A SNP Mutation in Homeodomain-DDT (HD-DDT) Transcription Factor Results in Multiple Trichomes (mt) in Cucumber (Cucumis sativus L.).

Zhige Yang,Mengfei Song,Jinfeng Chen,Qunfeng Lou,Marzieh Davoudi,Feng Cheng,Mengru Zhang

doi:10.3390/genes12101478

Zhige Yang, Mengfei Song + Show 5 more

Open Access

https://doi.org/10.3390/genes12101478

Copy DOI

Journal: Genes	Publication Date: Sep 23, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Nanjing Agricultural University

Abstract

Trichome is a natural physical barrier protecting plants against environmental stresses, natural infestations, ultraviolet rays and pathogenicity. Trichome also helps plants in maintaining appropriate water content by reducing transpiration rate. The molecular mechanism regulating unicellular trichome development in Arabidopsis has been extensively elucidated, but the molecular mechanism regulating multicellular trichome development remains unclear. In this study, we identified a multiple trichomes (mt) mutant from a cucumber EMS (Ethylmethylsulfone) mutagenesis population. Genetic analysis indicated that an incomplete dominant gene controls the mt trait. Using a combination of map-based cloning and BSA-seq (Bulked Segregant Analysis -Sequencing), we identified the candidate gene, CsaV3_6G050410, responsible for the mt mutation. Sequence alignment revealed one base substitution in gene CsaV3_6G050410, resulting in an amino acid substitution. The deduced amino acid sequence of CsaV3_6G050410 encodes a HD-DDT (homeodomain-DDT) transcriptional regulatory protein containing a conserved homeobox domain and a DDT domain. Gene expression analysis revealed that the expression level of CsaV3_6G050410 in the mt mutant was similar to that in the WT (wild type). Transcriptome analysis indicated that the mt gene may regulate the development of the epidermis by influencing plant hormone signaling pathways or participating in several transcription factor pathways. The results of this study are fundamental for a better understanding of the function of the HD-DDT transcription factor in the trichome development of cucumber.

Highlights

Trichome is a specialized structure, developed from plant epidermal cells, mainly distributed on the surface of aerial organs, including leaves, stems and flower organs [1]
Compared with the wild type (WT) cucumber, the mt mutant cucumber had a higher density of trichomes covering the surfaces of its leaf, stem, tendril, flower organ and ovary (Figure 1)
Scanning electron microscopy revealed that the number, size, arrangement and shape of trichomes on the mt leaf were significantly different from those in the wild type

Summary

Introduction

Trichome is a specialized structure, developed from plant epidermal cells, mainly distributed on the surface of aerial organs, including leaves, stems and flower organs [1]. Trichome initiation is controlled by the trimeric complex MBW (MYB-bHLH-WD repeat protein) [11,12]. Three genes encoding the R2R3-MYB, bHLH and WD repeat protein transcription factors, respectively, play positive regulatory roles in the development of trichome. There are numerous negative regulators of trichome development, such as CAPRICE (CPC), Triptychon (TRY), ENHANCER of TRY and CPCl (ETC1\ETC2) [16]. Mutation in these genes could increase the density and cluster frequency of trichome in Arabidopsis, indicating that these regulatory factors inhibit trichome development [17]. Compared with Arabidopsis, the regulation mechanisms of multicellular trichome development in other plants still remain unclear; only a few genes have been reported, such as hair and woolly in tomato [2,21]

Methods

Results

Conclusion