Analysis Of Yield And Drought-related Gene Expression Of The New Wheat Variety Yannong 1212

Wheat is an important food and economic crop.At present,due to the frequent natural disasters,the reduction of arable land and the loss of farming labouers,the production of wheat faces more chanllenge to meet the needs of human beings.Therefore,wheat germplasm improvement has become the main direction of research in wheat.At present,the genetic improvement of wheat still relines on traditional breeding techniques.Due to the time consuming breeding procedure,the heavy workload,and easily affected by external environmental factors,the current progress of wheat germplasm improvement is slow and ineffective.With the rapid development of molecular biology technology,it is of great significance for the improvement of wheat germplasm through genetic manipulation of key genes regulating yield and stress tolerance.Yannong 1212 is a new wheat variety resently developed by Yantai Agricultural Science Research Institute.This variety is highly disease resistant,with high yield potential and extensive regional adaptability.As it is developed using traditional breeding method,little is know about the molecular mechanism regulating of its favorable performance such as high yield and good stress tolerance.This limits the further use of this variety as good germplasm resources.In this work,I clonedthe TaGW2 gene for the A,B,D subgenomes in nine wheat varieties,Yannong 1212,Jimai 22,Yan 2415,Yannong 999,Yannong 15,Shengmai 127,Zhengmai 9023,Hengjinmai 8 and Pingan 11.Multiple sequence alighment was used to detect thesequence differences among different varieties.Correlation analysis of grain weight and sequence variation was also conducted.In addition,expression profiles of the four important yield and drought resistance related genes,GW2,GS1,BADH and DREB was carried out for Yannong 1212 and the control variety Jimai 22 using RT-qPCR.The main results are as follows:(1)The TaGW2-A/B/D gene(except main part of intron 6)sequences of 9 cultivars(Yannong 1212,Jimai 22,Yan 2415,Yannong 999,Yannong 15,Shengmai 127,Zhengmai9023,Hengjinmai 8,Pingan 11)were cloned successfully.(2)By comparing the TaGW2 gene sequences of nine wheat varieties,three or lessSNPs were found in varieties with small or medium grain(apart from Yan 2415),while5 to 6 SNPs were detected in varieties with large grain such as Hengjinmai 8 and Pingan11.These SNPs or mutations may lead to the loss of TaGW2 gene function,correspond to grain size.In addition,markable changes of TaGW2 expression during seed development period was observed,suggesting that TaGW2 gene may closely related to grain size,and might beone of the important factors leading to the difference in the 1000-grain weight of these nine varieties.(3)Varieties Yannong 1212 and Yannong 999 still showed excellent yield characters even if no SNPs leading to the loss of TaGW2 gene function was detected,indicating that there should be some other beneficial genes contributing to grain yield.Genetic manipulation such as gene editing of TaGW2 in Yannong 1212 and Yannong 999 to get loss of function mutations would be possible to further increase their yield potential.(4)By comparing the expression levels of TaGW2 gene between Yannong 1212 and Jimai 22,we found that the expression of TaGW2-D was significantly higher than that of TaGW2-A and TaGW2-B,suggesting that the contribution of TaGW2-D to yield is higher than that of TaGW2-A and TaGW2-B.(5)The expression of TaGS1 a gene varied greatly during grain development,suggesting that TaGS1 a may be closely related to grain development.The expression of TaGS1 a gene was higher in Yannong 1212 than in Jimai 22 during grain development,indicating that Yannong 1212 used more nitrogen than Jimai 22 during grain development,and Yannong 1212 was a better germplasm resource.(6)High expression of BADH and DERB genes were detected in Yannong 1212 and Jimai 22 after drought treatment,indicating that these two genes may be closely related to drought resistance.The expression of BADH gene and DERB gene in Yannong 1212 was higher than that in Jimai 22 under the same treatment,which corresponded to the high stress resistance of Yannong 1212.