Recent advances in the chemical control of plant hormone responses

Chemical modulation of plant hormones has emerged as a powerful complement to genetic approaches. It enables the precise interrogation of complex and often redundant regulatory networks. Beyond their value for basic research, small-molecule tools offer reversible and tunable control of hormone responses, with growing relevance for sustainable agriculture. Although chemical regulators have been used since the earliest studies of plant hormones, recent methodological advances have substantially reshaped the field. Advances over the past 5 years in chemical optimization, target identification strategies, structural biology and artificial intelligence (AI)-assisted approaches have driven a field-wide shift. This shift favors highly specific, tunable ligands with defined protein targets. Along with a broad overview of small-molecule regulators, we integrate these discoveries across hormone classes and synthesize the emerging principles, challenges, and strategies in the chemical manipulation of plant hormones. We discuss how these advances are expanding both the scope and translational potential of these tools to support crops' performance under climate stress.