Wang Dan, Zhang Lin, Hu JunFeng, Gao Dianshuai, Liu Xin, Sha Yan
School of Medical Information of Xuzhou Medical University, Xuzhou, 221004, China.
School of Nursing of Xuzhou Medical University, Research Center for Neurobiology of Xuzhou Medical University, Xuzhou, 221004, China.
Genetica. 2018 Apr;146(2):179-185. doi: 10.1007/s10709-018-0010-6. Epub 2018 Feb 22.
Lipases are physiologically important and ubiquitous enzymes that share a conserved domain and are classified into eight different families based on their amino acid sequences and fundamental biological properties. The Lipase3 family of lipases was reported to possess a canonical fold typical of α/β hydrolases and a typical catalytic triad, suggesting a distinct evolutionary origin for this family. Genes in the Lipase3 family do not have the same functions, but maintain the conserved Lipase3 domain. There have been extensive studies of Lipase3 structures and functions, but little is known about their evolutionary histories. In this study, all lipases within five plant species were identified, and their phylogenetic relationships and genetic properties were analyzed and used to group them into distinct evolutionary families. Each identified lipase family contained at least one dicot and monocot Lipase3 protein, indicating that the gene family was established before the split of dicots and monocots. Similar intron/exon numbers and predicted protein sequence lengths were found within individual groups. Twenty-four tandem Lipase3 gene duplications were identified, implying that the distinctive function of Lipase3 genes appears to be a consequence of translocation and neofunctionalization after gene duplication. The functional genes EDS1, PAD4, and SAG101 that are reportedly involved in pathogen response were all located in the same group. The nucleotide diversity (Dxy) and the ratio of nonsynonymous to synonymous nucleotide substitutions rates (Ka/Ks) of the three genes were significantly greater than the average across the genomes. We further observed evidence for selection maintaining diversity on three genes in the Toll-Interleukin-1 receptor type of nucleotide binding/leucine-rich repeat immune receptor (TIR-NBS LRR) immunity-response signaling pathway, indicating that they could be vulnerable to pathogen effectors.
脂肪酶是生理上重要且普遍存在的酶，它们共享一个保守结构域，并根据其氨基酸序列和基本生物学特性分为八个不同的家族。据报道，脂肪酶的脂肪酶3家族具有典型的α/β水解酶折叠结构和典型的催化三联体，这表明该家族有独特的进化起源。脂肪酶3家族中的基因功能并不相同，但都保留了保守的脂肪酶3结构域。虽然对脂肪酶3的结构和功能已有广泛研究，但对其进化历史却知之甚少。在本研究中，我们鉴定了五种植物中的所有脂肪酶，并分析了它们的系统发育关系和遗传特性，以便将它们归类到不同的进化家族中。每个鉴定出的脂肪酶家族至少包含一个双子叶植物和单子叶植物的脂肪酶3蛋白，这表明该基因家族在双子叶植物和单子叶植物分化之前就已形成。在各个组中发现了相似的内含子/外显子数量和预测的蛋白质序列长度。我们鉴定出24个串联的脂肪酶3基因重复，这意味着脂肪酶3基因独特的功能似乎是基因重复后易位和新功能化的结果。据报道参与病原体反应的功能基因EDS1、PAD4和SAG101都位于同一组中。这三个基因的核苷酸多样性（Dxy）以及非同义核苷酸替换率与同义核苷酸替换率之比（Ka/Ks）均显著高于全基因组的平均值。我们进一步观察到在Toll样白细胞介素-1受体型核苷酸结合/富含亮氨酸重复序列免疫受体（TIR-NBS LRR）免疫反应信号通路中的三个基因上存在选择维持多样性的证据，这表明它们可能易受病原体效应子的影响。
