Sturm A, Tang GQ
Friedrich Miescher Institute, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.
Trends Plant Sci. 1999 Oct;4(10):401-407. doi: 10.1016/s1360-1385(99)01470-3.
Sink organs of most plant species are supplied with carbon and energy in the form of sucrose. The channeling of sucrose into sink metabolism requires its cleavage by several isoforms of invertase and sucrose synthase, which are localized in different subcellular compartments. These activities regulate the entry of sucrose into distinct biochemical pathways, such as respiration or biosynthesis of cell wall polysaccharides and storage reserves. Other vital roles for the sucrose-cleaving enzymes include invertase activity at the site of phloem unloading and vacuolar invertase and sucrose synthase in sink organs, which drives the long-distance transport of sucrose. In addition, invertases have been implicated in the defense response and in turgor-driven cell expansion, and sucrose synthase expression is associated with low temperature and anaerobiosis responses. Finally, because sugars also regulate gene expression, the sucrose-cleaving enzymes play a fundamental role in controlling cell differentiation and development.
大多数植物物种的库器官以蔗糖的形式获得碳和能量。蔗糖进入库代谢需要通过几种定位于不同亚细胞区室的转化酶和蔗糖合酶同工型将其裂解。这些活性调节蔗糖进入不同生化途径，如呼吸作用或细胞壁多糖和贮藏物质的生物合成。蔗糖裂解酶的其他重要作用包括韧皮部卸载部位的转化酶活性以及库器官中的液泡转化酶和蔗糖合酶，它们驱动蔗糖的长距离运输。此外，转化酶还参与防御反应和膨压驱动的细胞扩展，蔗糖合酶的表达与低温和厌氧反应相关。最后，由于糖类也调节基因表达，蔗糖裂解酶在控制细胞分化和发育中起基本作用。
