CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266200, China.
Commun Biol. 2024 Oct 23;7(1):1378. doi: 10.1038/s42003-024-07068-7.
Of the hitherto over 60 taxonomically identified species in the genus of Pseudo-nitzschia, 26 have been confirmed to be toxigenic. Nevertheless, the acquisition and evolution of the toxin biosynthesis (dab) genes by this extensive group of Pseudo-nitzschia species remains unclear. Through constructing chromosome-level genomes of three Pseudo-nitzschia species and draft genomes of ten additional Pseudo-nitzschia species, putative genomic integration sites for the dab genes in Pseudo-nitzschia species were explored. A putative breakpoint was observed in syntenic regions in the dab gene cluster-lacking Pseudo-nitzschia species, suggesting potential independent losses of dab genes. The breakpoints between this pair of conserved genes were also identified in some dab genes-possessing Pseudo-nitzschia species, suggesting that the dab gene clusters transposed to other loci after the initial integration. A "single acquisition, multiple independent losses (SAMIL)" model is proposed to explain the acquisition and evolution of the dab gene cluster in Pseudo-nitzschia species.
迄今为止，在菱形藻属中已鉴定出的 60 多种分类学上的物种中，有 26 种被证实具有产毒能力。然而，这个广泛的菱形藻物种群体获得和进化毒素生物合成（dab）基因的情况仍不清楚。通过构建三个菱形藻物种的染色体水平基因组和另外十个菱形藻物种的草案基因组，探索了菱形藻物种中 dab 基因的可能基因组整合位点。在缺乏 dab 基因簇的菱形藻物种的同源区域中观察到一个假定的断裂点，表明 dab 基因可能存在独立缺失。在一些具有 dab 基因的菱形藻物种中也鉴定到这对保守基因之间的断点，表明 dab 基因簇在最初整合后转移到了其他基因座。提出了“单一获得，多个独立缺失（SAMIL）”模型来解释菱形藻物种 dab 基因簇的获得和进化。
