Wang Cui, Wang Tong, Yin Meiqi, Eller Franziska, Liu Lele, Brix Hans, Guo Weihua
Institute of Ecology and Biodiversity, Shandong Provincial Engineering and Technology Research Center for Vegetation Ecology, School of Life Sciences, Shandong University, Qingdao, China.
Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
Front Plant Sci. 2021 May 5;12:653183. doi: 10.3389/fpls.2021.653183. eCollection 2021.
Polyploidization in plants is thought to have occurred as coping mechanism with environmental stresses. Polyploidization-driven adaptation is often achieved through interplay of gene networks involved in differentially expressed genes, which triggers the plant to evolve special phenotypic traits for survival. is a cosmopolitan species with highly variable phenotypic traits and high adaptation capacity to various habitats. The species' ploidy level varies from 3x to 12x, thus it is an ideal organism to investigate the molecular evolution of polyploidy and gene regulation mediated by different numbers of chromosome copies. In this study, we used high-throughput RNAseq data as a tool, to analyze the gene expression profiles in tetraploid and octoploid . The estimated divergence time between tetraploid and octoploid was dated to the border between Pliocene and Pleistocene. This study identified 439 up- and 956 down-regulated transcripts in tetraploids compared to octoploids. Gene ontology and pathway analysis revealed that tetraploids tended to express genes responsible for reproduction and seed germination to complete the reproduction cycle early, and expressed genes related to defense against UV-B light and fungi, whereas octoploids expressed mainly genes related to thermotolerance. Most differentially expressed genes were enriched in chaperones, folding catalysts and protein processing in endoplasmic reticulum pathways. Multiple biased isoform usage of the same gene was detected in differentially expressed genes, and the ones upregulated in octoploids were related to reduced DNA methylation. Our study provides new insights into the role of polyploidization on environmental responses and potential stress tolerance in grass species.
植物中的多倍体化被认为是一种应对环境压力的机制。多倍体化驱动的适应性通常是通过参与差异表达基因的基因网络之间的相互作用来实现的，这促使植物进化出特殊的表型特征以生存。是一种世界性物种，具有高度可变的表型特征和对各种栖息地的高适应能力。该物种的倍性水平从3x到12x不等，因此它是研究多倍体分子进化和由不同数量染色体拷贝介导的基因调控的理想生物体。在本研究中，我们使用高通量RNAseq数据作为工具，分析四倍体和八倍体中的基因表达谱。四倍体和八倍体之间的估计分歧时间可追溯到上新世和更新世之间的边界。与八倍体相比，本研究在四倍体中鉴定出439个上调转录本和956个下调转录本。基因本体论和通路分析表明，四倍体倾向于表达负责繁殖和种子萌发的基因，以便尽早完成繁殖周期，并表达与抵御UV-B光和真菌相关的基因，而八倍体主要表达与耐热性相关的基因。大多数差异表达基因在内质网途径中的伴侣蛋白、折叠催化剂和蛋白质加工中富集。在差异表达基因中检测到同一基因的多个偏向性异构体使用情况，八倍体中上调的那些与DNA甲基化减少有关。我们的研究为多倍体化在禾本科物种环境响应和潜在胁迫耐受性方面的作用提供了新的见解。
