Plant sucrose synthase (SUS) reversibly hydrolyzes sucrose, incorporating sucrose into different metabolic pathways. SUS1 homologous genes were characterized in 12 accessions of cultivated tomato Solanum lycopersicum and wild tomato species (Solanum section Lycopersicon). In total, 34 non-synonymous SNPs were found; among them, 17 caused radical amino acid substitutions, mostly in the wild species. The SUS1-based phylogenetic tree topology was represented by two clusters of red-fruited and green-fruited species, where S. pennellii and S. habrochaites showed the highest divergence. SUS1 transcription was detected in source and sink organs of one cultivated and four wild tomato species; it was the highest in buds and flowers, but lower in mature green fruit of the final size. In leaves and roots, the level of SUS1 expression corresponded to species evolutionary history, whereas no correlation was found between SUS1 levels and fruit size and sugar composition. Our findings suggest that SUS1-mediated reversible sucrose hydrolysis is important for maintaining the balance between sucrose and its monomers not only in fruits, but also in the other tomato organs.

中文翻译：

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番茄和野生番茄之间蔗糖合酶基因SUS1表达模式的差异

植物蔗糖合酶（SUS）可逆地水解蔗糖，将蔗糖整合到不同的代谢途径中。SUS1同源基因进行了表征在栽培番茄的12个种质番茄和野生型番茄物种（茄部番茄）。总共发现了34个非同义SNP。其中有17个引起自由基氨基酸取代，主要发生在野生物种中。基于SUS1的系统发育树拓扑结构由两个簇的红色水果和绿色水果组成，其中S. pennellii和S. habrochaites显示出最高的差异。SUS1在一种栽培和四种野生番茄物种的源和汇器官中检测到转录；在芽和花中它最高，而在最终大小的成熟绿色水果中则最低。在叶和根中，SUS1的表达水平与物种进化史相对应，而SUS1的水平与果实大小和糖成分之间没有相关性。我们的发现表明，SUS1介导的可逆蔗糖水解不仅对于维持水果中的蔗糖及其单体之间的平衡，而且对于其他番茄器官中的平衡均至关重要。