Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Hainan Key Laboratory for Cultivation & Physiology of Tropical Crops, State Key Laboratory Incubation Base for Cultivation and Physiology of Tropical Crops, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
Int J Mol Sci. 2023 Aug 16;24(16):12857. doi: 10.3390/ijms241612857.
Brassinolide (BR) is an important plant hormone that regulates the growth and development of plants and the formation of yield. The yield and quality of latex from are regulated by phytohormones. The understanding of gene network regulation mechanism of latex formation in rubber trees is still very limited. In this research, the rubber tree variety CATAS73397 was selected to analyze the relationship between BR, water deficit resistance, and latex yield. The results showed that BR improves the vitality of rubber trees under water deficit by increasing the rate of photosynthesis, reducing the seepage of osmotic regulatory substances, increasing the synthesis of energy substances, and improving the antioxidant system. Furthermore, BR increased the yield and quality of latex by reducing the plugging index and elevating the lutoid bursting index without decreasing mercaptan, sucrose, and inorganic phosphorus. This was confirmed by an increased expression of genes related to latex flow. RNA-seq analysis further indicated that DEG encoded proteins were enriched in the MAPK signaling pathway, plant hormone signal transduction and sucrose metabolism. Phytohormone content displayed significant differences, in that trans-Zeatin, ethylene, salicylic acid, kinetin, and cytokinin were induced by BR, whereas auxin, abscisic acid, and gibberellin were not. In summary, the current research lays a foundation for comprehending the molecular mechanism of latex formation in rubber trees and explores the potential candidate genes involved in natural rubber biosynthesis to provide useful information for further research in relevant areas.
油菜素内酯（BR）是一种重要的植物激素，调节植物的生长发育和产量形成。植物激素调节橡胶树乳胶的产量和质量。橡胶树乳胶形成的基因网络调控机制的理解仍然非常有限。本研究选择橡胶树品种 CATAS73397 分析 BR、抗旱性和乳胶产量之间的关系。结果表明，BR 通过提高光合作用速率、减少渗透调节物质渗漏、增加能量物质合成和改善抗氧化系统，提高了干旱胁迫下橡胶树的活力。此外，BR 通过降低堵塞指数和提高类质体爆裂指数来增加乳胶的产量和质量，而不降低巯基、蔗糖和无机磷。这一点通过与乳胶流动相关的基因表达增加得到了证实。RNA-seq 分析进一步表明，DEG 编码的蛋白质在 MAPK 信号通路、植物激素信号转导和蔗糖代谢中富集。植物激素含量也存在显著差异，其中 BR 诱导了反式玉米素、乙烯、水杨酸、激动素和细胞分裂素的产生，而生长素、脱落酸和赤霉素则没有。综上所述，本研究为理解橡胶树乳胶形成的分子机制奠定了基础，并探索了参与天然橡胶生物合成的潜在候选基因，为相关领域的进一步研究提供了有用信息。
