巴西橡胶树死皮关键基因—翻译控制肿瘤蛋白特性及功能研究

Tapping panel dryness (TPD) is one of the most serious threats to the yield increase of natural rubber, and there are no effective measures to prevent and treat TPD in rubber tree. It was reported that TPD was a programmed cell death (PCD) process and the production and scavenging of reactive oxygen species, ubiquitin proteasome pathway, PCD and rubber biosynthesis were important pathways in TPD process. The translationally controlled tumor protein (TCTP) plays important biological roles, such as antioxidant and antiapoptotic activities, regulation of cell cycle, etc. The TCTPs in Hevea brasiliensis were highly conversed, associated with TPD and regulated by several stresses treatments in rubber tree. In addition, the TCTP proteins in rubber tree showed antiapoptotic roles in vitro. Based on the previous reports, we suggested that the TCTPs in rubber tree might play critical roles in key pathways involved in TPD process. In this project, the relationship between TCTP members with TPD, screening the proteins interacting with TCTPs, characterizations of TCTP proteins, biological roles and the functions involved in TPD process will be further analyzed. The results are helpful to not only further elucidate the molecular mechanisms involved in TPD, but also provide new insights into establishing effective and safe measures to prevent and treat TPD in Hevea brasiliensis.

橡胶树死皮是制约天然橡胶单产提高的首要因素，目前仍无有效措施防治死皮。前人研究表明橡胶树死皮是细胞程序化死亡过程，活性氧产生和清除、泛素蛋白酶体、细胞程序化死亡和橡胶生物合成为死皮发生重要调控途径。翻译控制肿瘤蛋白（translationally controlled tumor protein, TCTP)具有重要生物学功能，包括抗氧化、抗凋亡、调节细胞周期进程等。橡胶树TCTP成员在动植物间高度保守，表达与死皮相关且受多种逆境调控，蛋白具有抗氧化功能，推测橡胶树TCTP成员为死皮关键基因，在死皮发生重要调控途径中发挥关键作用。本项目拟从橡胶树TCTP成员入手，研究橡胶树TCTP成员与死皮的关系，筛选橡胶树TCTP成员的互作蛋白，分析橡胶树TCTP成员蛋白特性、生物学功能及在死皮发生中的作用。研究结果不仅有助于阐明死皮发生机制，也为制定安全、有效的橡胶树死皮防治措施提供理论指导。

死皮是制约天然橡胶单产提高的首要因素，活性氧代谢、泛素蛋白酶体、细胞程序化死亡和橡胶生物合成为死皮发生重要调控途径。翻译控制肿瘤蛋白(TCTP)具有抗氧化、抗凋亡等重要生物学功能，推测TCTP为死皮关键基因，在死皮发生中具有重要作用。.在克隆TCTP基因的基础上，分析基因表达模式及其与死皮的关系；筛选TCTP互作蛋白，分析其蛋白特性、生物学功能及其在死皮中的作用。橡胶树TCTP有两个成员，均有4个内含子和5个外显子。橡胶树TCTP基因非翻译区包含翻译调控元件，可调控TCTP蛋白翻译。橡胶树TCTP基因表达无组织特异性，在叶片不同发育时期表达存在显著变化。橡胶树TCTP基因在健康和死皮树及不同死皮发生率品种中存在表达差异，仅HbTCTP蛋白表达在死皮和健康树中存在差异。与启动子区含有逆境及激素相关调控元件一致，橡胶树TCTP基因表达受干旱、低温、伤害、乙烯和茉莉酸等处理调控。橡胶树TCTP属双子叶类TCTP蛋白，与麻风树TCTP蛋白聚为一类，三维结构与人TCTP蛋白高度一致，HbTCTP1具有钙结合活性；橡胶树TCTP蛋白在整个细胞中均有分布，具有抗氧化活性。HbTCTP1与两个REF和核糖体蛋白L44互作，HbTCTP与橡胶树REF、REF类逆境相关蛋白、小热激蛋白20和膜联蛋白互作。橡胶树TCTP基因在烟草中过表达均可抑制细胞死亡和活性氧产生，HbTCTP1促进愈伤组织分化，而HbTCTP抑制愈伤组织分化。.综上所述，橡胶树TCTP为多功能基因，在橡胶树生长发育、死皮、抗逆及激素反应等过程中发挥重要作用。作为死皮关键基因，推测其通过死皮重要调控途径—PCD，RB和ROS代谢中的抗凋亡和抗氧化反应调控橡胶树死皮。以上结果为进一步揭示死皮机制提供了新观点，为转基因技术降低橡胶树死皮发生率提供了候选基因，同时为制定有效死皮防治措施提供了理论指导。