Characterization of Sugar Contents and Sucrose Metabolizing Enzymes in Developing Leaves of Hevea brasiliensis.
Characterization of Sugar Contents and Sucrose Metabolizing Enzymes in Developing Leaves of Hevea brasiliensis.
复制标题
巴西橡胶树发育叶中糖含量和蔗糖代谢酶的表征
DOI：
10.3389/fpls.2018.00058
复制
发表时间：
2018
影响因子：
5.6
通讯作者：
Tang C
中科院分区：
文献类型：
--
作者：
Zhu J;Qi J;Fang Y;Xiao X;Li J;Lan J;Tang C
迄今为止，植物叶子中的蔗糖代谢酶主要在温带植物中进行研究，很少与基因表达和糖分析同时进行。在这里，我们研究了巴西橡胶树（一种广泛种植的天然橡胶热带树种）叶子中的糖含量、基因表达和蔗糖代谢酶的活性。蔗糖、果糖和葡萄糖是橡胶叶在四个发育阶段（I 至 IV）中检测到的主要糖类，淀粉和白木糖醇为次要糖类。果糖和葡萄糖含量在第三阶段之前一直增加，但在第四阶段（成熟叶）急剧下降。另一方面，蔗糖在叶子发育过程中不断增加。所有蔗糖裂解酶的活性在成熟时均显着下降，这与大多数编码基因的转录下降一致。尽管蔗糖磷酸合酶（SPS）在成熟时转录水平较高，但其活性较低。因此，成熟叶中蔗糖含量高并不是由于蔗糖合成活性增加，而更多是由于蔗糖裂解能力下降。橡胶叶中蔗糖代谢酶的基因表达和活性与其他植物相比表现出显着差异。与大多数其他物种不同的是，在发育中的叶子中液泡转化酶在蔗糖裂解中占主导地位，细胞质转化酶和蔗糖合酶（裂解方向）在橡胶树中也占主导地位。虽然 SPS 通常负责植物叶子中的蔗糖合成，但蔗糖合酶（合成方向）与橡胶叶中的 SPS 相当或更高。成熟的橡胶叶具有异常高的蔗糖：淀粉比率，约为 11，是迄今为止报道的植物中最高的。
Sucrose-metabolizing enzymes in plant leaves have hitherto been investigated mainly in temperate plants, and rarely conducted in tandem with gene expression and sugar analysis. Here, we investigated the sugar content, gene expression, and the activity of sucrose-metabolizing enzymes in the leaves of Hevea brasiliensis, a tropical tree widely cultivated for natural rubber. Sucrose, fructose and glucose were the major sugars detected in Hevea leaves at four developmental stages (I to IV), with starch and quebrachitol as minor saccharides. Fructose and glucose contents increased until stage III, but decreased strongly at stage IV (mature leaves). On the other hand, sucrose increased continuously throughout leaf development. Activities of all sucrose-cleaving enzymes decreased markedly at maturation, consistent with transcript decline for most of their encoding genes. Activity of sucrose phosphate synthase (SPS) was low in spite of its high transcript levels at maturation. Hence, the high sucrose content in mature leaves was not due to increased sucrose-synthesizing activity, but more to the decline in sucrose cleavage. Gene expression and activities of sucrose-metabolizing enzymes in Hevea leaves showed striking differences compared with other plants. Unlike in most other species where vacuolar invertase predominates in sucrose cleavage in developing leaves, cytoplasmic invertase and sucrose synthase (cleavage direction) also featured prominently in Hevea. Whereas SPS is normally responsible for sucrose synthesis in plant leaves, sucrose synthase (synthesis direction) was comparable or higher than that of SPS in Hevea leaves. Mature Hevea leaves had an unusually high sucrose:starch ratio of about 11, the highest reported to date in plants.
登录
查看更多内容
影响因子：
7.4
作者：
HUBER, SC
通讯作者：
HUBER, SC
影响因子：
2.4
作者：
Belanger, G;McQueen, RE
通讯作者：
McQueen, RE
影响因子：
9.4
作者：
Liu, Shujin;Lan, Jixian;Tang, Chaorong
通讯作者：
Tang, Chaorong
影响因子：
3.1
作者：
Diaz, Martina;Gonzalez, Andres;Rossini, Carmen
通讯作者：
Rossini, Carmen
影响因子：
5.2
作者：
GUPTA, AK;MANN, P;SINGH, R
通讯作者：
SINGH, R