Transcriptome and WGCNA analyses reveal NtRAP2-7 activates NtACOH1 expression to enhance low potassium tolerance in...

Potassium (K⁺) is the macronutrient that closely related to the growth and development of tobacco plant. The deprivation of K⁺ increases ethylene production. 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) is the key enzyme in the process of ethylene biosynthesis. To elucidate the relationship between ACO and low potassium (LK) stress, we overexpressed ACO homolog 1 (ACOH1) in tobacco plants. More results showed that overexpression of NtACOH1 in tobacco exhibited improved LK stress tolerance with increased proline, potassium and ACC content in the transgenic plants compared with wild type (WT). Meanwhile, NtACOH1-overexpression significantly decreased K⁺ efflux rate in transgenic tobacco roots under LK stress. KEGG analysis of transcriptome showed that the spliceosome, biosynthesis of amino acids and MAPK signaling pathway - plant were the three up-regulated pathways. The result of weighted gene co-expression network analysis exhibited that ethylene-responsive transcription factor RAP2-7, MYB transcription factor (MYBAS1), C2H2-13 protein might regulate the expression of NtACOH1. Further researches suggested NtRAP2-7 activated the expression level of NtACOH1 by yeast one-hybrid experiment and Dual-luciferase assays.Our results provide valuable candidate genes and enrich signal transduction network in tobacco in response to LK stress.