Uncovering missing enzymatic steps in biosynthesis of the plant biopolymer sporopollenin

高等植物的繁殖成功依赖于对可移动的雄配子体(花粉)的保护，使其免受生物和非生物胁迫，包括病原体、脱水、紫外线或变温。植物通过将花粉包裹在称为花粉壁的坚硬的外部屏障中来保护它们，花粉壁主要由复杂的生物聚合物孢粉蛋白组成。孢粉蛋白是高度惰性和耐降解性的，仍然是植物中关于其结构和组成方面了解最少的生物聚合物。然而，裸子植物花粉的最新研究进展提供了对孢粉蛋白聚合结构的第一次窥探，尽管相应的生物合成途径并不完全清楚。该项目的目标是通过描述被子植物拟南芥这一植物模式物种中的一系列候选基因，并通过分析相应的基因敲除系来研究它们的贡献，以填补目前关于孢粉蛋白生物合成方面的知识空白。通过共表达和转录组数据筛选出5个在孢粉合成中具有不同潜在意义的候选基因。他们提出的填补孢粉合成途径缺失步骤的作用将使用生化、分子、细胞和发育方法的组合进行评估。该项目将结合东道主机构在植物生物化学方面的专业知识与申请者在分子生物学、细胞生物学和遗传学方面的专业知识，提供多学科的方法来解决孢粉蛋白生物合成中的剩余问题。

Reproductive success of higher plants depends on protection of the mobile male gametophytes, the pollen, from exposure to biotic and abiotic stresses including pathogens, dehydration, UV light, or variable temperatures. Plants protect their pollen by encasing them in a tough external barrier called the pollen wall which is mainly composed of the complex biopolymer sporopollenin. Sporopollenin is highly inert and degradation-resistant, remaining the least understood biopolymer in the plants with regards to its structure and composition. Nevertheless, recent research advances in the case of gymnosperm pollen provide a first glimpse into the polymeric structure of sporopollenin even though the corresponding biosynthetic pathway is not entirely understood. The goal of this project is to fill the gaps in current knowledge of sporopollenin biosynthesis by characterizing a series of candidate genes in the angiosperm Arabidopsis thaliana, the plant model species, and investigating their contribution by analysis of the corresponding knockout lines. Five candidate genes encoding enzymes with different potential significance in sporopollenin biosynthesis were carefully selected by co-expression and transcriptome data. Their proposed role to fill in the missing steps of the sporopollenin biosynthesis pathway will be evaluated using the combination of biochemical-, molecular-, cell- and developmental approaches. This project will combine the host’s institutions expertise in plant biochemistry with the applicant’s expertise in molecular biology, cell biology and genetics providing the multidisciplinary approach to solve the remaining questions in the sporopollenin biosynthesis.