Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
Hainan Academy of Tropical Agricultural Resource, CATAS, Haikou, 571101, China.
Sci Rep. 2019 Sep 3;9(1):12673. doi: 10.1038/s41598-019-48958-9.
MADS-box transcription factors possess many functions in plant reproduction and development. However, few MADS-box genes related to secondary metabolites regulation have been identified. In Hevea brasiliensis, natural rubber is a representative cis-polyisoprenoids in secondary metabolism which occurs in the rubber laticifer cells, the molecular regulation basis of natural rubber biosynthesis is not clear. Here, a total of 24 MADS-box genes including 4 type I MADS-box genes and 20 type II MADS-box genes were identified in the transcriptome of rubber tree latex. The phylogenetic analysis was performed to clarify the evolutionary relationships of all the 24 rubber tree MADS-box proteins with MADS-box transcription factors from Arabidopsis thaliana and Oryza sativa. Four type I MADS-box genes were subdivided into Mα (3 genes) and Mβ (1 gene). Twenty type II MADS-box genes were subclassified into MIKC* (8 genes) and MIKC (12 genes). Eight MADS-box genes (HblMADS3, 5, 6, 7, 9, 13, 23, 24) were predominant expression in laticifers. ABA up-regulated the expression of HblMADS9, and the expression of HblMADS3, HblMADS5, HblMADS24 were up-regulated by MeJA. The function of HblMADS24 was elucidated. HblMADS24 bound HbFPS1 promoter in yeast and HblMADS24 activated HbFPS1 promoter in tobacco plants. Moreover, we proposed that HblMADS24 is a transcription activator of HbFPS1 which taking part in natural rubber biosynthesis.
MADS 框转录因子在植物生殖和发育中具有多种功能。然而，很少有与次生代谢物调控相关的 MADS 框基因被鉴定出来。在巴西橡胶树中，天然橡胶是次生代谢物中顺式聚异戊二烯的代表，存在于橡胶乳管细胞中，天然橡胶生物合成的分子调控基础尚不清楚。本研究共鉴定出橡胶树乳管转录组中的 24 个 MADS 框基因，包括 4 个 I 型 MADS 框基因和 20 个 II 型 MADS 框基因。对所有 24 个橡胶树 MADS 框蛋白与拟南芥和水稻的 MADS 框转录因子进行了系统进化分析，以阐明它们的进化关系。4 个 I 型 MADS 框基因分为 Mα（3 个基因）和 Mβ（1 个基因）。20 个 II 型 MADS 框基因分为 MIKC*（8 个基因）和 MIKC（12 个基因）。8 个 MADS 框基因（HblMADS3、5、6、7、9、13、23、24）在乳管中表达量较高。ABA 上调 HblMADS9 的表达，MeJA 上调 HblMADS3、HblMADS5、HblMADS24 的表达。阐明了 HblMADS24 的功能。HblMADS24 在酵母中与 HbFPS1 启动子结合，在烟草植物中激活 HbFPS1 启动子。此外，我们提出 HblMADS24 是参与天然橡胶生物合成的 HbFPS1 的转录激活因子。
