title: Transcriptome analysis reveals diversified adaptation of Stipa purpurea along a drought gradient on the Tibetan Plateau.
abstract: Natural selection drives species adaptations to biotic and abiotic stresses. Species distributed along a moisture gradient, such as Stipa purpurea, a dominant grass in alpine arid and semi-arid meadows on the Tibetan Plateau, provide an opportunity to evaluate the effects of long-term adaptation to differing degrees of drought stress on gene expression. However, the genetic basis of this divergence remains largely unknown. Next-generation sequencing technologies have provided important genome-wide insights on the evolution of organisms for which genomic information is lacking. To understand how S. purpurea responds to drought stress, we selected five populations distributed along the degressive rainfall line on the northwestern Tibetan Plateau that currently present evolutionary acclimation to localized drought pressure at the physiological and biochemical levels and compared their transcriptome responses. In addition, we performed de novo assembly of the S. purpurea transcriptome using short read sequencing technology and successfully assembled 84,298 unigenes from approximately 51 million sequencing reads. We quantified gene expression level to compare their transcriptome responses using mRNA-Seq and identified differentially expressed transcripts that are involved in primary and secondary plant metabolism, plant hormone synthesis, defense responses, and cell wall synthesis. Furthermore, physiological and biochemical evidence supports that abscisic acid (ABA) accumulation and cell wall strengthening derived from the differential transcripts contribute to the tolerance of S. purpurea to drought stress. The mechanisms by which S. purpurea adapts to drought stress provide new insight into how plants ecologically adapt and evolve.
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Science, Kunming, 650204, China.
authors.forename: Yunqiang
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiong
authors.initials: X
authors.lastname: Li
authors.forename: Xiangxiang
authors.initials: X
authors.lastname: Kong
authors.forename: Lan
authors.initials: L
authors.lastname: Ma
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Hu
authors.forename: Yongping
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000064:Acclimatization / Q000235:genetics*; D002473:Cell Wall / Q000648:ultrastructure; D055864:Droughts; D020869:Gene Expression Profiling; D063990:Gene Ontology; D058977:Molecular Sequence Annotation; D010940:Plant Proteins / Q000235:genetics; D006109:Poaceae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D017423:Sequence Analysis, RNA; D013312:Stress, Physiological / Q000235:genetics; D018609:Tibet; D059467:Transcriptome
chemical_list: D010940:Plant Proteins