Genome-wide analysis of basic helix–loop–helix genes in Dendrobium catenatum and functional characterization of DcMYC2 in jasmonate-mediated immunity to Sclerotium delphinii

Abstract

Dendrobium catenatum, belonging to the Orchidaceae, is a precious Chinese herbal medicine. Sclerotium delphinii (P1) is a broad-spectrum fungal disease, which causes widespread loss in the near-wild cultivation of D. catenatum. Thus, resistance breeding of D. catenatum has become the key to solve this problem. The basic helix–loop–helix (bHLH) gene family is closely related to plant resistance to external stresses, but the related research in D. catenatum is not deep enough yet. Phylogenetic analysis showed that 108 DcbHLH genes could be divided into 23 subgroups. Promoter cis-acting elements revealed that DcbHLHs contain a large number of stress-related cis-acting elements. Transcriptome analysis of MeJA and P1 treatment manifested that exogenous MeJA can change the expression pattern of most bHLH genes, especially the IIIe subgroup, including inhibiting the expression of DcbHLH026 (MYC2a) and promoting the expression of DcbHLH027 (MYC2b). Subcellular localization indicated that they were located in the nucleus. Furthermore, exogenous MeJA treatment significantly delayed disease time and reduced lesion size after infection with P1. DcMYC2b-overexpression Arabidopsis lines showed significantly smaller lesions after being infected with P1 than the wild type, indicating that DcMYC2b functions as an important positive regulator in D. catenatum defense against P1. Our findings shed more insights into the critical role of the DcbHLH family in plants and the resistance breeding of D. catenatum.

Transcriptome-wide characterization of bHLH transcription factor genes in Lycoris radiata and functional analysis of their response to MeJA

“…JA is a critical defense signaling molecule regulating different biological processes. Previous study revealed that MeJA could regulate the expression of bHLH family genes ( Zander et al., 2020 ; Guo et al., 2021 ; Li et al., 2022 ). Recently, tomato bHLH gene SlJIG has been demonstrated to be induced by JA, and function in terpene biosynthesis and resistance to insects and fungus ( Cao et al., 2022 ).…”

Whole-Transcriptome Sequencing Reveals the Global Molecular Responses and NAC Transcription Factors Involved in Drought Stress in Dendrobium catenatum

“…Transcription factors have emerged as critical regulatory factors governing various aspects of plant growth, development, and response to abiotic stress. Several studies have focused on exploring transcription factor families in D. catenatum, including AP2/ERF, WOX, TCP, MYB, LBD, WRKY, HD-ZIP, MADS-box, and bHLH [40][41][42][43][44][45][46][47]. However, the characterization of the NAC transcription factor family in RJ remains unexplored.…”

Basic Helix-Loop-Helix Transcription Factors: Regulators for Plant Growth Development and Abiotic Stress Responses

“… Phylogenetic analysis of the species based on genome-wide association study of the basic helix-loop-helix (bHLH) family. The total number of bHLH transcription factors identified from the genome of each species are indicated [ 5 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. …”