Integrated application of synthetic community reduces consumption of herbicide in field Phalaris minor control

To address environmental concerns and manage resistant weeds, there is a growing demand for eco-friendly alternatives. In this study, we propose the integration of synthetic communities (SynComs) to reduce herbicide consumption. Four SynComs, consisting of bacteria isolated from weed or wheat rhizospheres, were first evaluated under greenhouse conditions. All SynComs enhanced wheat growth, which was manifested by increased Soil Plant Analysis Development (SPAD) values and fresh biomass. At the same time, SynCom C4 effectively reduced SPAD values and fresh biomass of the infesting weed, Phalaris minor, when combined with low-dose Axial herbicide. A field trial was then conducted using the C4 SynCom and various doses of Axial (100%, 75%, 50%, and 25%). Remarkably, the combination of C4 with 50% and 75% Axial significantly improved wheat growth by mitigating the side effects of herbicide on wheat. Weed infestation reduced grain yield by 16% and 25% at the dose of 50% and 75% Axial, respectively. The combination of Axial with C4 rescued up to 22% of grain yield loss under infested weed compared with Axial alone. Our findings suggested that the combination of herbicides with SynComs exhibited synergistic effects for controlling Phalaris minor and promoting wheat growth, so that such combination provides a sustainable and eco-friendly weed control strategy.