Functional Analysis Of Gibberellin Oxidase Gene MtGA20ox In Medicago Truncatula

Plant height plays an important role in many factors that determine the yield of pasture.There are also many factors that decide the traits of plant height.One of the five major plant hormones,gibberellic acid(GA),is essential for the regulation of plant height.GA20-oxidase(GA20ox)is a key rate-limiting enzyme in the synthesis of gibberellic acid.The studies on GA20-oxidase in forage legumes is poorly understood.This paper makes a preliminary research on the regulation of GA20 ox gene on plant height in Medicago truncatula.The main results are as follows:1.The amino acid sequence alignment of GA20 ox of Arabidopsis thaliana and Medicago truncatula was carried out by bioinformatics methods,and the phylogenetic tree of the families was constructed.The results showed that there were three MtGA20ox,which were Mt GA20ox1,Mt GA20ox7 and Mt GA20ox8,respectively.They had highly homologous to At GA20 ox,and each of them contained a conserved 20G-Fe II_Oxy domain.2.Further,the results of transcript analysis indicated that the expressions of Mt GA20ox1,Mt GA20ox7 and Mt GA20ox8 were tissue specific.3.Meanwhile,the result of subcellular localization indicated that Mt GA20ox1,Mt GA20ox7 and Mt GA20ox8 proteins were probably localized in nucleus and cytoplasm.4.In order to comprehend the function of MtGA20ox,two mutants with retrotransposon Tnt1 inserted in Mt GA20ox7 and one mutant with retrotransposon Tnt1 inserted in Mt GA20ox8 were obtained.The phenotypic observations and data statistics of the three mutants manifested that there were no significant changes in the plant height compared with the wild type.This might be due to the functional redundancy of the three MtGA20ox genes.Results of this study had a certain reference value for studying the function of GA20 ox and the regulation of gibberellin on plant height in Medicago truncatula.