Sui Jinlei, Xiao Xiaohu, Yang Jianghua, Fan Yujie, Zhu Sirui, Zhu Jinheng, Zhou Binhui, Yu Feng, Tang Chaorong
Natural Rubber Cooperative Innovation Center of Hainan Province & Ministry of Education of PRC, Hainan University, Haikou 570228, China; Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Scientific Research Centre, Key Laboratory of Emergency and Trauma, Ministry of Education, Hainan Medical University, Haikou 571199, China.
Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
Plant Sci. 2023 Jan;326:111510. doi: 10.1016/j.plantsci.2022.111510. Epub 2022 Oct 28.
RAPID ALKALINIZATION FACTORs (RALFs), which are secreted peptides serving as extracellular signals transduced to the inside of the cell, interact with the receptor-like kinase FERONIA (FER) and participates in various biological pathways. Here, we identified 23 RALF and 2 FER genes in Hevea brasiliensis (para rubber tree), and characterized their expression patterns in different tissues, across the process of leaf development, and in response to the rubber yield-stimulating treatments of tapping and ethylene. Four Hevea latex (the cytoplasm of rubber-producing laticifers)-abundant RALF isoforms, HbRALF19, HbRALF3, HbRALF22, and HbRALF16 were listed with descending expression levels. Of the four HbRALFs, expressions of HbRALF3 were markedly regulated in an opposite way by the treatments of tapping (depression) and ethylene (stimulation). All of the four latex-abundant RALFs specifically interacted with the extracellular domain of HbFER1. Transgenic Arabidopsis plants overexpressing these HbRALFs displayed phenotypes similar to those reported for AtRALFs, such as shorter roots, smaller plant architecture, and delayed flowering. The application of HbRALF3 and HbRALF19 recombinant proteins significantly reduced the pH of Hevea latex, an important factor regulating latex metabolism. An in vitro rubber biosynthesis assay in a mixture of latex cytosol (C-serum) revealed a positive role of HbFER1 in rubber biosynthesis. Taken together, these data provide evidence for the participation of the HbRALF-FER module in rubber production.
快速碱化因子（RALFs）是作为细胞外信号转导至细胞内部的分泌肽，与类受体激酶FERONIA（FER）相互作用，并参与各种生物学途径。在此，我们在巴西橡胶树（橡胶树）中鉴定出23个RALF基因和2个FER基因，并对它们在不同组织、叶片发育过程以及对割胶和乙烯刺激产胶处理的响应中的表达模式进行了表征。列出了四个巴西橡胶树胶乳（产胶乳管细胞的细胞质）中丰富的RALF异构体，即HbRALF19、HbRALF3、HbRALF22和HbRALF16，其表达水平呈递减顺序。在这四个HbRALFs中，HbRALF3的表达在割胶（抑制）和乙烯（刺激）处理下受到明显相反的调节。所有四个胶乳丰富的RALFs都与HbFER1的细胞外结构域特异性相互作用。过表达这些HbRALFs的转基因拟南芥植物表现出与报道的AtRALFs相似的表型，如根较短、植株结构较小和开花延迟。HbRALF3和HbRALF19重组蛋白的应用显著降低了巴西橡胶树胶乳的pH值，这是调节胶乳代谢的一个重要因素。在胶乳细胞质（C-血清）混合物中进行的体外橡胶生物合成试验揭示了HbFER1在橡胶生物合成中的积极作用。综上所述，这些数据为HbRALF-FER模块参与橡胶生产提供了证据。
