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United States Department of Agriculture

Agricultural Research Service

Title: Molecular and SNP characterization of two genome specific transcription factor genes GhMyb8 and GhMyb10 in cotton species

Authors
item Hsu, Chuan-Yu - MISSISSIPPI STATE UNIV
item An, Chuanfu - MISSISSIPPI STATE UNIV
item Saha, Sukumar
item Ma, Din-Pow - MISSISSIPPI STATE UNIV
item Jenkins, Johnie
item Scheffler, Brian
item Stelly, David - TEXAS A&M UNIVERSITY

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 14, 2007
Publication Date: February 1, 2008
Citation: Hsu, C., An, C., Saha, S., Ma, D., Jenkins, J.N., Scheffler, B.E., Stelly, D. 2008. Molecular and SNP characterization of two genome specific transcription factor genes GhMyb8 and GhMyb10 in cotton species. Euphytica. 159:259-273.

Interpretive Summary: The Myb gene family generally serves as transcriptional factors and regulates the gene expression levels of many plant-specific processes, including secondary metabolism, cell shape development, cell division, signal transduction, trichome development, and disease resistance. Since cotton fibers are single-celled seed trichomes differentiating from the epidermal cells of cotton ovules, the role of Myb proteins in regulating the differentiation and development of fibers will help in understanding the genetic mechanism controlling fiber development. In this research, two members of Myb gene family alloallelic R2R3-Myb genes (GhMyb8 and GhMyb10) were isolated from a fiber cDNA library of allotetraploid (AD genome) cotton. The expression of GhMyb8/GhMyb10 transcript and its possible physiological role was characterized. The sequence variations of these two Myb genes among the selected cotton species were determined and SNP markers were developed for chromosomal assignment. Northern blot analysis showed that GhMyb8 and GhMyb10 are expressed in all examined tissues, including leaves, flowers, roots, and fibers from different developmental stages; however, the transcript level of GhMyb8/10 is more abundant in flowers and roots. The ectoptic expression of cotton GhMyb10 in transgenic tobacco plants showed the abnormal cell shapes in leaf trichomes, suggesting that GhMyb8 and GhMyb10 might play a role in the process of trichome cell differentiation. The results showed that the average rate of SNP per nucleotide among the selected genotypes in the two gene fragments was 3.75% (~ one SNP per 27 nucleotide). We could not detect chromosomal location of the SNP markers with the available aneuploid lines.

Technical Abstract: Two R2R3-Myb cDNAs (GhMyb8 and GhMyb10) and their corresponding genes were isolated and characterized from allotetraploid cotton (Gossypium hirsutum L. cv. DES119) fiber cells. Both GhMyb8 and GhMyb10 exhibit some conserved features shared in subgroup 4 of plant R2R3-MYB proteins, including the GIDxxH motif and a zinc-finger domain. Both genomic origin and single nucleotide polymorphism (SNP) analyses reveal that GhMyb8 and GhMyb10 are alloallelic genes in the allotetraploid cotton (AD genome). GhMyb10 is derived from the A2 subgenome, whereas GhMyb8 is from the D5 subgenome. Possible chromosomal locations of these two genes were explored by SNP marker based deletion analyses. The results showed that the average rate of SNP per nucleotide among the selected genotypes in the two gene fragments was 3.75% (~ one SNP per 27 nucleotide), and 0.55% and 5.14% in coding regions and 3’-UTR (3’ untranslated regions), respectively. Northern blot analysis showed that GhMyb8 and GhMyb10 are expressed in all examined tissues, including leaves, flowers, roots, and fibers from different developmental stages; however, the transcript level of GhMyb8/10 is more abundant in flowers and roots. Cotton fibers are single-celled seed trichomes differentiating from the epidermal cells of cotton ovules. The ectoptic expression of GhMyb10 in transgenic tobacco plants showed the abnormal cell shapes in leaf trichomes, suggesting that GhMyb8 and GhMyb10 might play a role in the process of trichome cell differentiation.

Last Modified: 7/23/2014
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