Roots navigate around decay regions by sensing local pH gradients

article Roots navigate around decay regions by sensing local pH gradients published yes Zhulatai Bao author Huihui Wang author Ai Zhang author Ruxi Gao author Wen Gu author Ni Fan author Jiří Friml author 4159519E-F248-11E8-B48F-1D18A9856A870000-0002-8302-7596 Yuzhou Zhang author JiFr department Cyclic nucleotides as second messengers in plants project Guanylate cyclase activity of TIR1/AFBs auxin receptors project 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. American Association for the Advancement of Science2026 eng Science 0036-8075 1095-9203 4242447210.1126/science.adw6568 3936807 Bao, Zhulatai, et al. “Roots Navigate around Decay Regions by Sensing Local PH Gradients.” Science, vol. 393, no. 6807, eadw6568, American Association for the Advancement of Science, 2026, doi:<a href="https://doi.org/10.1126/science.adw6568">10.1126/science.adw6568</a>. Bao Z, Wang H, Zhang A, et al. Roots navigate around decay regions by sensing local pH gradients. Science. 2026;393(6807). doi:<a href="https://doi.org/10.1126/science.adw6568">10.1126/science.adw6568</a> Bao Z, Wang H, Zhang A, Gao R, Gu W, Fan N, Friml J, Zhang Y. 2026. Roots navigate around decay regions by sensing local pH gradients. Science. 393(6807), eadw6568. Z. Bao, H. Wang, A. Zhang, R. Gao, W. Gu, N. Fan, J. Friml, Y. Zhang, Science 393 (2026). Bao, Z., Wang, H., Zhang, A., Gao, R., Gu, W., Fan, N., … Zhang, Y. (2026). Roots navigate around decay regions by sensing local pH gradients. Science. American Association for the Advancement of Science. <a href="https://doi.org/10.1126/science.adw6568">https://doi.org/10.1126/science.adw6568</a> Bao, Zhulatai, Huihui Wang, Ai Zhang, Ruxi Gao, Wen Gu, Ni Fan, Jiří Friml, and Yuzhou Zhang. “Roots Navigate around Decay Regions by Sensing Local PH Gradients.” Science. American Association for the Advancement of Science, 2026. <a href="https://doi.org/10.1126/science.adw6568">https://doi.org/10.1126/science.adw6568</a>. Z. Bao et al., “Roots navigate around decay regions by sensing local pH gradients,” Science, vol. 393, no. 6807. American Association for the Advancement of Science, 2026. 223152026-07-13T14:57:10Z2026-07-14T08:11:55Z