Full-length transcript sequencing and comparative transcriptomic analysis to evaluate the contribution of osmotic and ionic stress components towards salinity tolerance in the roots of cultivated alfalfa (Medicago sativa L.)

作者：Dong Luo, Qiang Zhou, Yuguo Wu, Xutian Chai, Wenxian Liu, Yanrong Wang, Qingchuan Yang, Zeng‐Yu Wang, Zhipeng Liu · 发表于：BMC Plant Biology · 年份：2019 · DOI：10.1186/s12870-019-1630-4 · 被引用次数：157 · 研究领域：Plant Stress Responses and Tolerance、Plant Molecular Biology Research、Plant responses to water stress

BACKGROUND: Alfalfa is the most extensively cultivated forage legume. Salinity is a major environmental factor that impacts on alfalfa's productivity. However, little is known about the molecular mechanisms underlying alfalfa responses to salinity, especially the relative contribution of the two important components of osmotic and ionic stress. RESULTS: In this study, we constructed the first full-length transcriptome database for alfalfa root tips under continuous NaCl and mannitol treatments for 1, 3, 6, 12, and 24 h (three biological replicates for each time points, including the control group) via PacBio Iso-Seq. This resulted in the identification of 52,787 full-length transcripts, with an average length of 2551 bp. Global transcriptional changes in the same 33 stressed samples were then analyzed via BGISEQ-500 RNA-Seq. Totals of 8861 NaCl-regulated and 8016 mannitol-regulated differentially expressed genes (DEGs) were identified. Metabolic analyses revealed that these DEGs overlapped or diverged in the cascades of molecular networks involved in signal perception, signal transduction, transcriptional regulation, and antioxidative defense. Notably, several well characterized signalling pathways, such as CDPK, MAPK, CIPK, and PYL-PP2C-SnRK2, were shown to be involved in osmotic stress, while the SOS core pathway was activated by ionic stress. Moreover, the physiological shifts of catalase and peroxidase activity, glutathione and proline content were in accordance with dyna...