Primary Mapping Of Resistance Gene To Sitobion Avenae In Mazhamai And Functional Analysis Of The Resistance-related Gene TtLOX In Lanmai

The English Aphid?EGA,Sitobion avenae,Fabricius?is the dominant population of wheat aphids in the Northern and Huang-huai wheat regions of China,which seriously affects the yield and quality of wheat.However,there are few studies on resistance genes and mechanism of S.avenae in wheat,and the resistance gene resources are very important for improving wheat quality and yield.In order to further study the resistance mechanism of wheat to S.avenae,the genetic map populations of F₂and F_2:3were constructed from the progenies of aphid-resistantvariety Mazhamai and aphid-sensitive variety Xinong 1376,and the candidate regions of the target gene were determined via SNP and bulked segregate analysis.The anti-aphid related gene Tt LOX was isolated from Lanmai?Triticum Turgidum,AABB??Zhashui,Shannxi?and its anti-aphid function was validated.The results are as follows:The genetic analysis showed that the genetic mode of resistance to aphids of Mazhamai was dominant inheritance controlled by single gene.The resistance ratio of F₂and F_2:3was1:2:1 and following chi-square distribution and showed thequality signal of anti-susceptibility double-peak.The 55K genotyping chip was used to detect the SNPs enrichment sites,which showed that differential SNPs were highly enriched on chromosomes 6A,7A,2B and 5A,with the highest concentration on chromosome 6A,and the differential SNPs on chromosome 6A were enriched in several candidate regions.The Tt LOX has a 2787 bp open reading frame or 928 amino acid residues,and its molecular weight is 105.45 k Da.Bioinformatics analysis showed that the gene was a member of the 13-lipoxygenase?13-LOX?superfamily,and its protein sequence was very similar to that of lipoxygenase in many plants;The Tt LOX was located in the nucleus and cell membrane by subcellular localization,and the expression level of the gene was higher in aphid-resistant wheat?Lanmai?than in aphid-susceptible?Poland 305,Triticum polonicum L?.The results of methyl jasmonate treatment showed that this gene was associated with resistance to wheat aphid and involved in jasmonate biosynthesis pathway.The Tt LOX gene silenced by barley stripe mosaic virus?BSMV?,the results showed that the ability of plant resistance to aphids was significantly decreased after the gene was silenced.Genetic analysis and 55k chip genotyping of the resistance gene to Sitobion avenae,and successful cloning and verification of Tt LOX,provided new genetic resources for further isolation of resistence gene and selection of aphid resistant varieties,it provided a new way and thought for analyzing the mechanism of wheat resistance to Sitobion avenae.