Biosynthesis and biological role of polyamine conjugates in flowers of Arabidopsis thaliana

多胺结合物被描述为许多植物物种的花成分。最近来自拟南芥的证据表明，这些缀合物的精确取代模式可能是花粉发育所需的，或者是花粉粒成熟和萌发所必需的。这些假设是基于一种新的绒毡层特异性，阳离子依赖性咖啡酰辅酶A O-甲基转移酶（CCoAOMT）样蛋白，AtTSM 1，参与拟南芥特定的苯丙多胺共轭物的装饰的鉴定。AtTSM 1-基因与几个花药特异性基因和相应的敲除系的酚分析模式的聚类表明，在这些缀合物的生物合成中至少有三个其他基因的关联。由此产生的酰胺被确定为拟南芥花粉可溶性部分的主要成分，它们在花粉超微结构或发育中起着目前未知的作用。本研究的目的是研究拟南芥和拟南芥科植物花和花粉中与该途径相关的基因和生物合成酶，确定其多胺的共轭模式，阐明这些普遍存在但尚不清楚的代谢产物在花粉粒成熟和成功结实中的生物学作用。

Polyamine conjugates are described as flower constituents of many plant species. Recent evidence from Arabidopsis suggests that the precise substitution pattern of these conjugates may be required for anther development or be essential for pollen grain maturation and germination. These assumptions are based on the identification of a novel tapetum-specific, cation-dependent caffeoyl coenzyme A O-methyltransferase (CCoAOMT)- like protein, AtTSM1, involved in the decoration of Arabidopsis specific phenylpropanoid polyamine conjugates. Clustering of the AtTSM1-gene with several anther specific genes and the phenolic profiling pattern of the corresponding knockout lines demonstrate the association of at least three other genes in the biosynthesis of these conjugates. The resulting amides were identified as the predominant constituents in the soluble portion of Arabidopsis pollen where they play a currently unknown role in pollen ultrastructure or development. With this proposal we aim to characterize the relevant genes and biosynthetic enzymes associated with this pathway, determine the polyamine conjugate pattern of Arabidopsis and related Brassicaceae in flowers and pollen, to clarify the biological role of these universal, yet poorly understood metabolites in pollen grain maturation and successful seed set.