GLABROUS (CmGL) encodes a HD-ZIP IV transcription factor playing roles in multicellular trichome initiation in melon

Authors: ZHU, HUAYU - Henan Agricultural University; SUN, XIAOFEN - Henan Agricultural University; ZHANG, QI - Shanghai Jiaotong University; SONG, PENGYAO - Henan Agricultural University; HU, QIANMEI - Henan Agricultural University; ZHANG, XIAOJING - Henan Agricultural University; LI, XIANG - Henan Agricultural University; HU, JIANBIN - Henan Agricultural University; PAN, JUNSONG - Shanghai Jiaotong University; SUN, SHOURU - Henan Agricultural University; Weng, Yiqun; YANG, LUMING - Henan Agricultural University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2017
Publication Date: 11/17/2017
Citation: Zhu, H., Sun, X., Zhang, Q., Song, P., Hu, Q., Zhang, X., Li, X., Hu, J., Pan, J., Sun, S., Weng, Y., Yang, L. 2018. GLABROUS (CmGL) encodes a HD-ZIP IV transcription factor playing roles in multicellular trichome initiation in melon. Theoretical and Applied Genetics. 131:569–579. https://doi.org/10.1007/s00122-017-3019-9.

Interpretive Summary: Trichomes are small hairs covering the aerial parts of plants that originate from the epidermal cells, which can protect plants against the damage by insects and pathogens. The regulatory pathway of unicellular trichomes has been well studied in the model plant Arabidopsis. Little is known about the genetic control and regulation of trichome development in melon (Cucumis melo L.) which has multicellular trichomes. In this study, we identified a melon mutant, cmgl, which showed completely glabrous on all aerial organs. A bulked segregant analysis was conducted to identify polymorphic markers for linkage analysis in a population with 256 F2 plants, which allowed to locate the cmgl locus in melon chromosome VIII. Next-generation sequencing-aided marker discovery and fine mapping in a large population with 1536 F2 plants narrowed the candidate gene region to 12 kb that harbored only one candidate gene for cmgl, which encoded a class IV homeodomain-associated leucine zipper transcription factor. Four SNPs in the coding region of the CmGL gene were identified between the two parental lines; a single base substitution from C to A resulted in a premature termination codon and a truncated protein in the cmgl. The SNP was converted into a dCAPS marker, which showed co-segregation in the F2 population and 564 melon accessions. Result of this study will be helpful for better understanding of genetic control of trichome development in melon and marker-assisted selection (MAS) in developing new cultivars.

Technical Abstract: Trichomes are small hairs covering the above-ground parts of plants that serve multiple functions in plant life such as protection against insects and pathogens. Little is known about the genetic control and regulation of trichome development in melon. In this study, we identified a melon mutant, cmgl, which showed completely glabrous on all aerial organs. Genetic mapping with 256 F2 plants allowed to locate the cmgl gene ocus in melon chromosome VIII. Next-generation sequencing-aided marker discovery and fine mapping in a large population with 1536 F2 plants narrowed the candidate gene to a 12 kb region that harbored only one candidate gene for cmgl, which encoded a class IV homeodomain-associated leucine zipper transcription factor. Four SNPs in the coding region of CmGL gene were identified between the two parental lines; a single base substitution from C to A resulted in a premature termination codon and a truncated protein in the cmgl. The SNP was converted into a dCAPS marker, which showed co-segregation in the F2 population and 564 melon accessions. Result of this study will be helpful for better understanding of genetic control of trichome development in melon and marker-assisted selection in developing new melon cultivars.