Carbohydrate-active enzymes (CAZymes) are a cornerstone in the phytopathogenicity of filamentous microbes. CAZymes are required for every step of a successful infection cycle—from penetration, to nutrient acquisition (during colonization), to exit and dispersal. Yet, CAZymes are not a unique feature of filamentous pathogens. They are found across eukaryotic genomes and including, for example, saprotrophic relatives of major pathogens. Comparative genomics and functional analyses revealed that CAZyme content is shaped by a multitude of factors, including utilized substrate, lifestyle, and host preference. Yet, family size alone says little about usage. Indeed, in a previous study, we found that genes putatively coding for the CAZyme families of carbohydrate esterase (CE)1 and CE10, while not specifically enriched in number, were suggested to have lifestyle-specific gene expression patterns. Here, we used comparative genomics and a clustering approach to understand how the repertoire of the CE1- and CE10-encoding gene families is shaped across oomycete evolution. These data are combined with comparative transcriptomic analyses across homologous clusters within the gene families. We find that CE1 and CE10 have been reduced in number in biotrophic oomycetes independent of the phylogenetic relationship of the biotrophs to each other. The reduction in CE1 is different from that observed for CE10: While in CE10 specific clusters of homologous sequences show convergent reduction, CE1 reduction is caused by species-specific losses. Comparative transcriptomics revealed that some clusters of CE1 or CE10 sequences have a higher expression than others, independent of the species composition within them. Further, we find that CE1- and CE10-encoding genes are mainly induced in plant pathogens and that some homologous genes show lifestyle-specific gene expression levels during infection, with hemibiotrophs showing the highest expression levels.

碳水化合物活性酶（CAZymes）是丝状微生物致病性的基石。成功感染周期的每个步骤都需要使用酵素，从渗透到养分吸收（定居期间），再到扩散。然而，CAZymes不是丝状病原体的独特特征。它们遍布真核基因组，包括例如主要病原体的腐养亲属。比较基因组学和功能分析表明，CAZyme含量受多种因素影响，包括利用的底物，生活方式和宿主偏好。然而，仅家庭规模本身并不能说明使用情况。的确，在先前的研究中，我们发现推定编码碳水化合物酯酶（CE）1和CE10的CAZyme家族的基因，但数量并未特别丰富，建议具有特定生活方式的基因表达模式。在这里，我们使用比较基因组学和聚类方法来了解CE1和CE10编码基因家族的组成如何在卵菌进化过程中形成。这些数据与基因家族内同源簇的比较转录组学分析相结合。我们发现CE1和CE10的数量减少了生物营养性卵母细胞，而与生物营养性彼此之间的系统发育关系无关。CE1的减少与CE10的减少不同：虽然在CE10中，同源序列的特定簇显示收敛性减少，但CE1减少是由物种特异性损失引起的。比较转录组学研究表明，CE1或CE10序列的某些簇比其他簇具有更高的表达，与其中的物种组成无关。此外，我们发现，CE1-和CE10编码基因主要在植物病原体中诱导，并且某些同源基因在感染过程中表现出生活方式特异性基因表达水平，其中半生养生物显示最高表达水平。