The role of citrate synthase HbCS4 in latex regeneration of Hevea brasiliensis (para rubber tree)
The role of citrate synthase HbCS4 in latex regeneration of Hevea brasiliensis (para rubber tree)
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DOI：
10.1016/j.indcrop.2023.117637
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发表时间：
2023-12
影响因子：
5.9
通讯作者：
Yunxia Qin;Jianghua Yang;Zhiyong Wang;Yongjun Fang;Bin Hu;Xiaohu Xiao;Xiangyu Long
中科院分区：
文献类型：
--
作者：
Yunxia Qin;Jianghua Yang;Zhiyong Wang;Yongjun Fang;Bin Hu;Xiaohu Xiao;Xiangyu Long
巴西橡胶树是一种热带产橡胶作物，具有重要的经济价值，为全球橡胶工业提供了90%以上的天然橡胶。天然氮的生物合成属于乳管中典型的次生代谢。当然，天然橡胶的产生是一种巨大的能量代谢过程，尤其是在胶乳再生过程中。三羧酸(TCA)循环作为一次能源，有力地支持了乳管中天然橡胶的合成。本研究从橡胶树中分离到一个线粒体柠檬酸合成酶(CS)基因，命名为HbCS4，并比较了割胶和乙烯释放剂处理对其表达模式、酶活性和代谢产物的影响。对两个典型品种热研7-33-97和PR107以及HbCS4高表达品系也进行了分子分析。结果表明，热研7-33-97和PR107两个处理的HbCS4的表达特性或酶活性符合橡胶合成所需的能量需求和产量性状。此外，在HbCS4过表达的品系中，CS、NAD-IDH和α-KGDH三种关键酶的活性均同时升高。综上所述，这些结果表明，HbCS4是乳管供能所需的起始酶，它通过改变其表达或酶活性对橡胶生产有很大贡献。
The rubber tree,Hevea brasiliensis, is a tropical rubber-yielding crop with economic importance and provides over 90% of natural rubber (NR) for the global rubber industry. NR biosynthesis belongs to a typical secondary metabolism in laticifers. Definitely, NR production is a huge energy-consuming metabolism, especially during latex regeneration. The tricarboxylic acid (TCA) cycle, as the primary energy source, strongly supports NR synthesis in laticifers. In this study, a mitochondrial citrate synthase (CS) gene named asHbCS4was isolated from rubber tree and related changes of expression patterns, enzyme activity and metabolites assays in response to tapping and ethephon (ethylene-releasing agent) treatments were compared. These molecular analyses were also conducted in two typical varieties Reyan 7–33–97 and PR107 as well as inHbCS4-overexpressing lines. As a result, the expression characteristics ofHbCS4or its enzyme activity tallied with the energy requirement of rubber synthesis in both treatments and the yielding traits of varieties Reyan 7–33–97 and PR107. In addition, in HbCS4-overexpressing lines, the activities of three key enzymes in TCA cycle, namely CS, NAD-IDH and α-KGDH, were all increased simultaneously. To conclude, these results suggested that HbCS4 is the initial enzyme required for energy supply in laticifers, which greatly contributes to rubber production through changing its expression or enzyme activity.