Plants produce phylogenetically and spatially restricted, as well as structurally diverse specialized metabolites via multistep metabolic pathways. Hallmarks of specialized metabolic evolution include enzymatic promiscuity and recruitment of primary metabolic enzymes and examples of genomic clustering of pathway genes. Solanaceae glandular trichomes produce defensive acylsugars, with sidechains that vary in length across the family. We describe a tomato gene cluster on chromosome 7 involved in medium chain acylsugar accumulation due to trichome specific acyl-CoA synthetase and enoyl-CoA hydratase genes. This cluster co-localizes with a tomato steroidal alkaloid gene cluster and is syntenic to a chromosome 12 region containing another acylsugar pathway gene. We reconstructed the evolutionary events leading to this gene cluster and found that its phylogenetic distribution correlates with medium chain acylsugar accumulation across the Solanaceae. This work reveals insights into the dynamics behind gene cluster evolution and cell-type specific metabolite diversity.

中文翻译：

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茄科植物基因簇的进化和代谢多样性的出现

植物通过多步代谢途径产生系统发育和空间限制以及结构多样化的专门代谢物。专门代谢进化的标志包括酶的混杂和初级代谢酶的招募以及途径基因的基因组聚类的例子。茄科腺毛产生防御性酰基糖，其侧链长度在整个家族中有所不同。我们描述了 7 号染色体上的番茄基因簇，由于毛状体特异性酰基辅酶 A 合成酶和烯酰基辅酶 A 水合酶基因，参与中链酰基糖积累。该簇与番茄甾体生物碱基因簇共定位，并且与含有另一个酰基糖途径基因的12号染色体区域同线。我们重建了导致该基因簇的进化事件，发现其系统发育分布与茄科中链酰基糖的积累相关。这项工作揭示了对基因簇进化和细胞类型特异性代谢多样性背后的动力学的见解。