| Wheat powdery mildew is worldwide disease and is also one of the main diseases of wheat in China. Developing resistance varieties is the most economical, effective and environmental way to control disease. Screening and identification of reisitance materials and genes is the foundation. Rye (Secale cereale L.) as a related species of wheat carries a large number of resistant genes and increasing yield genes. Now, Wheat-rye hetechromosomes play an important role in wheat breeding and identifying the materials genetic background is the foundation, as a middle materials to translate resistance gene on rye. The study on the level of gene expression in wheat resistance mechanism, is the important and few.In the study, offsprings of hybrids BC2F6 between the parents My 15 and rye Rw were taken as test materials. Rw as the donor parent was a Chinese Baili rye (S. cereale L.cv. Baili) inbred lines, because of high resistant to powdery mildew. Meawhile, My 15 as the receptor parent was a common wheat cultivar without any rye chromatin, which was high sensitive to powdery mildew.7 hybrids were selected and identified accuracily with resistance to powdery mildew containing two immune and nerely immune powdery mildew. The mechanism of powdery mildew resistance by assaying expressing of resistance gene.The main results are summaried as follows:1. Identification powdery mildew resistance on 94 BC2F6 hybrids in seeding and adult stage showed that there were 7 hybrids high resistance to disease.2.903-6-1 were immune powdery mildew and 903-6-2 were nearly immune powdery mildew samely hypersensitive response. Based on the results of chromosome karyotype analysis, they were 903-6-1 (2n= 42),903-6-1 (2n=42) and were cytologic satble. Assess of other main agronomic showed that tiller-earing, spikelets, length of spike. Results GISH and SSR analysis showed 903-6-1 and 903-6-2 contained rye chromosomes 1R-7R. Their chromosome configuration was 7"(1-7)R+7"(1-7)B+1"7D+6"A. Identification of FISH probing pSc119.2 and pAs1 showed that:had only a pair of 7D in D genome and all B genome Namely their chromosome configuration were 7"(1-7)R+7"(1-7)B+1"7D+6"A.3. FISH analysis probing pAsl and pSc119.2 on 5 hybids already identified rye chromosomes in order to discuss wheat chromosomes variation after hybiding with rye. The results showed wheat chromosomes had variation while containing rye chromosomes. Only one pair 7D chromosome in D genome in 900-4,900-5 and 912; one pair of ID and 3D chromosomes in 669-2; one strip ID, one pair 2D,3D and 3DS. We made standard banding of inbred Baili rye probing with pSc119.2, which is useful for identifying rye chromosomes. The numbers of chromosome of 669-2,900-4,909,912 were all 2n=44 (except 900-5 was 2n=42). Chromosome configuration of 669-2,900-4,900-5,909,912 respectively was:6"(2-7)R+1" 1D+1" 3D+13"(A+B); 7"(1-7)R+1"7D+13"(A+B); 7"(1-7)R+1"7D+7" (1-7)A+7"(1-7)B;1"1R+5"(3-7R)+1"2D+1"3D+1"3DS+1'1D+ 23'(A+B); 7"(1-7) R+1" 7D+13"(A+B).4. Analysis of powdery mild resistance gene on 903-6-land 903-6-2 having highly similar heredity background but different disease resistance. RT-PCR showed that:PR-1 and Glutathione-S-transferase were irrelevant with powdery mildew resistance; PR-2 and PR-5 could significantly improve the resistance of powdery mildew and participate in the level of nerely immune powdery mildew; Peroxidase and putative cytochrome P450 could also improve the resistance of powdery mildew and putative cytochrome P450 is more obvious role in near immune powdery mildew.The resistanc to to stripe rust, powdery mildew and Fusarium head blight of test martsrails came from Chinese Baili rye cultivar Rw, which could be used as a valuable resistance parent for wheat improvment. The 7 selected materials had high application value, they could be utilized not only as a fine germplasm of disease resistance in wheat breeding but also as forage and grain triticale. Expression model of gene on resistance to powdery mildew was different in immune and nearly immune, which is the useful for powdery mildew resistance. |
PDF Full Text Request