脱落酸通过影响生长素合成及分布抑制拟南芥主根伸长

脱落酸(ABA)在介导植物生长发育及逆境响应中发挥重要功能,但ABA抑制根伸长的机制尚不清楚。本文以拟南芥为材料,通过研究ABA对拟南芥根伸长的影响以及ABA受体突变体根发育表型的鉴定,探讨ABA抑制植物主根的机制。研究发现:ABA能够抑制主根生长及伸长,并且经典受体PYR1/PRL介导了ABA抑制根伸长的过程;ABA能够改变细胞周期蛋白CycB1;1::GUS表达模式,并影响根中生长素分布和响应。结果表明,ABA可能通过影响生长素在根部的分布和剂量,进而影响根尖分生区细胞分裂,从而抑制根伸长。

ABA modulates root growth through regulating auxin in Arabidopsis thaliana

As sessile organism, plants exhibit an amazing developmental plasticity in adapting to changing growth conditions in response to environmental stimuli. As an important organ of plants, roots variously make active changes in the face of different stimuli. It is well known that ABA (abscisic acid) is an important molecule that inhibits root growth. ABA receptor PYR1/PYL mediates ABA signaling transduction by binding with PP2C proteins and activating kinases SnRK2s. However, little is known about how ABA regulates root growth and plastic development. In order to understand the mechanism underlying root growth inhibition by ABA, the effects of ABA on the size and activity of root meristem, meristematic cell cycle, and auxin amount and distribution patterns were analyzed with Arabidopsis thaliana as materials. The results showed that ABA inhibited the growth of primary roots and reduced the size of meristems of primary roots. The inhibition effect of ABA on pyr1/pyl1/pyl2 root growth reduced, which showed that ABA receptor PYR1/PYL was involved in the inhibition of root growth. Further analysis showed that ABA treatment blocked G2/M-phase transition during cell division with the accumulation of cyclin proteinCYCB1;1::GUS expression. In addition, we noted that the amounts and distribution patterns of auxin in the roots changed with treatment of ABA. The results suggested that ABA inhibited the growth of roots by modulating synthesis and auxin response which in turn influenced cell division in root meristem.