Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, 571737, Hainan, People's Republic of China.
Planta. 2017 Nov;246(5):999-1018. doi: 10.1007/s00425-017-2739-z. Epub 2017 Jul 27.
43 HbPLCPs representing nine subfamilies or 20 orthologous groups were found in rubber, where paralogs were resulted from the recent WGD and local duplication. Several senescence-associated genes were also identified. Papain-like cysteine proteases (PLCPs) comprise a large family of proteolytic enzymes involved in plant growth and development, seed germination, organ senescence, immunity, and stress response. Despite their importance and the extensive research in the model plant Arabidopsis thaliana, little information is available on rubber tree (Hevea brasiliensis), a rubber-producing plant of the Euphorbiaceae family. This study performed a genome-wide identification of PLCP family genes in rubber, resulting in a relatively high number of 43 members. The phylogenetic analysis assigned these genes into nine subfamilies, i.e., RD21 (6), CEP (4), XCP (4), XBCP3 (2), THI (1), SAG12 (18), RD19 (4), ALP (2), and CTB (2). Most of them were shown to have orthologs in Arabidopsis; however, several members in SAG12, CEP and XBCP3 subfamilies form new groups as observed in other core eudicots such as Manihot esculenta, Ricinus communis, Populus trichocarpa, and Vitis vinifera. Based on an expert sequence comparison, 20 orthologous groups (OGs) were proposed for core eudicots, and rubber paralogs were shown to be resulted from the recent whole-genome duplication (WGD) as well as local duplication. Transcriptional profiling showed distinct expression pattern of different members across various tissues, e.g., root, leaf, bark, laticifer, flower, and seed. By using the senescence-specific HbSAG12H1 as the indicator, the transcriptome of senescent rubber leaves was deeply sequenced and several senescence-associated PLCP genes were identified. Results obtained from this study provide valuable information for future functional analysis and utilization of PLCP genes in Hevea and other species.
43 个 HbPLCP 代表 9 个亚科或 20 个直系同源群，在橡胶中被发现，其中旁系同源物是由最近的 WGD 和局部重复产生的。还鉴定了几个与衰老相关的基因。木瓜蛋白酶样半胱氨酸蛋白酶 (PLCP) 是一个庞大的酶家族，参与植物生长和发育、种子萌发、器官衰老、免疫和应激反应。尽管它们很重要，并且在模式植物拟南芥中进行了广泛的研究，但关于产胶植物巴西橡胶树（Hevea brasiliensis）的信息却很少。本研究在橡胶中进行了 PLCP 家族基因的全基因组鉴定，得到了相对较高数量的 43 个成员。系统发育分析将这些基因分为 9 个亚科，即 RD21（6）、CEP（4）、XCP（4）、XBCP3（2）、THI（1）、SAG12（18）、RD19（4）、ALP（2）和 CTB（2）。它们中的大多数在拟南芥中都有直系同源物；然而，在 SAG12、CEP 和 XBCP3 亚科中，几个成员形成了新的群体，就像在其他核心真双子叶植物如 Manihot esculenta、Ricinus communis、Populus trichocarpa 和 Vitis vinifera 中观察到的那样。基于专家序列比较，提出了核心真双子叶植物的 20 个直系同源群，并且橡胶旁系同源物是由最近的全基因组复制（WGD）以及局部复制产生的。转录谱分析显示不同成员在不同组织中的表达模式明显不同，例如根、叶、树皮、乳汁管、花和种子。使用衰老特异性的 HbSAG12H1 作为指示剂，对衰老橡胶叶片的转录组进行了深度测序，并鉴定了几个与衰老相关的 PLCP 基因。本研究的结果为未来在巴西橡胶树和其他物种中对 PLCP 基因的功能分析和利用提供了有价值的信息。
