologicalengineering technology.Main results were listed as follow:1.Microscopic observation results showed that Bgt spores displayed no differences on leavesurface between Bainong3217and its near-isogenic line with a resistance gene Pm21atearly stage of inoculation. Leave cell surface in Bainong3217folded near the spores after12hr,but no fold was discovered in its near-isogenic line.Hyphae covered leaf surface inBainong3217, but the growth of Bgt spores were significantly inhibited in near-isogenic‘Bainong3217’after infection. Besides, hypersensitive reaction was found at the4th day afterinoculation.2.After inoculation by Bgt, total proteins were extracted at6h,96h, and membrane proteinswere extracted at4h. Proteins were sepoerated well by2D electrophyresis. Comparing the2Dmaps of in the two lines,51,97,45and13differential expressed proteins were detemined.Among these differential proteins,104proteins reached to2-fold differences.3.A total of49proteins had been analyzed by mass spectra and were identified by database.Among the49determined proteins,14proteins were detected to be related to photosynthesisand photorespiration. The up regulation proteins contained ribulose-1,5-bisphosphate carboxylase, large subunit and small subunit, carboxylase/oxygenase small subunit，chloroplastic glutamine synthetase leaf isozyme, serine-glyoxylate aminotransferase, Putativeglucan endo-1,3-beta-D-glucosidase precursor,Ascorbate peroxidase and so on.Besides, somerelevant resistant-disease proteins might affect regulatory resistant-disease machanism, suchas G-protein subunit, BTB/POZ domain containing protein, Zinc finger, NAC transcriptionfactor, CALMODULIN antagonist/calcium-dependent protein kinase substrate.4.According to above detemined proteins, a proline rich protein (PRP) was cloned byRT-PCR. Nucleotide sequence analysis showed TaPRP is composed of1137bp and378amino acid residues. TaPRP gene was transformed into Tobaccos byAgrobacterium-mediated technique. Three transgenic lines were obtained. The transgeniclines were tested for cold tolerance following the leaf cell membrane thermostability test.Results showed that the transgenic lines improved cell membrane stability as compared to thewild type. Besides, the different transgenic lines showed significant variation in cold tolerance,and significant interactions between plants and treatment temperatures. |
