Mechanical stress induces anatomical changes, tomato early flowering, and increased yield involving ethylene and auxins

Plants have evolved mechanisms to perceive and face mechanical stress (MS) caused by physical forces, including compacted soils, winds, rain, pathogens, and interactions with animals and plants. Previous research indicated that applying mechanical treatment (MT) to Arabidopsis increases both xylem area and seed yield. To explore sustainable tomato production, we applied MT - combining stem bending, weighting, and particular touching - to 10-day-old seedlings, using a specific weight on the upper stem for 48 h. Two days after the treatment, we observed stem enlargement and increased the number of xylem vessels and area in MT plants. Additionally, we noticed earlier flowering, leading to increased tomato production. The transcriptome of MT-treated plants revealed significant changes in the expression of several essential genes involved in central metabolism, growth responses, and crucial phytohormone signalling. By studying different tomato mutants in the ethylene and auxin signalling pathways, we demonstrated that both hormones play essential roles in the plant responses to combined MT. Our findings suggest that combined MT generates a beneficial MS in tomato plants that induces plant morphoanatomical changes that promote early flowering and increased yield, providing a promising strategy for sustainable agriculture. Stems from tomato plants of the Ailsa Craig variety were used for the analysis. The samples were taken from plants subjected to a mechanical treatment, which consisted of the application of a wooden device at the apex of the stems, generating a determined weight for 48 hours. In addition, a group of control plants was included. Stem samples were collected 6 hours after the start of the treatment and 10 days after the end of the treatment.