Early fruit development is critical for determining crop yield. Cell wall invertase (CWIN) and sugar transporters both play important roles in carbon allocation and plant development. However, there is little information about the relationship between CWIN and those functionally related sugar transporters during fruit development. By using transgenic tomato with an elevated CWIN activity, we investigated how an increase in CWIN activity may regulate the expression of sugar transporter genes during fruit development. Our analyses indicate that CWIN activity may be under tight regulation by multiple regulators, including two invertase inhibitors (INVINHs) and one defective CWIN (deCWIN) in tomato ovaries prior to anthesis. Among the sugar transporters, expression of SlSWEET12c for sucrose efflux and SlHT2 for hexose uptake was enhanced by the elevated CWIN activity at 10 and 15 days after anthesis of tomato fruit development, respectively. The findings show that some specific sugars will eventually be exported transporters (SWEETs) and hexose transporters (HTs) respond to elevate CWIN activity probably to promote rapid fruit expansion when sucrose efflux from phloem and hexose uptake by parenchyma cell are in high demand. The analyses provide new leads for improving crop yield by manipulating CWIN-responsive sugar transporters, together with CWIN itself, to enhance fruit development and sugar accumulation.

早期果实发育对于确定农作物产量至关重要。细胞壁转化酶（CWIN）和糖转运蛋白均在碳分配和植物发育中发挥重要作用。但是，关于果实发育过程中CWIN与功能相关的糖转运蛋白之间关系的信息很少。通过使用具有提高的CWIN活性的转基因番茄，我们研究了CWIN活性的增加如何在果实发育过程中调节糖转运蛋白基因的表达。我们的分析表明，花期前，番茄卵巢中的CWIN活性可能受到多种调控剂的严格调控，包括两种转化酶抑制剂（INVINHs）和一种缺陷的CWIN（deCWIN）。在糖转运蛋白中，SlSWEET12c 用于蔗糖外排和 抗体2番茄果实发育后第10天和15天时CWIN活性升高，从而增加了对己糖的吸收。研究结果表明，当从韧皮部排出蔗糖和薄壁组织细胞吸收己糖时，某些特定的糖最终将被出口转运蛋白（SWEETs）和己糖转运蛋白（HTs）对升高的CWIN活性作出响应，从而可能促进水果的快速膨胀。这些分析通过操纵CWIN响应性糖转运蛋白以及CWIN本身来提高果实发育和糖分积累，从而为提高作物产量提供了新的线索。