Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, 621000, China.
College of Life Sciences and Engineering, Henan University of Urban Construction, Pingdingshan, 467036, Henan, China.
BMC Plant Biol. 2021 Oct 25;21(1):489. doi: 10.1186/s12870-021-03274-1.
Soil salinization is causing ecosystem degradation and crop yield reduction worldwide, and elucidation of the mechanism of salt-tolerant plants to improve crop yield is highly significant. Podocarpus macrophyllus is an ancient gymnosperm species with a unique environmental adaptation strategy that may be attributed to its lengthy evolutionary process. The present study investigated the physiological and molecular responses of P. macrophyllus plants to salt stress by analyzing its photosynthetic system and antioxidant enzyme activity. We also analyzed the differentially expressed genes (DEGs) in P. macrophyllus under salt stress using RNA sequencing and de novo transcriptome assembly.
Salt treatment significantly affected the photosynthetic system in P. macrophyllus seedlings, which decreased chlorophyll content, altered chloroplast ultrastructure, and reduced photosynthesis. The activities of antioxidant enzymes increased significantly following salt stress treatment. Transcriptome analysis showed that salt stress induced a large number of genes involved in multiple metabolic and biological regulation processes. The transcription levels of genes that mediate phytohormone transport or signaling were altered. K and Ca transporter-encoding genes and the MYB transcription factor were upregulated under salt stress. However, the genes involved in cell wall biosynthesis and secondary metabolism were downregulated.
Our research identified some important pathways and putative genes involved in salt tolerance in P. macrophyllus and provided clues for elucidating the mechanism of salt tolerance and the utilization of the salt tolerance genes of P. macrophyllus for crop improvement.
土壤盐渍化正在导致全球范围内的生态系统退化和作物产量减少，阐明耐盐植物的机制对于提高作物产量具有重要意义。罗汉松是一种古老的裸子植物，具有独特的环境适应策略，这可能归因于其漫长的进化过程。本研究通过分析罗汉松的光合作用系统和抗氧化酶活性，研究了其对盐胁迫的生理和分子响应。我们还通过 RNA 测序和从头转录组组装分析了罗汉松在盐胁迫下的差异表达基因（DEGs）。
盐处理显著影响了罗汉松幼苗的光合作用系统，降低了叶绿素含量，改变了叶绿体超微结构，降低了光合作用。抗氧化酶活性在盐胁迫处理后显著增加。转录组分析表明，盐胁迫诱导了大量参与多种代谢和生物调节过程的基因。介导植物激素运输或信号转导的基因的转录水平发生了改变。盐胁迫下 K 和 Ca 转运蛋白编码基因和 MYB 转录因子上调，但参与细胞壁生物合成和次生代谢的基因下调。
本研究鉴定了罗汉松耐盐过程中一些重要的途径和可能的基因，为阐明罗汉松耐盐机制以及利用罗汉松的耐盐基因进行作物改良提供了线索。
