乙醇对拟南芥主根生长发育的影响

Effect of ethanol on the growth and development of primary roots in Arabidopsis thaliana

乙醇是植物厌氧发酵产物,参与胁迫响应和信号转导,但其在植物根生长发育中的作用未阐明。我们发现乙醇能以浓度依赖的方式抑制拟南芥主根和分生组织的生长,移苗结果显示乙醇在高浓度时能抑制根尖分生组织CYCB1;1::GUS和静止中心标记系QC25的表达,说明较高浓度乙醇能通过抑制分生组织活性和干细胞活性来抑制拟南芥主根的生长。进一步研究发现高浓度乙醇能抑制根尖DR5::GUS和DR5::GFP的表达,taa1-1突变体对乙醇抑制的主根生长更敏感,而yuc1D生长素过量合成株系减缓乙醇对根生长的抑制作用,且qRT-PCR结果显示乙醇能下调生长素合成基因TAA1、ASA1和YUC5的表达,同时降低生长素极性运输蛋白PIN2的表达。研究结果表明,较高浓度的乙醇可能通过抑制拟南芥主根尖分生组织和干细胞活性、生长素合成以及生长素极性运输,从而抑制拟南芥主根的生长发育。

Ethanol is a product of anaerobic fermentation in plants,which is involved in stress response and signal transduction,but its role in plant root growth and development has not been clarified.We found that ethanol inhibited the growth of primary roots and meristems in a concentration-dependent manner.The transplant seedling results showed that high concentration ethanol inhibited the expression of CYCB1;1::GUS and QC25 in root apical meristems,indicating that higher concentration of ethanol can inhibit primary root growth by inhibiting meristem activity and stem cell activity in Arabidopsis.Further studies showed that high concentration of ethanol inhibited the expression of DR5::GFP and DR5::GUS in root tips.The taa1-1 mutant was more sensitive to ethanol-inhibited primary root growth,while the auxin overproduction line yuc1D attenuated the inhibitory effect of ethanol on root growth.The qRT-PCR results showed that ethanol down-regulated the expression of auxin synthesis genes TAA1,ASA1 and YUC5,and ethanol can also reduce the expression of auxin polar transport protein PIN2.Our results suggest that higher concentration of ethanol may inhibit the growth and development of Arabidopsis primary roots by inhibiting the meristem activity,stem cell activity,auxin synthesis,and auxin polar transporter protein expression.