NaLRR-RK4 mediates MAPK signaling to enhance plant defense against Alternaria alternata in Nicotiana attenuata.

This study investigates the role of NaLRR-RK4 in plant defense against Alternaria alternata in Nicotiana attenuata, focusing on the differential gene expression in wild-type (WT, NaLRR-RK4 expressed) and NaLRR-RK4-silenced (RNAi) plants upon inoculation. Transcriptomic sequencing was conducted to analyze the expression of genes in WT and RNAi plants under Alternaria alternata infection and non-infection conditions, aiming to identify the pathways influenced by NaLRR-RK4 in conferring resistance to A. alternata. The activation of MAPK signaling in WT plants, including the upregulation of WRKY33, PR1, and ethylene- and ABA-responsive genes, plays a crucial role in enhancing resistance against A. alternata. In contrast, RNAi-treated plants exhibited reduced activation of these genes, highlighting the essential role of NaLRR-RK4 in initiating effective defense responses. NaLRR-RK4 functions as a key regulator of MAPK signaling, mediating plant defense against A. alternata through the coordinated activation of WRKY33, PR1, and ethylene- and ABA-responsive genes.