Advances in the Genetic Regulation of Soluble Solid Accumulation in Tomato Fruits

doi:10.13560/j.cnki.biotech.bull.1985.2025-1294

Abstract

Abstract:

Soluble solids constitute a key indicator for evaluating tomato (Solanum lycopersicum L.) fruit flavor quality, primarily comprising soluble sugars, organic acids, amino acids, and certain secondary metabolites. Notably, soluble sugar content plays a decisive role in determining fruit sweetness perception and processing quality. With the growing consumer demand for tomatoes that combine superior flavor profiles with nutritional value, enhancing soluble solids levels has become a critical research focus in modern tomato breeding and industrial upgrading. The accumulation of soluble solids in tomatoes involves a multi-level process encompassing photosynthetic product synthesis and supply, carbohydrate biosynthesis and metabolism, assimilate transport from “source” to “sink”, fruit internal sugar conversion and storage, transcriptional regulators, and environmental factors. Especially key genes such as LIN5, SWEET10, SlSUT1, and Brix9-2-5 and quantitative trait loci play crucial roles in regulating sugar content. The foundational pathways for soluble solids formation include carbohydrate synthesis, starch-sugar interconversion, sucrose hydrolysis, and hexose storage in vacuoles. Additionally, hormonal signals, transcriptional regulatory networks, source-reservoir relationships, and cultivation management practices further influence this complex process. This review systematically examines the chemical composition, metabolic pathways, transport mechanisms, transcriptional regulation, and major quantitative trait loci (QTLs) associated with soluble solids in tomatoes. It summarizes key strategies for high-sugar breeding and their molecular regulatory mechanisms, and constructs a comprehensive regulatory network model for tomato soluble solids. With the rapid advancement of multi-omics technologies, the study further outlines future research directions for tomato high-sugar breeding, aiming to provide theoretical foundations and scientific references for the targeted cultivation of high-quality tomatoes and the elucidation of mechanisms for fruit flavor quality improvement.

Key words: tomato, soluble solids, sugar metabolism, regulatory network, molecular breeding

CHENG Yun-xia, ZHANG Jun-hong, YE Jie. Advances in the Genetic Regulation of Soluble Solid Accumulation in Tomato Fruits[J]. Biotechnology Bulletin, 2026, 42(3): 145-155.

Figures/Tables 2

References 51

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基因类别 Gene category	代表基因 Representative gene	主要功能 Major function	与TSS的关系 Relationship to TSS	关键特点 Key features	参考文献 Reference
糖代谢基因 Glucose metabolism genes	SPS	蔗糖合成限速酶	增强叶片向果实的蔗糖输出	高糖材料中SPS活性更高；受光照和胁迫调控	［24］
	SuSy	蔗糖→UDP-葡萄糖+果糖	促进果实膨大；维持库活性	并非直接决定甜度，但影响糖流能力	［38］
	SlVI	水解蔗糖	敲除SlVI叶片增大；促进蔗糖含量积累	敲除SlVI会导致果实蔗糖含量增加，果实硬度增强	［18］
	INV（cwINV）/LIN5	水解蔗糖	决定糖积累的核心基因	LIN5自然变异可提高Brix；乙烯诱导；高糖育种核心靶标	［5］
糖转运基因 Sugar transporter gene	SlSUT1	蔗糖跨膜装载	SlSUT1抑制使糖含量下降	高糖材料中表达强；决定源装载能力	［25］
	SWEET10	蔗糖外排蛋白	SWEET10抑制降低Brix	与LIN5协同糖运输	［12］
	STP2	糖分转运蛋白	STP2提高阿拉伯糖水平	敲除STP2会降低CLV3阿拉伯糖基化水平	［39］
	TST3a	液泡膜糖转运蛋白	TST3a增加己糖转运活性	突变体材料提高番茄果实大小和糖含量	［40］
	LeHT1	葡萄糖/果糖吸收	影响六碳糖的吸收速率	高表达材料果实更甜；受乙烯与ABA调控	［41］
有机酸调控 Organic acid regulation	TMT	六碳糖向液泡转运	决定液泡储存糖能力	樱桃番茄中高表达常见	［42］
	ALMT9	液泡柠檬酸通道	减少柠檬酸，提高糖酸比	自然突变可改善风味	［29-30］
	PEPC	有机酸合成关键酶	影响糖酸平衡	与乙烯成熟过程耦合	［43］
	NAD-MDH	苹果酸代谢	调控酸含量	影响风味与TSS协同积累	［44］
调控糖积累的转录因子 Transcription factors regulating carbohydrate accumulation	MADS	调控成熟及糖代谢的基因	影响LIN5、SWEET等	成熟-代谢交叉调控核心	［9］
	NAC	果实膨大及后熟	上调HT、INV	调控库能力	［9］
	bZIP	糖信号调控	直接调控 SPS/SuSy	参与干旱提升糖度机制	［9］
	WRKY	逆境调控；ABA通路	调控SWEET、INV、HT	干旱诱导糖积累	［9］
	ERF	乙烯响应	调控LIN5、SWEET	成熟诱导糖代谢关键因子	［45］
源-库相关QTL Source-reservoir associated QTL	Brix9-2-5	调控果梗维管束数量	水分输入减少，同化物浓度上升	提高Brix	［10］
源-库相关QTL Source-reservoir associated QTL	fw2.2	控制果实大小	小果品种糖度更高	与库容量负相关	［46］

基因类别 Gene category	代表基因 Representative gene	主要功能 Major function	与TSS的关系 Relationship to TSS	关键特点 Key features	参考文献 Reference
糖代谢基因 Glucose metabolism genes	SPS	蔗糖合成限速酶	增强叶片向果实的蔗糖输出	高糖材料中SPS活性更高；受光照和胁迫调控	［24］
	SuSy	蔗糖→UDP-葡萄糖+果糖	促进果实膨大；维持库活性	并非直接决定甜度，但影响糖流能力	［38］
	SlVI	水解蔗糖	敲除SlVI叶片增大；促进蔗糖含量积累	敲除SlVI会导致果实蔗糖含量增加，果实硬度增强	［18］
	INV（cwINV）/LIN5	水解蔗糖	决定糖积累的核心基因	LIN5自然变异可提高Brix；乙烯诱导；高糖育种核心靶标	［5］
糖转运基因 Sugar transporter gene	SlSUT1	蔗糖跨膜装载	SlSUT1抑制使糖含量下降	高糖材料中表达强；决定源装载能力	［25］
	SWEET10	蔗糖外排蛋白	SWEET10抑制降低Brix	与LIN5协同糖运输	［12］
	STP2	糖分转运蛋白	STP2提高阿拉伯糖水平	敲除STP2会降低CLV3阿拉伯糖基化水平	［39］
	TST3a	液泡膜糖转运蛋白	TST3a增加己糖转运活性	突变体材料提高番茄果实大小和糖含量	［40］
	LeHT1	葡萄糖/果糖吸收	影响六碳糖的吸收速率	高表达材料果实更甜；受乙烯与ABA调控	［41］
有机酸调控 Organic acid regulation	TMT	六碳糖向液泡转运	决定液泡储存糖能力	樱桃番茄中高表达常见	［42］
	ALMT9	液泡柠檬酸通道	减少柠檬酸，提高糖酸比	自然突变可改善风味	［29-30］
	PEPC	有机酸合成关键酶	影响糖酸平衡	与乙烯成熟过程耦合	［43］
	NAD-MDH	苹果酸代谢	调控酸含量	影响风味与TSS协同积累	［44］
调控糖积累的转录因子 Transcription factors regulating carbohydrate accumulation	MADS	调控成熟及糖代谢的基因	影响LIN5、SWEET等	成熟-代谢交叉调控核心	［9］
	NAC	果实膨大及后熟	上调HT、INV	调控库能力	［9］
	bZIP	糖信号调控	直接调控 SPS/SuSy	参与干旱提升糖度机制	［9］
	WRKY	逆境调控；ABA通路	调控SWEET、INV、HT	干旱诱导糖积累	［9］
	ERF	乙烯响应	调控LIN5、SWEET	成熟诱导糖代谢关键因子	［45］
源-库相关QTL Source-reservoir associated QTL	Brix9-2-5	调控果梗维管束数量	水分输入减少，同化物浓度上升	提高Brix	［10］
源-库相关QTL Source-reservoir associated QTL	fw2.2	控制果实大小	小果品种糖度更高	与库容量负相关	［46］