Comprehensive analysis of the 2R‐MYB family in Nicotiana tabacum and functional characterization of NtMYB35 in pigment metabolism

Abstract

AbstractMYB transcription factors (TFs) play important roles in plant growth and development, metabolic regulation, and stress responses. In the current study, 258 2R‐MYB TFs were identified in Nicotiana tabacum and systemically analyzed. The 2R‐NtMYB TFs were unevenly distributed on 23 chromosomes and were classified into 33 subgroups according to the Arabidopsis thaliana 2R‐MYB classification. The promoters of the 2R‐NtMYB harbor numerous potential cis‐acting elements involved in plant growth, metabolism, hormone signaling, and stress responsiveness. Chip‐based expression profiling of different tissues and growth stages revealed that the 2R‐NtMYBs showed constitutive or spatiotemporally specific expressions. RNA‐sequencing data indicated that some 2R‐NtMYBs, including NtMYB16, NtMYB27, NtMYB35, and NtMYB170, are involved in the response to one or several abiotic and biotic stresses, namely drought and resistance to black shank and bacterial wilt. Quantitative PCR results further revealed that NtMYBs respond to different hormones (abscisic acid, indole acetic acid, gibberellic acid, methyl jasmonate, and salicylic acid) and confirmed their involvement in abiotic stress responses like heat, drought, and salt. NtMYB35 overexpression and mutant lines generated using CRISPR‐Cas9 gene editing were used to verify the important role of NtMYB35 in regulating tobacco growth, pigment metabolism, and aphid resistance. These results provide a detailed overview of this TF family in N. tabacum and valuable insights for future functional analyses of NtMYB TFs.