A SNP of HD-ZIP I transcription factor leads to distortion of trichome morphology in cucumber (Cucumis sativus L.)

Leyu Zhang,Hui Du,Duo Lv,Keyan Zhang,Gang Wang,Jian Pan,Haifan Wen,Run Cai,Junsong Pan,Yue Chen,Huanle He

doi:10.1186/s12870-021-02955-1

Abstract

BackgroundTrichomes are excellent model systems for the analysis of cell differentiation and play essential roles in plant protection. From cucumber inbred line ‘WD1’, we identified an EMS-induced trichome abnormally developing mutant, nps, which exhibited smaller, denser and no pyramid-shaped head trichomes.ResultsUsing F2 and BC1 populations constructed from a cross between nps and ‘9930’, the genetic analysis showed that the nps trait is controlled by a single recessive nuclear gene. We identified CsNps by map-based cloning with 576 individuals of the F2 population generated from the cross of nps and inbred line ‘9930’. The CsNps was located at a 13.4-kb genomic region on chromosome 3, which region contains three predicted genes. Sequence analysis showed that only one single nucleotide mutation (C → T) between 9930 and nps was found in the second exon of Csa3G748220, a plant-specific class I HD-Zip gene. The result of allelism test also indicated that nps is a novel allelic mutant of Mict (Micro-trichome). Thus, nps was renamed mict-L130F. By comparing the transcriptome of mict-L130F vs WD1 and 06–2 (mict) vs 06–1 (wildtype, near-isogenic line of 06–2), several potential target genes that may be related to trichome development were identified.ConclusionsOur results demonstrate that Mict-L130F is involved in the morphogenesis of trichomes. Map-based cloning of the Mict-L130F gene could promote the study of trichome development in cucumber.

Highlights

Trichomes are large specialized epidermal cells distributed on aerial parts [1,2,3]
Phenotypic characterization Both the nps and Wild type (WT) are covered by trichomes on male flowers, tendrils, fruits and leaves
Compared with the WT trichomes, the nps trichomes appeared to be short and tender on leaves, female flowers, and tendrils or spines on fruit (Fig.1 a-d). 9930, which was used for producing the F2 population for map-based cloning, shows a similar phenotype to WT in leaves, stems, and other organs

Summary

Introduction

Trichomes are large specialized epidermal cells distributed on aerial parts [1,2,3]. The trichome can be classified as unicellular or multicellular, glandular or non-glandular, and branched or unbranched [4]. Trichomes play important roles in protecting plants from biotic and abiotic stresses, such as insect predation, excess transpiration and UV light [5, 6]. In Arabidopsis, as giant single epidermal cells, trichomes have become an excellent model system to study cell differentiation and development because it is easy to analyze them at the genetic, genomic and cell biology levels. Trichomes are excellent model systems for the analysis of cell differentiation and play essential roles in plant protection. From cucumber inbred line ‘WD1’, we identified an EMS-induced trichome abnormally developing mutant, nps, which exhibited smaller, denser and no pyramid-shaped head trichomes

Methods

Results

Discussion

Conclusion