The Innovation Team of Soil-Plant Interactions at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) has published their latest research, "A rhizobacterium-secreted protein induces lateral root development through the IAA34-PUCHI pathway", in the Cell Reports journal.

Plants develop lateral roots to acquire nutrients and water from the surrounding environment for their growth and development. Soil microbiota living around plant roots have a positive impact on the root development of host plants, but the regulatory mechanisms are still unclear.

The study found that the model rhizobacterium Bacillus velezensis SQR9 can promote plant lateral root development without relying on the canonical auxin signaling pathway involving the ARF7 and ARF19 transcription factors. Researchers isolated and purified an active protein, bacillolysin, from the fermentation broth supernatant of SQR9 based on bioactivity tracking methods. This protein induced lateral root development by recognizing the receptor CEPR2 at the host root tip, mediating downstream non-canonical auxin signaling module "IAA34-PUCHI." The study demonstrates that active substances from rhizosphere microbes can induce lateral root generation through specific response pathways, providing important theoretical support for the development of novel microbial fertilizers based on active substances from rhizosphere microbes.

Figure 1: Mechanism model of Bacillus sp. active substances promoting lateral root development

Doctoral student Fu Yansong from Nanjing Agricultural University and Researcher Liu Yunpeng from the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, are co-first authors of the paper, with Researcher Zhang Ruifu as the corresponding author. This research received support from the National Key Laboratory for Efficient Utilization of Dryland in Northern China, the National Key Research and Development Program, the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences, and the Youth Innovation Special Fund of the Chinese Academy of Agricultural Sciences.

Article link: https://doi.org/10.1016/j.celrep.2025.115414