Transcriptome Analysis Of Stripe Rust Resistance Conditioned By YrAS2388 And Gene Pyramiding For Durable Resistance

Wheat stripe rust,caused by(Puccinia striiformis f.sp.tritici,Pst)is an important fungul disease that caused serious yield losses in wheat.YrAS2388 confers resistance to a range of Pst isolates.This gene provides all-stage resistance in Aegilops tauschii,while partially resistance in synthetic hexaploid wheat Syn-SAU-93.YrAS2388 encodes a typical nucleotide oligomerization domain-like receptor(NLR),whereas has duplicated 3’untranslated regions.The resistance mechanism of YrAS2388 to Pst is still unknown.In the current study,we have deciphered the stripe rust resistance conditioned by YrAS2388 using transcriptome approach and pyramided the YrAS2388 with other partial Yr genes in wheat background.The main result are as follows:(1)The synthetic wheat Syn-SAU-93 with YrAS2388 showed completely susceptible to Pst at seeding stage,whereas partial resistance at adult plant stage.The average expression level of YrAS2388 and PR genes in Aegilops tauschii genotype AS2388 was higher than that of in Syn-SAU-93.YrAS2388 was expressed in roots,stems,leaves and spikes,while leaves had the highest expression level.YrAS2388 was up-regulated by Pst inoculation.A total of 979 differentially expressed genes(DEGs) responsive to Pst infection were identified.The majority of DEGs were primarily involved in surveillance pathway(58 DEGs),phenylpropanoid biosynthesis(55 DEGs),plant-pathogen interaction(52 DEGs),MAPK signaling pathway-plant(49 DEGs),starch and sucrose metabolism(37DEGs).479 out of 979 DEGs had higer expression levles in diploid Aegilops tauschii than those of in synthetic hexaploid wheat.(2)The Yr36,YrAS2388,and Yr18 genes confer partial and a broad-spectrum stripe rust resistance were transferred into new elite wheat lines Shumai969 and Shumai830 for the purpose of durable resistance breeding.We have obtained wheat lines that pyramided three Yr genes in Shumai969 and Shumai830 background.Field stripe rust resistance test indicated that the pyramiding of Yr36,YrAS2388,and Yr18 genes could enhance the stripe rust resistance of susceptible wheat Shumai969,while no obvious resistance differences were obsevered between Shumai830 and its three genes pyramiding lines.(3)The Yr18,YrAS2388 and Yr36 were sucessfully transferred into wheat line SY95-71,a susceptible spreader for resistance identification of stripe rust,for the purpose of resistance genetic study.We have obtained wheat lines with different Yr gene combination(Yr18,Yr36,YrAS2388,Yr18+Yr36,Yr18+YrAS2388,YrAS2388+Yr36 and Yr18+YrAS2388+Yr36)in SY95-71 background.Field stripe rust resistance test indicated that pyramiding of Yr gene could improve the resistance of SY95-71.The resistance level of single Yr gene transfer in SY95-71 was Yr18 > Yr36 > YrAS2388.The resistance level of different Yr genes combinations in SY95-71 was Yr18+YrAS2388+Yr36 > Yr18+Yr36 >Yr18+YrAS2388 > YrAS2388+Yr36.