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Title: Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium

The majority of commercial cotton varieties planted worldwide are derived from Gossypium hirsutum, which is a naturally occurring allotetraploid produced by interspecific hybridization of A- and D-genome diploid progenitor species. While most cotton species are adapted to warm, semi-arid tropical and subtropical regions, and thus perform well in these geographical areas, cotton seedlings are sensitive to cold temperature, which can significantly reduce crop yields. One of the common biochemical responses of plants to cold temperatures is an increase in omega-3 fatty acids, which protects cellular function by maintaining membrane integrity. The purpose of our study was to identify and characterize the omega-3 fatty acid desaturase (FAD) gene family in G. hirsutum, with an emphasis on identifying omega-3 FADs involved in cold temperature adaptation. Results: Eleven omega-3 FAD genes were identified in G. hirsutum, and characterization of the gene family in extant A and D diploid species (G. herbaceum and G. raimondii, respectively) allowed for unambiguous genome assignment of all homoeologs in tetraploid G. hirsutum. The omega-3 FAD family of cotton includes five distinct genes, two of which encode endoplasmic reticulum-type enzymes (FAD3-1 and FAD3-2) and three that encode chloroplast-type enzymes (FAD7/8-1, FAD7/8-2, and FAD7/8-3). The FAD3-2 gene was duplicated inmore » the A genome progenitor species after the evolutionary split from the D progenitor, but before the interspecific hybridization event that gave rise to modern tetraploid cotton. RNA-seq analysis revealed conserved, gene-specific expression patterns in various organs and cell types and semi-quantitative RT-PCR further revealed that FAD7/8-1 was specifically induced during cold temperature treatment of G. hirsutum seedlings. Conclusions: The omega-3 FAD gene family in cotton was characterized at the genome-wide level in three species, showing relatively ancient establishment of the gene family prior to the split of A and D diploid progenitor species. The FAD genes are differentially expressed in various organs and cell types, including fiber, and expression of the FAD7/8-1 gene was induced by cold temperature. These data define the genetic and functional genomic properties of this important gene family in cotton and provide a foundation for future efforts to improve cotton abiotic stress tolerance through molecular breeding approaches.« less
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [4] ;  [4] ;  [5] ;  [6] ;  [4] ;  [3] ;  [1]
  1. US Arid-Land Agricultural Research Center, Maricopa, AZ (United States)
  2. US Arid-Land Agricultural Research Center, Maricopa, AZ (United States); Univ. of North Texas, Denton, TX (United States)
  3. Cornell Univ., Ithaca, NY (United States)
  4. Brigham Young Univ., Provo, UT (United States)
  5. West Virginia Univ., Morgantown, WV (United States)
  6. Univ. of North Texas, Denton, TX (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
BMC Plant Biology
Additional Journal Information:
Journal Volume: 14; Journal Issue: 1; Journal ID: ISSN 1471-2229
BioMed Central
Research Org:
University of North Texas, Denton, TX (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES chilling tolerance; cotton; drought; fatty acid desaturase; Gossypium; linolenic acid; omega-3 fatty acid