隐花素在生长素调控拟南芥下胚轴伸长中的作用分析

Effect of Cryptochrome on IAA Regulating Hypocotyls Elongation in Arabidopsis thaliana

以拟南芥野生型(Col-4)和隐花素双突变体cry1cry2为材料,研究不同光照条件下不同浓度吲哚乙酸(IAA)和IAA极性运输抑制剂氨基酞氨酸(NPA)对幼苗下胚轴伸长的影响。结果显示,低浓度IAA(10-7mol/L)可促进连续白光和红光下cry1cry2幼苗下胚轴伸长,而连续蓝光下cry1cry2下胚轴的伸长则受到抑制。蓝光下相同浓度的NPA对cry1cry2幼苗下胚轴伸长的抑制程度比野生型要小。RT-PCR分析结果显示,瞬时蓝光处理时IAA合成关键酶基因IGPS以及生长素应答基因IAA1和IAA5在cry1cry2突变体中的转录水平比野生型中要高。这表明隐花素可能部分通过调节IAA合成和/或IAA极性运输,介导蓝光调控拟南芥下胚轴的伸长。

The wild-type A rabidopsis thaliana ecotypes Columbia （Col-4） and Cryptochrome cry1cry2 double mutants were used to study the effect of indole acetic acid （IAA） and polar auxin transport inhibitor 1-naph- thylphthalamic acid （NPA） on hypocotyl elongation in seedling under different light conditions. The results showed that the hypocotyls elongation of cry1cry2 seedling was stimulated in the presence of low concentra- tion of IAA （10^-7 mol/L） under continuous white and red light, but inhibited under continuous blue light. The hypocotyls elongation of cry1cry2 were less inhibited than that of wild type at relative higher concentration of NPA （5×10^-6 mol/L）. The RT-PCR results exhibited that the expression level of IAA synthesis gene IGPS, and IAA responsive gene IAA 1 and IAA5 in cry1cry2 mutant was higher than that in wild type seedling when exposed to blue light. These results demonstrated that cryptochrome might mediated blue light controlling hypocotyl elongation partly through regulating IAA synthesis and/or IAA polarization in A rabidopsis thaliana.