Abstract:

【Objective】To explore the involvement of SWEET（sugars will eventually be exported transporters）in sugar metabolism and response to abiotic stress in Camellia oleifera.【Method】Bioinformatics methods were used to analyze the gene structure, protein motif, chromosome localization, collinearity, cis-acting elements of promoter region and upstream regulators in CoSWEETs family, and RT-qPCR was used to analyze the expression pattern of CoSWEETs in different periods, tissues and stress responses.【Result】Total 14 CoSWEET genes were identified in Camellia oleifera for the first time, they were localized on 10 chromosomes, and there were differences in intron-exon numbers between different members. With 1-2 MtN3 conserved domain, the 14 CoSWEETs were divided into four subgroups by phylogenetic tree, and there were similar gene structures and motif in the same subgroup. There were differences in number of introns and exons among different members. Based on the analysis of promoter cis-acting elements and upstream transcription factor predictions, multiple cis-elements related to development, plant hormones and environmental stresses were found in the promoter region, and their expressions were regulated by transcription factors, like ERF, DOF, BBR-BPC and MYB. RT-qPCR results showed that CoSWEETs highly expressed in the fruit and root, and the expression in the seeds was related to the developmental stages. Moreover, several genes responding to low-temperature, drought or salt stress, such as CoSWEET1, CoSWEET2 and CoSWEET17 were mined based the expression profile of CoSWEETs members under abiotic stresses of low temperature, drought and high salt.【Conclusion】The expression of CoSWEETs is regulated by various hormones and transcription factors, and plays a crucial role in the development of seeds and the response to stress in Camellia oleifera.

Key words: Camellia oleifera, SWEET, protein structure, expression pattern analysis, abiotic stress