Microbial acetyl-CoA synthesis as an emerging metabolic and regulatory hub in plant-microbe interactions

Acetyl-CoA synthetase (ACS) is a well-characterized enzyme that catalyzes the ATP-dependent ligation of acetate and coenzyme A to produce acetyl-CoA, a central metabolite coordinating energy metabolism, carbon flux distribution, and post-translational protein modification. Recently, ACS has emerged as a metabolic nexus with broad implications for plant-microbe interactions in agriculture. Beyond its canonical role in primary metabolism, ACS governs diverse physiological processes in beneficial plant-associated microorganisms, including rhizosphere colonization, stress adaptation, secondary metabolite biosynthesis, and morphological development-all of which enhance plant growth and resilience. In contrast, in phytopathogens, ACS is closely related to the expression of virulence factors. Thus, ACS exerts a dual influence, shaping both mutualistic and antagonistic microbial lifestyles in planta. This review synthesizes recent advances in the structural and catalytic diversity of ACS, delineates its ecological and functional roles in agriculturally relevant microorganisms, and explores the environmental and host-derived signals that regulates its expression and activity. Particular attention is given to the interplay between ACS-mediated carbon metabolism and protein acetylation, which together modulate microbial physiology and plant-associated behaviors. ACS is thereby positioned as a strategic metabolic hub, providing a framework for future research at the interface of microbial metabolism, environmental adaptation, and plant health.