Work

Directed Evolution of Plant‐Associated Bacteria Enhances Plant Holobiont Stress Tolerance

Year: 2026

Type: article

Abstract: Plant stress responses are shaped by both the plant genome and its associated microbial communities, which together form the plant holobiont. Given the rapid adaptive potential of plant-associated microbes, we hypothesised that directed evolution under selective pressure can accelerate the development of holobiont-level stress tolerance. Directed evolution of the plant-associated bacterium Bacillus subtilis MR21 produced three evolved strains (EV1-EV3) with distinct plant-beneficial traits. These strains enhanced coriander growth under conditions of lead (Pb) toxicity and micronutrient deficiency. The evolved bacteria improved rhizosphere conditions by reducing Pb availability and increasing the availability of essential nutrients, including phosphorus, iron and zinc, thereby enhancing plant holobiont stress tolerance. In addition, rhizosphere detoxification and elevated production of organic acids, such as succinic and glutamic acid, contributed to improved soil chemical conditions. Together, these processes promoted a by-product mutualism within the rhizosphere, in which detoxifying bacteria indirectly supported less beneficial members of the microbial community. We conclude that directed evolution of plant-associated bacteria provides a natural and efficient strategy to enhance plant stress tolerance at the holobiont level, offering a complementary approach to conventional breeding and genetic engineering.

Source: Plant Cell & Environment

DOI: 10.1111/pce.70710

Authors: Mohammadhossein Ravanbakhsh, Wu Xiong

Institutions: Utrecht University, Nanjing Agricultural University

Language: English

Topic: Plant-Microbe Interactions and Immunity

Subfield: Plant Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: hybrid

Estimated APC paid: $5,440