| Wheat(Triticum aestivum L.)is one of the crops widely cultivated in the world,and its high and stable yield is very crucial to ensure global food security.Wheat powdery mildew caused by Blumeria graminis f.sp.tritici seriously affected the yield and quality of wheat.Compared with the chemical control means of spraying pesticides in large areas,it is one of the most effective measures to control wheat powdery mildew by constantly exploring and rationally utilizing disease-resistant genes and breeding disease-resistant varieties.The rapid evolution of pathogenic bacteria and the continuous emergence of new virulent isolations have brought new challenges to the control of powdery mildew.Continuous discovery of new resistance genes and analysis of their resistance mechanisms will help to ensure the diversity and persistence of resistance sources.Therefore,in this study,a genetic isolation population was constructed,a variety of hybrid combinations were prepared,and molecular markers were encrypted for fine localization of Pm37.By combining various methods,the wheat powdery mildew resistance gene Pm4 d was cloned,the haplotype of Pm4 site was identified,and the expression of Pm4 after inoculated Bgt was analyzed.The existing wheat secondary gene source materials were screened to further explore the new Pm4 locus haplotype.The main results obtained are as follows:Cloning of Wheat powdery mildew resistance gene Pm GR-18 and exploration of the Pm4 allele in tetraploid wheat.Using resistant wheat GR18-1 and susceptible wheat Xinshiji 156 as parents,163 F2:3 isolated populations were constructed and the resistance genetic analysis was carried out.Combined with BSA and molecular marker encryption analysis,it was located between Xwgrc763 and Xwgrc872,corresponding to the physical interval of about 1.13 Mb of Chinese spring reference genome v2.1,and temporarily named Pm GR-18.Based on homologous cloning and Sanger sequencing analysis,it was found that Pm GR-18 sequence was identical to Pm4 d sequence.The expression patterns of two spliceosomes Pm4d_V1 and Pm4d_V2 in GR-18 were analyzed by q PCR after inoculation of wheat white bacterium E09.It was found that the expression level of Pm4d_V2 was significantly lower than that of Pm4d_V1 at most time points.Markers JS717/JS718 was used to screen cloned genes in the A genome of 260 tetraploid materials,including emmer wheat,and it was found that 13 tetraploid materials contained Pm4 gene.Wheat material containing Pm4 was cloned and its sequence was analyzed.The wheat materials containing Pm4 were cloned,and the sequence analysis showed that Pm4 a was carried in 13 materials,Pm4 b in 6 materials,Pm4 d in 1 material and Pm4 f in 1 material.Fine mapping of powdery mildew resistance gene Pm37 in wheat.The results showed that Pm37 exhibited excellent resistance to 32 different Bgt strains.Wheat 66,which carries Pm37,was used as the resistance parent,and was crossed with susceptible varieties Ningmai13 to construct the 2662 F2:3 genetic isolation population for resistance genetic analysis.Based on the polymorphic molecular markers developed by large population isolation and BSR-seq sequencing analysis,23 molecular markers linked to Pm37 were screened.Pm37 was located between flanking markers Pm37-151 and Pm37-7,and compared with Chinese spring reference genome V1.0 published by IWGSC,it was located on the 7AL chromosome arm of wheat with the corresponding physical distance of 455.44 kb.A total of 4genes related to plant disease resistance were annotated in the interval,Traes CS7A01G499700,Traes CS7A01G499900,Traes CS7A01G499400,Traes CS7A01G499600 were annotated in the interval.Molecular markers Pm37-18,Pm37-82,Pm37-HHG2 and Pm37-HHG6 were selected for MAS analysis of 46 Chinese wheat varieties/breeding lines.The above four molecular markers can effectively detect polymorphisms between susceptible materials and materials carrying Pm37.These four molecular markers can be used to detect whether Pm37 is introduced into the target material by cross-fertilize. |
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