BACKGROUND The sugar will eventually be exported transporter (SWEET) family is a novel type of membrane-embedded sugar transporter that contains seven transmembrane helices with two MtN3/saliva domains. The SWEET family plays crucial roles in multiple processes, including carbohydrate transportation, development, environmental adaptability and host-pathogen interactions. Although SWEET genes, especially those involved in response to biotic stresses, have been extensively characterized in many plants, they have not yet been studied in potato. OBJECTIVE The identification of StSWEET genes provides important candidates for further functional analysis and lays the foundation for the production of good quality and high yield potatoes through molecular breeding. METHODS In this study, StSWEET genes were identified using a genome-wide search method. A comprehensive analysis of StSWEET family through bioinformatics methods, such as phylogenetic tree, gene structure and promoter prediction analysis. The expression profiles of StSWEET genes in different potato tissues and under P. infestans attack and sugar stress were studied using quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS Phylogenetic analysis classified 33 StSWEET genes into four groups containing 12, 5, 12 and 4 genes. Furthermore, the gene structures and conserved motifs found that the StSWEET genes are very conservative during evolution. The chromosomal localization pattern showed that the distribution and density of the StSWEETs on 10 potato chromosomes were uneven and basically clustered. Predictive promoter analysis indicated that StSWEET proteins are associated with cell growth, development, secondary metabolism, and response to biotic and abiotic stresses. Finally, the expression patterns of the StSWEET genes in different tissues and the induction of P. infestans and the process of the sugar stress were investigated to obtain the tissue-specific and stress-responsive candidates. CONCLUSION This study systematically identifies the SWEET gene family in potato at the genome-wide level, providing important candidates for further functional analysis and contributing to a better understanding of the molecular basis of development and tolerance in potato.

中文翻译：

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马铃薯（Solanum tuberosum L.）StSWEET家族基因的全基因组鉴定和表达分析。

背景技术糖最终将被输出转运蛋白（SWEET）家族是一种新型的膜包埋糖转运蛋白，其包含七个具有两个MtN3 /唾液结构域的跨膜螺旋。SWEET家族在多个过程中起着至关重要的作用，包括碳水化合物的运输，发育，环境适应性和宿主与病原体的相互作用。尽管SWEET基因，特别是那些与生物胁迫反应有关的基因，已经在许多植物中得到了广泛表征，但尚未在马铃薯中进行研究。目的StSWEET基因的鉴定为进一步的功能分析提供了重要的依据，并为通过分子育种生产高质量和高产马铃薯奠定了基础。方法在本研究中，使用全基因组搜索方法鉴定了StSWEET基因。通过系统进化树，基因结构和启动子预测分析等生物信息学方法对StSWEET家族进行全面分析。利用定量实时聚合酶链反应（qRT-PCR）研究了StSWEET基因在马铃薯不同组织中以及在无性疟原虫侵袭和糖胁迫下的表达谱。结果系统发育分析将33个StSWEET基因分为4组，分别包含12、5、12和4个基因。此外，基因结构和保守基序发现StSWEET基因在进化过程中非常保守。染色体定位图表明，StSWEETs在10个马铃薯染色体上的分布和密度均不均匀，且基本成簇。预测性启动子分析表明StSWEET蛋白与细胞生长，发育，次生代谢，以及对生物和非生物胁迫的反应。最后，研究了StSWEET基因在不同组织中的表达模式，致病疫霉的诱导以及糖胁迫的过程，从而获得了组织特异性和应激反应候选物。结论本研究在全基因组水平上系统地鉴定了马铃薯中的SWEET基因家族，为进一步的功能分析提供了重要的候选者，并有助于更好地了解马铃薯发育和耐受性的分子基础。