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的花成分。来自拟南芥的最新证据表明，这些偶联物的精确替代模式可能是花药发育所必需的，也可能是花粉粒成熟和萌发所必需的。这些假设是基于鉴定了一种新的绒毛膜特异的、阳离子依赖的咖啡酰辅酶A O-甲基转移酶(CCoAOMT)样蛋白AtTSM1，它参与了拟南芥特异的苯丙素多胺结合物的修饰。AtTSM1基因与几个花药特异基因的聚类以及相应基因敲除系的酚类图谱表明，至少有三个其他基因与这些连接物的生物合成有关。由此得到的酰胺类化合物被鉴定为拟南芥花粉可溶部分的主要成分，它们在花粉超微结构或发育中的作用目前尚不清楚。根据这一建议，我们的目标是确定与这一途径相关的基因和生物合成酶的特征，确定拟南芥和相关十字花科植物在花和花粉中的多胺结合模式，以阐明这些普遍存在的、但知之甚少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.