Patterns of expansion and expression divergence in the plant polygalacturonase gene family
Patterns of expansion and expression divergence in the plant polygalacturonase gene family
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DOI：
10.1186/gb-2006-7-9r87
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发表时间：
2006-01-01
期刊：
影响因子：
12.3
通讯作者：
Patterson, Sara E.
中科院分区：
文献类型：
--
作者：
Kim, Joonyup;Shiu, Shin-Han;Patterson, Sara E.
背景：多聚半乳糖醛酸酶(PGs)是植物中的一个大基因家族，参与多种细胞分离过程。PG活性与植物的一系列发育过程有关，如种子萌发、器官脱落、角果和花药开裂、花粉粒成熟、果实软化和腐烂、木质部细胞形成和花粉管生长，因此该基因家族的成员具有不同的作用。仔细观察拟南芥和水稻PG之间的系统发育关系，并结合表达数据的分析，为解决关于重复基因的进化和功能的关键问题提供了机会。结果：我们发现串联和全基因组复制都对该基因家族的扩大做出了重要贡献，但与大量基因丢失有关。此外，在拟南芥和水稻的共同祖先中，至少有21个PG。我们还确定了拟南芥和水稻PGs之间的关系及其在拟南芥中的表达模式，以深入了解该基因家族成员之间的功能差异。通过对拟南芥五个组织和五个脱落阶段的表达分析，我们发现了大多数不同PG基因重叠但不同的表达模式。结论：表达数据表明每个PG基因成员都具有特定的功能或亚功能。来自全基因组复制的PG往往比来自串联复制的PG具有更相似的表达模式。我们的发现表明，PG复制经历了快速的表达差异，复制机制影响差异的速度。
Background: Polygalacturonases ( PGs) belong to a large gene family in plants and are believed to be responsible for various cell separation processes. PG activities have been shown to be associated with a wide range of plant developmental programs such as seed germination, organ abscission, pod and anther dehiscence, pollen grain maturation, fruit softening and decay, xylem cell formation, and pollen tube growth, thus illustrating divergent roles for members of this gene family. A close look at phylogenetic relationships among Arabidopsis and rice PGs accompanied by analysis of expression data provides an opportunity to address key questions on the evolution and functions of duplicate genes.Results: We found that both tandem and whole-genome duplications contribute significantly to the expansion of this gene family but are associated with substantial gene losses. In addition, there are at least 21 PGs in the common ancestor of Arabidopsis and rice. We have also determined the relationships between Arabidopsis and rice PGs and their expression patterns in Arabidopsis to provide insights into the functional divergence between members of this gene family. By evaluating expression in five Arabidopsis tissues and during five stages of abscission, we found overlapping but distinct expression patterns for most of the different PGs.Conclusion: Expression data suggest specialized roles or subfunctionalization for each PG gene member. PGs derived from whole genome duplication tend to have more similar expression patterns than those derived from tandem duplications. Our findings suggest that PG duplicates underwent rapid expression divergence and that the mechanisms of duplication affect the divergence rate.