PDF(Pubmed)
Abstract：
How organisms respond to environmental stress is a key topic in evolutionary biology. This study focused on the genomic evolution of Laburnicola rhizohalophila, a dark-septate endophytic fungus from roots of a halophyte. Chromosome-level assemblies were generated from five representative isolates from structured subpopulations. The data revealed significant genomic plasticity resulting from chromosomal polymorphisms created by fusion and fission events, known as dysploidy. Analyses of genomic features, phylogenomics, and macrosynteny have provided clear evidence for the origin of intraspecific diploid-like hybrids. Notably, one diploid phenotype stood out as an outlier and exhibited a conditional fitness advantage when exposed to a range of abiotic stresses compared with its parents. By comparing the gene expression patterns in each hybrid parent triad under the four growth conditions, the mechanisms underlying growth vigor were corroborated through an analysis of transgressively upregulated genes enriched in membrane glycerolipid biosynthesis and transmembrane transporter activity. In vitro assays suggested increased membrane integrity and lipid accumulation, as well as decreased malondialdehyde production under optimal salt conditions (0.3 M NaCl) in the hybrid. These attributes have been implicated in salinity tolerance. This study supports the notion that hybridization-induced genome doubling leads to the emergence of phenotypic innovations in an extremophilic endophyte.
摘要：
生物体如何应对环境压力是进化生物学的关键课题。本研究的重点是拉伯尼科拉根性嗜盐的基因组进化，一种来自盐生植物根的深色间隔内生真菌。从来自结构化亚群的五个代表性分离株产生染色体水平组装体。数据显示，融合和裂变事件产生的染色体多态性导致了显着的基因组可塑性，称为多倍体。基因组特征分析，系统基因组学，和大同化关系为种内二倍体样杂种的起源提供了明确的证据。值得注意的是,与其亲本相比，当暴露于一系列非生物胁迫时，一种二倍体表型表现为异常值，并表现出条件适应性优势。通过比较四种生长条件下每个杂种亲本三联体的基因表达模式，通过分析富含膜甘油脂生物合成和跨膜转运蛋白活性的过度上调基因，证实了生长活力的潜在机制。体外实验表明膜完整性和脂质积累增加，在最佳盐条件（0.3MNaCl）下，杂种的丙二醛产量也降低。这些属性与盐度耐受性有关。这项研究支持以下观点：杂交诱导的基因组加倍导致在嗜极端内生菌中出现表型创新。
