Jasmonate activates a SlJAZ2/3-SlMYC3-like module regulating K uptake in tomato response to low K stress.

Potassium (K), an essential macronutrient, strongly influences myriad fundamental processes, while its deficiency inhibits plant growth. Jasmonic acid (JA) regulates plant growth; however, its role in plant growth inhibition under K deficiency remains nebulous. Herein, we determined that JA significantly inhibits low K tolerance and K uptake in tomato. Methyl jasmonate treatment induced the expression of SlMYC3-like under low K stress, which bound the promoters of the genes that encode KT/KUP/HAK-type transporter (SlHAK5) and voltage-gated K channel (SlLKT1) and inhibited their expression. Knockdown of SlMYC3-like enhanced low K stress tolerance and decreased JA responses, while its overexpression led to low K stress sensitivity and promoted jasmonate responses in tomato. In addition, jasmonate ZIM-domain transcriptional repressor 2/3 (SlJAZ2/3) interacted with SlMYC3-like; this interaction decreased DNA-binding activity of SlMYC3-like. SlMYC3-like promoted SlJAZ2/3 expression, forming a negative feedback circuit in JA signaling. Silencing SlJAZ2/3 increased plant susceptibility to low K stress. Our findings demonstrate the involvement of the JA-SlJAZ2/3-SlMYC3-like module in K uptake and plant growth in tomato under low K stress, providing novel insights into the regulation of plant growth and K uptake.