Genome-wide cloning, identification, classification and functional analysis of cotton heat shock transcription factors in cotton (Gossypium hirsutum).
BACKGROUND
Heat shock transcriptional factors (Hsfs) play important roles in the processes of biotic and abiotic stresses as well as in plant development. Cotton (Gossypium hirsutum, 2n=4x=(AD)2=52) is an important crop for natural fiber production. Due to continuous high temperature and intermittent drought, heat stress is becoming a handicap to improve cotton yield and lint quality. Recently, the related wild diploid species Gossypium raimondii genome (2n=2x=(D5)2=26) has been fully sequenced. In order to analyze the functions of different Hsfs at the genome-wide level, detailed characterization and analysis of the Hsf gene family in G. hirsutum is indispensable.


RESULTS
EST assembly and genome-wide analyses were applied to clone and identify heat shock transcription factor (Hsf) genes in Upland cotton (GhHsf). Forty GhHsf genes were cloned, identified and classified into three main classes (A, B and C) according to the characteristics of their domains. Analysis of gene duplications showed that GhHsfs have occurred more frequently than reported in plant genomes such as Arabidopsis and Populus. Quantitative real-time PCR (qRT-PCR) showed that all GhHsf transcripts are expressed in most cotton plant tissues including roots, stems, leaves and developing fibers, and abundantly in developing ovules. Three expression patterns were confirmed in GhHsfs when cotton plants were exposed to high temperature for 1 h. GhHsf39 exhibited the most immediate response to heat shock. Comparative analysis of Hsfs expression differences between the wild-type and fiberless mutant suggested that Hsfs are involved in fiber development.


CONCLUSIONS
Comparative genome analysis showed that Upland cotton D-subgenome contains 40 Hsf members, and that the whole genome of Upland cotton contains more than 80 Hsf genes due to genome duplication. The expression patterns in different tissues in response to heat shock showed that GhHsfs are important for heat stress as well as fiber development. These results provide an improved understanding of the roles of the Hsf gene family during stress responses and fiber development.
Jun
J
Wang
Na
N
Sun
Ting
T
Deng
Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. zhangld@sjtu.edu.cn.
Lida
L
Zhang
Kaijing
K
Zuo
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000145:classification* / Q000235:genetics*; D004171:Diploidy; D005091:Exons / Q000235:genetics; D020440:Gene Duplication; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018745:Genome, Plant; D003368:Gossypium / Q000235:genetics*; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response / Q000235:genetics; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics; D017434:Protein Structure, Tertiary; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000145:classification* / Q000235:genetics*
D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D010940:Plant Proteins; D014157:Transcription Factors