Mechanistic insights into the evolution of DUF26-containing proteins in land plants

First author: Donald R. Zak; Affiliations: University of Helsinki (赫尔辛基大学): Helsinki, Finland

Corresponding author: Michael Wrzaczek

Large protein families are a prominent feature of plant genomes and their size variation is a key element for adaptation. However, gene and genome duplications pose difficulties for functional characterization and translational research. Here we infer the evolutionary history of the DOMAIN OF UNKNOWN FUNCTION (DUF) 26-containing proteins. The DUF26 emerged in secreted proteins. Domain duplications and rearrangements led to the appearance of CYSTEINE-RICH RECEPTOR-LIKE PROTEIN KINASES (CRKs) and PLASMODESMATA-LOCALIZED PROTEINS (PDLPs). The DUF26 is land plant-specific but structural analyses of PDLP ectodomains revealed strong similarity to fungal lectins and thus may constitute a group of plant carbohydrate-binding proteins. CRKs expanded through tandem duplications and preferential retention of duplicates following whole genome duplications, whereas PDLPs evolved according to the dosage balance hypothesis. We propose that new gene families mainly expand through small-scale duplications, while fractionation and genetic drift after whole genome multiplications drive families towards dosage balance.

大的基因家族是植物基因组的一个主要特征，这些基因家族大小的变异是植物适应性进化的关键因素。然而，基因和基因组复制为功能基因鉴定和遗传转化研究带来了很多的困难。本文中，作者研究了含有DUF26结构域蛋白的演化历史。DUF26主要存在于分泌蛋白中。结构域的复制和重组产生了富含半胱氨酸类受体蛋白激酶CRK和胞间连丝定位蛋白PDLP。DUF26是陆地植物所特有的，但对于PDLP胞外结构域的结构分析显示其与真菌凝集素具有非常高的相似性，因此可能构成一类植物糖类结合蛋白。CRK通过串联重复进行了扩张，并且在全基因组复制事件之后CRK复制产生的同源基因优先得到了保留，而PDLP则通过剂量平衡假说的方式演化。作者提出新的基因家族主要通过小范围的复制事件进行扩张，而全基因组复制事件之后的片段化和遗传漂变会驱动基因家族达到剂量平衡。

通讯：Michael Wrzaczek (https://www.helsinki.fi/en/researchgroups/plant-receptors/team)

个人简介：维也纳大学，博士。

研究方向：植物类受体蛋白激酶的功能及演化。

doi: https://doi.org/10.1038/s42003-019-0306-9

Journal: Communications Biology

First Published: February 08, 2019