A predominant isoform of fructokinase, HbFRK2, is involved in Hevea brasiliensis (para rubber tree) latex yield and regeneration.
A predominant isoform of fructokinase, HbFRK2, is involved in Hevea brasiliensis (para rubber tree) latex yield and regeneration.
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DOI：
10.1016/j.plaphy.2021.02.039
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
Pingchang Fang;Xiangyu Long;Yongjun Fang;Hua Chen;Ma Yu
中科院分区：
文献类型：
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作者：
Pingchang Fang;Xiangyu Long;Yongjun Fang;Hua Chen;Ma Yu
果糖激酶 (FRK) 介导果糖磷酸化，以调节碳流及其向库组织的分配。在橡胶树基因组中的 5 个 HbFRK 中，分离并检查了在乳胶（乳胶细胞质）中高表达的 3 个（HbFRK1-3）。根据系统发育分析和细胞内定位实验，HbFRK2和HbFRK3极有可能在细胞质中表达，而HbFRK1则在质体中表达。作为乳管中的主要异构体，HbFRK2 的转录本最高，其次是 HbFRK3 和 HbFRK1。在酶功能方面，HbFRK2 也表现出对果糖的最高亲和力。为了研究 FRK 在乳胶产量和再生中的作用，通过两项实验干预，当树木的乳胶流出量增加时，检查了 HbFRK 的变化。在第一种方法中，在之前未进行割胶的树木上开始割胶，导致乳胶产量在稳定之前的初始阶段连续割胶而增加。在第二种方法中，通过使用基于乙烯的产量刺激剂乙烯利进行处理来刺激已经定期割胶的树木的乳胶产量。使用任一方法诱导乳胶产量增加，转录物中 HbFRK2 和 HbFRK3 的丰度都会增加。这一发展在 HbFRK2 中尤为明显，可能反映了糖酵解的加强，以满足碳通量和能量需求，以增加橡胶生物合成，以替代在增加的乳胶产量中损失的橡胶。因此，我们的结果表明 HbFRK2 在果糖分解代谢中发挥着关键作用，以促进商业开发的橡胶树的橡胶再生。
Fructokinase (FRK) mediates fructose phosphorylation to regulate the carbon flow and its assignment to sink tissues. Out of fiveHbFRKsin the genome of the rubber tree, three (HbFRK1-3) that were highly expressed in latex (cytoplasm of laticifers) were isolated and examined. According to phylogenetic analysis and intracellular location experiment, both HbFRK2 and HbFRK3 were highly possible to be expressed in cytosol, while HbFRK1 was in plastid. As the predominant isoform in laticifers,HbFRK2had the highest transcripts, followed byHbFRK3andHbFRK1. In enzymatic function, HbFRK2 also showed the highest affinity for fructose. To examine the roles of FRKs in latex yield and regeneration, changes in HbFRKs were examined when latex outflow from the trees were increased through two experimental interventions. In the first approach, tapping was initiated on previously untapped trees, resulting in latex yield increasing with consecutive tapping at the initial stage before it stabilized. In the second approach, latex yield from trees that were already in regular tapping was stimulated by treatment with the ethylene-based yield stimulant, ethephon. Using either method to induce an increase in latex yield, the abundance of HbFRK2 and HbFRK3 in transcripts, was increased. This development, which was especially marked in HbFRK2, may reflect a strengthening of glycolysis to meet the carbon flux and energy demands for increased rubber biosynthesis to replace rubber lost in the increased latex yield. Our results, therefore, suggest that HbFRK2 plays a critical role in fructose catabolism to facilitate rubber regeneration in the commercially exploited rubber tree.