Sui Na, Wang Yu, Liu Shanshan, Yang Zhen, Wang Fang, Wan Shubo
Shandong Provincial Key Laboratory of Plant Stress, College of Life Science, Shandong Normal University, Jinan, China.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.
Front Plant Sci. 2018 Jan 22;9:7. doi: 10.3389/fpls.2018.00007. eCollection 2018.
Peanut ( L.) is one of the five major oilseed crops cultivated worldwide. Salt stress is a common adverse condition for the growth of this crop in many countries and regions. In this study, physiological parameters and transcriptome profiles of peanut seedlings exposed to salt stress (250 mM NaCl for 4 days, S4) and recovery for 3 days (when transferred to standard conditions for 3 days, R3) were analyzed to detect genes associated with salt stress and recovery in peanut. We observed that the quantum yield of PSII electron transport (ΦPSII) and the maximal photochemical efficiency of PSII (/) decreased in S4 compared with the control, and increased in R3 compared with those in S4. Seedling fresh weight, dry weight and PSI oxidoreductive activity (Δ/) were inhibited in S4 and did not recover in R3. Superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities decreased in S4 and increased in R3, whereas superoxide anion ([Formula: see text]) and hydrogen peroxide (HO) contents increased in S4 and decreased in R3. Transcriptome analysis revealed 1,742 differentially expressed genes (DEGs) under salt stress and 390 DEGs under recovery. Among these DEGs, two DEGs encoding ω-3 fatty acid desaturase that synthesized linolenic acid (18:3) from linoleic acid (18:2) were down-regulated in S4 and up-regulated in R3. Furthermore, ω-3 fatty acid desaturase activity decreased under salt stress and increased under recovery. Consistent with this result, 18:3 content decreased under salt stress and increased under recovery compared with that under salt treatment. In conclusion, salt stress markedly changed the activity of ω-3 fatty acid desaturase and fatty acid composition. The findings provide novel insights for the improvement of salt tolerance in peanut.
花生（Arachis hypogaea L.）是全球种植的五大主要油料作物之一。盐胁迫是许多国家和地区该作物生长常见的不利条件。在本研究中，分析了暴露于盐胁迫（250 mM NaCl处理4天，S4）及恢复3天（转移至标准条件3天，R3）的花生幼苗的生理参数和转录组图谱，以检测花生中与盐胁迫和恢复相关的基因。我们观察到，与对照相比，S4中PSII电子传递的量子产率（ΦPSII）和PSII的最大光化学效率（Fv/Fm）降低，而与S4相比，R3中则升高。S4中幼苗鲜重、干重和PSI氧化还原活性（ΔI/I）受到抑制，且在R3中未恢复。超氧化物歧化酶（SOD）和抗坏血酸过氧化物酶（APX）活性在S4中降低，在R3中升高，而超氧阴离子（O₂⁻）和过氧化氢（H₂O₂）含量在S4中增加，在R3中降低。转录组分析揭示了盐胁迫下1742个差异表达基因（DEGs）和恢复过程中有390个DEGs。在这些DEGs中，两个编码ω-3脂肪酸去饱和酶的DEGs，其从亚油酸（18:2）合成亚麻酸（18:3），在S4中下调，在R3中上调。此外，ω-3脂肪酸去饱和酶活性在盐胁迫下降低，在恢复过程中升高。与该结果一致，与盐处理相比，18:3含量在盐胁迫下降低，在恢复过程中升高。总之，盐胁迫显著改变了ω-3脂肪酸去饱和酶的活性和脂肪酸组成。这些发现为提高花生耐盐性提供了新的见解。
