HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis ( para rubber tree)
HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis ( para rubber tree)
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DOI：
10.1111/nph.13257
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发表时间：
2015-04-01
期刊：
影响因子：
9.4
通讯作者：
Tang, Chaorong
中科院分区：
文献类型：
--
作者：
Liu, Shujin;Lan, Jixian;Tang, Chaorong
在巴西橡胶树中，碱性/中性转化酶（A/N-Inv）负责胶乳（基本上是产橡胶乳管的细胞质，天然橡胶的来源）中的蔗糖催化，并与橡胶产量有关。然而，编码这种酶的基因及其分子和生物化学特性都没有得到很好的证明。三个橡胶树A/N-Inv基因，即HbNIN 1，2和3，首次在植物和大肠杆菌中克隆和表征。探测HbNIN 2 mRNA和蛋白的细胞定位。从胶乳中分离、纯化、鉴定了具有活性的A/N-Inv蛋白，并对其酶学性质进行了研究，根据HbNIN 2在大肠杆菌中的功能、在胶乳中的优势表达、其mRNA和蛋白在乳管中的明显定位以及其表达与橡胶产量的相关性，确定HbNIN 2是胶乳中主要的A/N-Inv基因。活性A/N-Inv蛋白从胶乳中部分纯化，并确定为HbNIN 2。吡哆醛对HbNIN 2酶活性的增强是其他植物中A/N-Invs所特有的。我们得出结论，HbNIN 2，胞质A/N-Inv，是负责蔗糖catenorization在橡胶乳管。研究结果对植物蔗糖催化剂的研究，特别是天然橡胶合成的研究具有一定的参考价值。
In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties.HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E.coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular.