Biotechnology Bulletin ›› 2024, Vol. 40 ›› Issue (3): 155-169.doi: 10.13560/j.cnki.biotech.bull.1985.2023-1075

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Genome-wide Identification of the FAX family in Gossypium hirsutum and Functional Analysis of GhFAX1

YANG Wei-cheng(), SUN Yan, YANG Qian, WANG Zhuang-lin, MA Ju-hua, XUE Jin-ai(), LI Run-zhi()   

  1. Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu 030801
  • Received:2023-11-17 Online:2024-03-26 Published:2024-04-08
  • Contact: XUE Jin-ai, LI Run-zhi E-mail:yy15223068439@163.com;306214803@qq.com;rli2001@126.com

Abstract:

【Objective】 Fatty acid export(FAX)can mediate the transport of fatty acids from plant cells to the outer plastid, and play an important role in plant growth and development and response to abiotic stress. This work is to study the FAX family gene and function analysis of upland cotton(Gossypium hirsutum), and to provide new ideas for clarifying the molecular mechanism of oil accumulation and oil metabolism engineering of upland cotton. 【Method】 In order to reveal the potential function of the upland cotton FAX gene family, the GhFAX gene family was identified at the whole genome level, and the GhFAX1 protein was to have subcellular localization, and the function of GhFAX1 was verified by the genetic transformation of yeast and tobacco.【Result】 A total of 12 GhFAXs genes were identified in the genome of upland cotton, and all members of the family had similar gene structure and protein physicochemical properties. Sequence alignment analysis showed that only a few amino acids of GhFAX protein were highly conserved in evolution, suggesting their importance to function. Phylogenetic tree analysis showed that GhFAX gene was closely related to Asian cotton(Gossypium arboreum)and Raymond's cotton(G. raimondii). Transcriptome data suggested that GhFAXs may be involved in the regulation of upland cotton response to stress. Real-time fluorescence quantitative PCR showed that GhFAX4 was highly expressed in flowers, suggesting that GhFAX4 was involved in pollen development. The expression of GhFAX9 was high in the stems and GhFAX1 was high in all tissues of upland cotton. GhFAX1 was selected for subcellular localization analysis, and it was confirmed that GhFAX1 was localized in plastid. The GhFAX1 vector was constructed to overexpress GhFAX1 in Saccharobacteria cerevisiae. The results showed that the total fat of GhFAX1 overexpressed yeast was increased by 3.53%. Substrate bias experiments showed that GhFAX1 was selective to C16:0. GhFAX1 overexpressing tobacco was cultivated through genetic transformation of tobacco. The results showed that the chlorophyll of overexpressed tobacco increased by 13.24%, the fluorescence parameters NPQ increased by 14.17%, Fm increased by 34.94%, F0 decreased by 35.28%. The total fatty acids of the leaves and seeds increased by 5.2% and 6.52% respectively. The 1 000-grain weight of seeds increased by 19.1%. At the same time, the protein content decreased significantly.【Conclusion】 GhFAXs can increase the oil content of yeast and tobacco, participated in the transfer of palmitic acid from plastid, and causing the carbon source from protein synthesis pathway to oil synthesis pathway.

Key words: Gossypium hirsutum, fatty acid transport, genome identification, expression analysis, functional verification