论文题目：Roots navigate around decay regions by sensing local pH gradients
论文作者：Zhulatai Bao， Huihui Wang , Ai Zhang, Ruxi Gao , Wen Gu, Ni Fan,Jiří Friml, Yuzhou Zhang*
论文摘要：Plant tropisms enable roots to navigate complex soils by responding to directional environmental cues. Biological decay, although central to nutrient cycling, also creates microbially active and potentially hostile niches. In this work, we identified “saprotropism,” a previously unrecognized growth response that enables roots to actively bend away from decaying plant-derived matter. Fungal-driven microbial decomposition released organic acids and formed stable pH gradients in surrounding soil, allowing roots to pinpoint decay without direct contact. Root epidermal cells sensed this acidic gradient through the root meristem growth factor peptide-receptor module, converting external pH asymmetry into asymmetric abscisic acid (ABA) distribution. ABA asymmetry drove microtubule reorganization, which was decoded into decay-avoidant root bending. Together, these findings establish microbial decay–derived chemical gradients as an instructive signal for root navigation and expand the framework of microbe-soil-plant communication.
植物向性使根系能够响应具有方向性的环境信号，在复杂土壤环境中实现定向生长。生物腐败虽然是生态系统养分循环的核心过程，但同时也会形成微生物高度活跃、对植物具有潜在危害的生态位。本研究鉴定了一种此前未被认识的植物生长响应——“避腐性”（saprotropism），使植物根系能够主动弯曲并避开植物来源的腐败物。我们发现，真菌驱动的植物残体腐解过程释放大量有机酸，在周围土壤中形成稳定的酸性 pH 梯度，使根系无需直接接触腐败物即可准确感知其位置。根表皮细胞通过根分生组织生长因子（RGF）肽–受体（RGFR）信号模块感知这一酸性梯度，并将胞外 pH 的不对称性转化为植物体内脱落酸（ABA）的不对称分布。ABA 信号的不对称进一步驱动皮层微管重排，最终被转化为引导根系远离腐败区域的定向弯曲生长。综上，本研究确立了微生物腐败产生的化学梯度作为引导植物根系导航的重要环境信号，并拓展了人们对微生物—土壤—植物相互作用机制的认识。
论文链接：https://www.science.org/doi/10.1126/science.adw6568