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.)
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.)
复制标题
全长转录本测序和比较转录组分析，以评估渗透和离子胁迫成分对栽培苜蓿 (Medicago sativa L.) 根耐盐性的贡献
DOI：
10.1186/s12870-019-1630-4
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发表时间：
2019-01-21
影响因子：
5.3
通讯作者：
Liu, Zhipeng
中科院分区：
文献类型：
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作者：
Luo, Dong;Zhou, Qiang;Liu, Zhipeng
研究背景：苜蓿是世界上种植最广泛的豆科牧草。盐度是影响紫花苜蓿生产力的主要环境因子。然而，关于苜蓿对盐胁迫反应的分子机制，特别是渗透胁迫和离子胁迫两个重要组分的相对贡献，目前还知之甚少。在本研究中，我们构建了第一个苜蓿根尖在连续NaCl和甘露醇处理1，3，6，12和24 h下的全长转录组数据库（每个时间点三个生物学重复，包括对照组）通过PacBio Iso-Seq。这导致了52，787个全长转录本的鉴定，平均长度为2551 bp。然后通过BGISEQ-500 RNA-Seq分析相同33个应激样品中的总体转录变化。共鉴定了8861个NaCl调节的和8016个甘露醇调节的差异表达基因（DEG）。代谢分析表明，这些DEG重叠或分歧的级联分子网络参与信号感知，信号转导，转录调控和抗氧化防御。值得注意的是，几个充分表征的信号传导途径，如CDPK，MAPK，CIPK和PYL-PP 2C-SnRK 2，被证明参与渗透胁迫，而SOS核心途径被离子胁迫激活。此外，过氧化氢酶和过氧化物酶的活性，谷胱甘肽和脯氨酸含量的生理变化是根据相关基因的动态转录谱，表明抗氧化防御系统起着关键作用，在响应salt stress.Conclusions：总体而言，我们的研究提供了证据，苜蓿对盐胁迫的反应包括渗透和离子成分。这些与渗透胁迫和离子胁迫相关的关键基因是通过基因工程提高植物抗盐胁迫能力的潜在靶基因。
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 dynamic transcript profiles of the relevant genes, indicating that antioxidative defense system plays critical roles in response to salinity stress.Conclusions: Overall, our study provides evidence that the response to salinity stress in alfalfa includes both osmotic and ionic components. The key osmotic and ionic stress-related genes are candidates for future studies as potential targets to improve resistance to salinity stress via genetic engineering.