小麦4-羟基苯丙酮酸双氧化酶(TaHPPD)基因克隆与功能鉴定OA

In order to clarify the characteristics and functions of the wheat herbicide target gene HPPD,the wheat HPPD genes were cloned,and sequence analysis,expression feature analysis,subcellular localization,prokaryotic expres-sion,enzymatic activity assays and functional analysis of the wheat HPPD genes were conducted in this study.The results showed that there were three HPPD alleles in wheat,which were located on chromosomes 6A,6B and 6D,respectively,and TaHPPD-A was closely related to TaHPPD-B.The TaHPPD promoter contained a large number of light response ele-ments and stress response elements.After 12 h of light treatment,the expression levels of TaHPPD-A and TaHPPD-D decreased by 80.9%and 63.3%,respective-ly,compared with the end of dark treatment(control).After 24 h of light treatment,the expression levels of TaH-PPD-A,TaHPPD-B and TaHPPD-D decreased by 88.1%,40.4%and 63.6%,respectively,compared with the control.The expression of TaHPPD was induced by stress conditions such as Fusarium head blight,stripe rust and drought.Subcellular localization analysis showed that TaHPPD-A protein was located in cytoplasm and chloroplast,while TaHPPD-D protein was only located in chloroplast.TaHPPD protein retained chromogenic activity even in a high-concentration mesotrione chromogenic solution.However,its protein expression level was significantly higher than that of corn HPPD protein and rice HPPD protein,while HPPD enzyme activity of wheat was significantly lower than that of rice and corn.Compared with the wild type rice Zhonghua11,the resistance indices of the three TaHPPD overexpression plants(TaHPPD-A-OE-18,TaHPPD-B-OE-7 and TaHPPD-D-OE-7)with the highest rela-tive expression level were 13.92,15.66 and 7.63,respectively.The results of this study provide a basis for the development of wheat germplasm resistant to HPPD inhibitor herbicides.