| Cotton is an important economic crop in the world, and provides most natural raw material for textile industry. Upland cotton is the major cultivar of cotton,and products more than 90% of the total cotton fiber of the world. However, most cotton cultivars are cultivated in arid and semi-arid areas. Natural disasters, such as drought, salinity, low temperature, Fusarium and Verticillium wilt, are seriously hindering of cotton yield and quality improvement. Breeding cotton varieties with high resistance is one of the main tasks of cotton breeding.Stresses, including biotic and abiotic stresses, are harmful factors to agricultural production. Therefore, how to eliminate or reduce damagement caused by stresses is the basic thinking of crop resistance studies. Plants recept stimulations outside, transfer signal, regulate genes expression and, ultimately, produce resistance. Genes expression regulation, including up- and down-regulated, at the coreposition of the pathway. The down-regulated of gene expression has two aspects, the reduction of proteins synthesis and selective degradation of some existent proteins.Zinc finger proteins are proteins which can combine with zinc ions and folds into a finger-like structure, is the largest members of the transcription factors in number. Zinc finger domain binding zinc ion mainly relies on cysteine and histidine. The arrangement of systeine and histidine determines the mode of zinc finger protein binding zinc ion. Zinc finger domain, can combine with DNA, RNA, protein and lipid and involved in all aspects of life process. In plants, some zinc finger proteins, including some plant-specific zinc finger proteins, involved in responses to biotic and abiotic stresses.In this study, we scaned the cotton EST database and got five contigs with complete ORF by alignment. Primers were designed, and five stress-response zinc finger protein genes were isolated from upland cotton (Gossypium hirsutum L. cv Jinmian 19). These ZFPs, which were named GhSAP1, GhZFP2, GhZFP3, GhBBX1 and GhRCHY1, belong to four different zinc finger protein subfamilies. GhSAP1, GhBBX1 and GhRCHYl type zinc finger were first identified from cotton. The cDNA length of these five ZFPs is 591 bp,1005 bp,1026 bp,848bp and 1106 bp, respectively. Each ZFP contained a single complete ORF predicted 543 bp,813 bp, 813 bp,717 bp and 948 bp, which encode proteins contain 180,270,270,238 and 315 amino acid residues with an isoelectric point and a calculated molecular mass 8.97/19.3 kD,7.69/28.7 kD,8.68/28.6 kD,4.99/26.2 kD and 6.06/36.0 kD respectively. GhSAP1 contains an A20 and an AN1 zinc finger domain. GhZFP2 and GhZFP3 each contain two C2H2 zinc finger domains. GhBBX1 contains two B-Box domains. GhRCHYl contains a CHY and a RING-H2 zinc finger domain.A PCR-based linkage map, which was composed of 138 BC1 individuals that were generated from the cross [(TM-1×Hai7124)×TM-1], was used to map ZFPs on cotton chromosomes. GhSAP1, GhZFP2, GhZFP3, GhBBX1 and GhRCHY1 can be mapped to cotton chromosomes 8,5,19,23 and 18. Expression of ZFP genes in various cotton tissues by Q-PCR assay revealed that these ZFPs were lowest expressed in 5 DPA ovules while GhZFP2 and GhZFP3 were highest expression in root, and expression of the other three genes in roots, stems and leaves has no significant difference. Real-time Fluorescence Q-PCR was used to detect the expression of GhZFP genes under abiotic and biotic stresses. Compare with control, GhRCHY1 was induced by drought strongly, while GhSAP1 was dominantly induced by NaC1 and ABA, GhZFP3 was induced significantly by low temperature, GhZFP2 was induced strongly by verticillium wilt pathogen. These results indicate that the five zinc finger proteins play a role in stress respone in cotton. Further function studies of these ZFPs are under way. |
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