Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs/State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs/State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, 570228, China.
Plant Physiol Biochem. 2023 Dec;205:108156. doi: 10.1016/j.plaphy.2023.108156. Epub 2023 Nov 7.
Tapping panel dryness (TPD) results in a severe reduction in latex yield in Hevea brasiliensis. However, the molecular regulatory mechanisms of TPD occurrence are still largely unclear. In this study, whole-transcriptome sequencing was carried out on latex from TPD and healthy trees. In total, 7078 long noncoding RNAs (lncRNAs), 3077 circular RNAs (circRNAs), 4956 miRNAs, and 25041 mRNAs were identified in latex, among which 435 lncRNAs, 68 circRNAs, 320 miRNAs, and 1574 mRNAs were differentially expressed in the latex of TPD trees. GO and KEGG analyses indicated that plant hormone signal transduction, MAPK signaling pathway, and ubiquitin-mediated proteolysis were the key pathways associated with TPD onset. Phytohormone profiling revealed significant changes in the contents of 28 hormonal compounds, among which ACC, ABA, IAA, GA, and JA contents were increased, while SA content was reduced in TPD latex, suggesting that hormone homeostasis is disrupted in TPD trees. Furthermore, we constructed a TPD-related competitive endogenous RNA (ceRNA) regulatory network of lncRNA/circRNA-miRNA-mRNA with 561 edges and 434 nodes (188 lncRNAs, 5 circRNAs, 191 miRNAs, and 50 mRNAs) and identified two hub lncRNAs (MSTRG.11908.1 and MSTRG.8791.1) and four hub miRNAs (hbr-miR156, miR156-x, miRf10477-y, and novel-m0452-3p). Notably, the lncRNA-miR156/157-SPL module containing three hubs probably plays a crucial role in TPD onset. The expression of network hubs and the lncRNA-miR156/157-SPL module were further validated by qRT-PCR. Our results reveal the TPD-associated ceRNA regulatory network of lncRNA/circRNA-miRNA-mRNA in latex and lay a foundation for further investigation of molecular regulatory mechanisms for TPD onset in H. brasiliensis.
割胶导致巴西橡胶树胶乳产量严重下降。然而，割胶导致胶乳产量严重下降的分子调控机制在很大程度上仍不清楚。本研究对割胶和健康胶树胶乳进行了全转录组测序。共鉴定出胶乳中的 7078 个长链非编码 RNA（lncRNA）、3077 个环状 RNA（circRNA）、4956 个 miRNA 和 25041 个 mRNA，其中割胶胶乳中有 435 个 lncRNA、68 个 circRNA、320 个 miRNA 和 1574 个 mRNA 差异表达。GO 和 KEGG 分析表明，植物激素信号转导、MAPK 信号通路和泛素介导的蛋白水解是与割胶相关的关键途径。植物激素分析显示 28 种激素化合物的含量发生显著变化，其中 ACC、ABA、IAA、GA 和 JA 的含量增加，而 SA 的含量减少，表明割胶树的激素平衡被打破。此外，我们构建了一个割胶相关的 lncRNA/circRNA-miRNA-mRNA 竞争性内源性 RNA（ceRNA）调控网络，该网络含有 561 个边缘和 434 个节点（188 个 lncRNA、5 个 circRNA、191 个 miRNA 和 50 个 mRNA），并鉴定出两个关键 lncRNA（MSTRG.11908.1 和 MSTRG.8791.1）和四个关键 miRNA（hbr-miR156、miR156-x、miRf10477-y 和 novel-m0452-3p）。值得注意的是，包含三个关键节点的 lncRNA-miR156/157-SPL 模块可能在割胶的发生中起着关键作用。通过 qRT-PCR 进一步验证了网络节点和 lncRNA-miR156/157-SPL 模块的表达。本研究揭示了巴西橡胶树胶乳中 lncRNA/circRNA-miRNA-mRNA 的割胶相关 ceRNA 调控网络，为进一步研究巴西橡胶树割胶的分子调控机制奠定了基础。
