Phytohormone ethylene mediates oligogalacturonic acid-induced growth inhibition in tomato etiolated seedlings

• Published in: Plant science (Limerick) Vol. 330; p. 111643
• Main Authors: Zhou, Leilei, Ma, Yingxuan, Zhong, Silin, Cao, Jiankang, Luo, Yunbo, Qu, Guiqin
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.05.2023
• Subjects: ACC synthetase; Ethylene biosynthesis; Ethylenes - metabolism; Gene Expression Regulation, Plant; K252a; Plant Growth Regulators - metabolism; Seedlings; SlMPK3; Solanum lycopersicum; Solanum lycopersicum - genetics; Tomato seedlings; ACC synthetase; Ethylene biosynthesis; Tomato seedlings; SlMPK3; K252a; Solanum lycopersicum
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2023.111643

Plant growth and immunity are tightly interconnected. Oligogalacturonic acids (OGs) are pectic fragments and have been well investigated in plant immunity as a damage-associated molecular pattern. However, little is known regarding how OGs affect plant growth. Here, we reveal that OGs inhibit the growth of intact etiolated seedling by using the horticultural crop tomato as a model. This inhibitory effect is partially suppressed by the action of ethylene biosynthesis inhibitors, or the gene silencing of SlACS2, an essential rate-limiting enzyme for ethylene biosynthesis, suggesting that SlACS2-mediated ethylene production promotes OG-induced growth inhibition. Furthermore, OGs treatment elevates the SlACS2 protein phosphorylation, and its decrease by the kinase inhibitor K252a partially rescue OG-induced growth inhibition, indicating that SlACS2 phosphorylation involves in OG-induced growth inhibition. Moreover, the mitogen-activated protein kinase SlMPK3 could be activated by OGs treatment and can directly phosphorylate SlACS2 in vitro, and the bimolecular fluorescence complementation combining with the yeast two-hybrid assay shows that SlMPK3 interacts with SlACS2, indicating that SlMPK3 may participate in modulating the OG-induced SlACS2 phosphorylation and growth inhibition. Our results reveal a regulatory mechanism at both the transcriptional and post-transcriptional levels by which OGs inhibit the growth of intact plant seedlings. •The immune elicitor OGs inhibit the growth of intact etiolated seedling.•SlACS2-mediated ethylene production promotes OG-induced growth inhibition.•SlACS2 can be phosphorylated by tomato mitogen-activated protein kinase SlMPK3.•OGs may participate in mediating the trade-offs between plant growth and immunity.