异三聚体G蛋白在2,4-D诱导的拟南芥根生长发育中的作用

The Role of Heterotrimeric G Protein in 2,4-D Induction,Growth and Development of Arabidopsis thaliana Roots

利用拟南芥的野生型(ws)、异三聚体G蛋白α亚基基因GPA1缺失突变体(gpa1-1和gpa1-2)和超表达突变体(wGα和cGα)为材料,通过施加不同质量浓度(0～0.010 mg.L-1)的2,4-D处理,对拟南芥根生长发育的形态指标进行了测定。结果表明:(1)随着培养基中2,4-D质量浓度的不断增大,5种基因型主根的伸长生长都受到抑制,且抑制作用随浓度升高而增强;4种突变体和野生型主根的生长在相同浓度2,4-D处理下,无明显差异;(2)2,4-D在一定浓度范围内,对拟南芥侧根的生长发育起促进作用;在2,4-D诱导的侧根生长中,相同浓度2,4-D处理下,缺失突变体明显比野生型侧根多,超表达突变体比野生型侧根少;gpa1-1和gpa1-2分别在2,4-D质量浓度为0.005mg.L-1和0.008 mg.L-1时的侧根数目与野生型差异最大。初步证明G蛋白不参与2,4-D诱导的拟南芥主根生长发育的调节,而在侧根生长发育中可能起负调节作用。

Wild type （ws） Arabidopsis thaliana, two null mutants of G protein a subunit gene （gpα1-1 and gpα1-2） and two over-expressed mutants of G protein a subunit gene （wCα and cGα） were treated with 2, 4-D at different concentrations （0-0. 010 mg · L^-1） to comparatively examine some morphological parameters related to growth and development of the roots. It was observed that （1） increasing concentration of 2,4-D inhibited elongation of the taproots in a dose-dependent way. No differences were recorded between the ws and the four mutants（2） within a certain range of concentration, 2,4-D showed promoting effect on the growth and development of the lateral roots. Under the same concentration of 2,4-D the numbers of the lateral roots were higher in null mutants and lower in over-expressed mutants, with reference to the wild type. The numbers of the lateral roots had the highest differences between the gpα1-2 ,gpα1-1 and the ws at 0. 005 mg · L^-1 and 0. 008 mg · L^-1 2,4-D concentrations. It is concluded that the a subunit of G protein had no effect on the grow of taproot promoted by 2,4-D, while playing a negative regulation role in the growth of lateral roots.