Functional Analysis Of A Histone Deacetylase Gene TaHD2C Of Wheat

A Histone Deacetylase gene TaHD2C, the expression of which has significantly changed in response to salt and drought, was cloned from Shanrong No.3 (SR3), a new somatic hybrid introgression line generated by our lab. TaHD2C overexpression plants delay flowering in both long and short days. This study is conducted to determine the role of TaHD2C in regulating flowering time in Arabidopsis and comes to the following results:1. TaHD2C overexpression plants delay flowering time both in long and short days significantly. The expression of FLC on transcription level declines significantly and expression of relative genes involved in vernalization and autonomous pathway show no significant changes. It is indicated that the late flowering phenotype is unrelated to the expression level of FLC.2. In long days, CO and GI, two genes involved in photoperiod pathway, show no significant changes on transcriptional level. While the expression of FT declines significantly, the expression of downstream genes such as FD, LFY, API also decline on transcriptional level. It suggests that the late flowering phenotype of TaHD2C overexpression plants is likely caused by the lower expression level of FT.3. Transcription factor PIF4 is able to bind to the promoter of FT and induces its transcription. In TaHD2C overexpression plants, the expression of PIF4 declines significantly. SNZ expression declines significantly, from which it is inferred that the expression of miR172 declines. In addition, PIF4 and miR172 regulate the transcription of FT without the presence of CO.4. The late flowering phenotype of TaHD2C overexpression plants can be recovered by spray of GA3. TaHD2C overexpression plants delay in development, decline in floral organs and seed yield.5. In long days, the expression of RGA, RGL1 and RGL2 decline significantly, positive GA biosynthesis enzymes such as GA3oxl, GA20oxl increase in transcription. And the enzyme GA2ox6 catalyzes the conversion of active GA into inactive GA increases in transcription. GA receptor GID1a increases in transcription. It is indicated that GA levels increase.6. TaHD2C overexpression plants are not sensitive to GA or PAC, germination rate in the treatment of PAC is lightly higher than wild type. The aerial part of TaHD2C overexpression plants is smaller than wild type in the treatment of ABA. TaHD2C overexpression plants are not sensitive to mannitol.