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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Crop Germplasm Research » Research » Publications at this Location » Publication #319645

Research Project: Developing Genomic and Genetic Tools for Exploiting Cotton Genetic Variation

Location: Crop Germplasm Research

Title: Fine mapping and candidate gene analysis of the dominant glandless gene Gl^e2 in cotton (Gossypium spp.)

Author
item CHENG, HAILIANG - Chinese Academy Of Agricultural Sciences
item LU, CUIRUI - Chinese Academy Of Agricultural Sciences
item Yu, John
item ZOU, CHANGSONG - Chinese Academy Of Agricultural Sciences
item ZHANG, YOUPING - Chinese Academy Of Agricultural Sciences
item WANG, QIAOLIAN - Chinese Academy Of Agricultural Sciences
item HUANG, JUAN - Chinese Academy Of Agricultural Sciences
item FENG, XIAOXU - Chinese Academy Of Agricultural Sciences
item JIANG, PENGFEI - Chinese Academy Of Agricultural Sciences
item YANG, WENCUI - Chinese Academy Of Agricultural Sciences
item SONG, GUOLI - Chinese Academy Of Agricultural Sciences

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2016
Publication Date: 8/1/2016
Citation: Cheng, H., Lu, C., Yu, J., Zou, C., Zhang, Y., Wang, Q., Huang, J., Feng, X., Jiang, P., Yang, W., Song, G. 2016. Fine mapping and candidate gene analysis of the dominant glandless gene Gl^e2 in cotton (Gossypium spp.). Theoretical and Applied Genetics. 129:1347-1355.

Interpretive Summary: Cotton not only produces the leading natural fiber for the textile industry, it is also an excellent source of oil and protein for humans and animals. However, utilizing this nutrition source is greatly limited by toxic gossypol in pigment glands. Here we cloned an incomplete dominant gene (Gl2e) in polyploid cotton and demonstrated that this gene encodes a family member of MYC transcription factor with 475 amino acids. We named this MYC gene GhMYC1 which serves as a vital positive regulator in the organogenesis pathway of pigment glands. A single mutation of one nucleotide change to the bHLH-MYC transcription factor results in a glandless phenotype. Low expression of this gene does not produce pigment glands in cotton. This report is the first example of map-based gene cloning in cotton with functional validation. The results are of broad interest to the plant research community and they will facilitate the research on the glandless trait, MYC protein, and gossypol-free breeding in cotton.

Technical Abstract: Cottonseed product is an excellent source of oil and protein. However, this nutrition source is greatly limited in utilization by the toxic gossypol in pigment glands. It is reported that the Gl2e gene could effectively control the formation of the pigment glands. Here, three F2 populations were constructed for fine mapping of Gl2e using two pairs of near-isogenic lines (NILs) of Upland cotton differing almost only in the gland trait. DNA markers were identified from recently developed cotton genome sequence. The Gl2e gene was located within a 15 kb fragment between two markers CS2 and CS4 on chromosome 12. Based on the annotation database of cotton genome sequence, only one gene was identified in the fragment which encodes a family member of MYC transcription factor with 475-amino acids. One single nucleotide change (SNP) causes non-synonymous mutation (Ala/Val), located at the N-terminal region (pfam14215) of the transcription factor. We name this MYC gene GhMYC1 which expresses in four glanded plants while almost does not express in six glandless plants. Nullification of the GhMYC1 by virus-induced gene silencing (VIGS) in cotton significantly eliminated the pigment gland formation. Suppression of the gene expression was also found in the VIGS plants. Therefore, we conclude that GhMYC1 serves as a vital positive regulator in the organogenesis pathway of pigment gland, and low expression of this gene will not launch the downstream pathway responsible for the pigment gland formation. This finding will facilitate the research on glandless trait, cotton MYC proteins and low-gossypol cotton breeding.