版纳植物园揭示锌毒害调控植物根系发育的生理与分子机制

　锌(Zn)是动植物体内必需的微量元素，适量的锌促进植物生长、提高作物产量；然而高浓度Zn则对植物有害。中国科学院西双版纳热带植物园园艺植物育种研究组前期研究发现，锌毒害通过调控NO/ROS信号途径，影响了根系构型，但其中详细的生理与分子机制尚不完全清楚。

    该研究组研究生张苹、孙亮亮在研究员徐进的指导下，以拟南芥为材料，采用植物生理学、药理学、遗传学和分子生物学等研究手段，对锌毒害调控植物根系发育的生理与分子机制进行深入研究。研究表明，过量Zn通过调控PIN4蛋白的丰度，影响根尖生长素的累积。进一步研究发现，过量Zn提高根系cGMP的水平。cGMP通过调控NO合成，进而影响ROS累积和随后的根尖PCD发生。同时，cGMP影响根尖PIN4蛋白的丰度，从而调节根尖生长素的累积，最终影响根系发育。

　　相关研究成果以cGMP is involved in Zn tolerance through PIN4-mediated auxin redistribution in root tips为题，发表在Environmental and Experimental Botany上。研究工作得到了国家自然科学基金、云南省中青年学术带头人后备人才、国家重点研发计划等的资助。

锌毒害影响根系发育

 

cGMP is involved in Zn tolerance through the modulation of auxin redistribution in root tips

Abstract

Excess zinc (Zn) inhibits primary root (PR) growth but induces lateral root (LR) formation. Both auxin and cGMP play a role in controlling root growth in plants. However, whether and how their interaction is involved in Zn-regulated root development remain unclear. Here, we reported that excess Zn leads to auxin accumulation in root tips, as indicated by DR5:GUS expression. Further study showed that excess Zn represses PIN4:GFP abundance in root tips and that PR elongation and LR formation in the pin4mutant is insensitive to excess Zn. Excess Zn also elevates cyclic guanosine monophosphate (cGMP) production in seedlings. Supplementation with the exogenous cGMP donor 8-bromoguanosine 3′,5′-cyclic guanosine monophosphate (8-Br-cGMP) increased PR elongation and LR formation in Zn-treated seedlings, whereas the guanylate cyclase (GC) inhibitor LY83583 decreased these processes. Additional physiological and genetic analyses indicated that PIN4 is involved in cGMP-modulated root development in Zn-treated seedlings. Taken together, these results indicate that Zn-regulated cGMP production plays an important role in modulating root development by maintaining PIN4 abundance in excess Zn-treated roots and subsequent adaptation to Zn toxicity.