The salinization and alkalization of soil are widespread environmental problems. Sugar beet (B. vulgaris L.) is a moderately salt tolerant glycophyte, but little is known about the different mechanisms of sugar beet response to salt and alkaline stresses. The aim of this study was to investigate the influence of neutral salt (NaCl:Na₂SO₄, 1:1) and alkaline salt (Na₂CO₃) treatment on physiological and transcriptome changes in sugar beet. We found that a low level of neutral salt (NaCl:Na₂SO₄; 1:1, Na⁺ 25 mM) or alkaline salt (Na₂CO₃, Na⁺ 25 mM) significantly enhanced total biomass, leaf area and photosynthesis indictors in sugar beet. Under a high concentration of alkaline salt (Na₂CO₃, Na⁺ 100 mM), the growth of plants was not significantly affected compared with the control. But a high level of neutral salt (NaCl: Na₂SO₄; 1:1, Na⁺ 100 mM) significantly inhibited plant growth and photosynthesis. Furthermore, sugar beet tends to synthesize higher levels of soluble sugar and reducing sugar to cope with high neutral salt stress, and more drastic changes in indole acetic acid (IAA) and abscisic acid (ABA) contents were detected. We used next-generation RNA-Seq technique to analyze transcriptional changes under neutral salt and alkaline salt treatment in sugar beet. Overall, 4,773 and 2,251 differentially expressed genes (DEGs) were identified in leaves and roots, respectively. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that genes involving cutin, suberine and wax biosynthesis, sesquiterpenoid and triterpenoid biosynthesis and flavonoid biosynthesis had simultaneously changed expression under low neutral salt or alkaline salt, so these genes may be related to stimulating sugar beet growth in both low salt treatments. Genes enriched in monoterpenoid biosynthesis, amino acids metabolism and starch and sucrose metabolism were specifically regulated to respond to the high alkaline salt. Meanwhile, compared with high alkaline salt, high neutral salt induced the expression change of genes involved in DNA replication, and decreased the expression of genes participating in cutin, suberine and wax biosynthesis, and linoleic acid metabolism. These results indicate the presence of different mechanisms responsible for sugar beet responses to neutral salt and alkaline salt stresses.

土壤的盐碱化是普遍的环境问题。甜菜 （寻常芽孢杆菌L.）是一种中度耐盐的植物，但对甜菜对盐和碱胁迫的不同反应机理知之甚少。本研究的目的是研究中性盐（NaCl：Na ₂ SO _4，1：1）和碱性盐（Na ₂ CO ₃）处理对甜菜生理和转录组变化的影响。我们发现低水平的中性盐（NaCl：Na ₂ SO ₄； 1：1，Na ⁺ 25 mM）或碱性盐（Na ₂ CO ₃，Na ⁺ 25 mM）显着提高了总生物量，叶面积和光合作用指标在甜菜中。在高浓度的碱盐（Na₂ CO ₃，Na ⁺ 100 mM），与对照相比，植物的生长没有受到明显影响。但是中性盐含量很高（NaCl：Na ₂ SO ₄ ; 1：1，Na ⁺100 mM）显着抑制植物的生长和光合作用。此外，甜菜趋向于合成更高水平的可溶性糖和还原糖以应对高中性盐胁迫，并且检测到吲哚乙酸（IAA）和脱落酸（ABA）含量变化更大。我们使用了下一代RNA-Seq技术来分析甜菜在中性盐和碱性盐处理下的转录变化。总体而言，在叶和根中分别鉴定到4,773和2,251个差异表达基因（DEG）。《京都议定书》的基因和基因组百科全书（KEGG）分析表明，涉及角质，蛇皮和蜡生物合成，倍半萜和三萜生物合成以及类黄酮生物合成的基因在低中性盐或碱性盐下同时改变了表达，因此在低盐处理中，这些基因可能与刺激甜菜的生长有关。对富含单萜类生物合成，氨基酸代谢以及淀粉和蔗糖代谢的基因进行了专门调节，以响应高碱性盐。同时，与高碱性盐相比，高中性盐诱导参与DNA复制的基因表达变化，并降低参与角质，蛋氨酸和蜡生物合成以及亚油酸代谢的基因表达。这些结果表明存在不同机制负责甜菜对中性盐和碱性盐胁迫的响应。氨基酸代谢以及淀粉和蔗糖代谢受到特殊调节，以响应高碱性盐。同时，与高碱性盐相比，高中性盐诱导参与DNA复制的基因表达变化，并降低参与角质，蛋氨酸和蜡生物合成以及亚油酸代谢的基因表达。这些结果表明存在不同机制负责甜菜对中性盐和碱性盐胁迫的响应。氨基酸代谢以及淀粉和蔗糖代谢受到特殊调节，以响应高碱性盐。同时，与高碱性盐相比，高中性盐诱导参与DNA复制的基因表达变化，并降低参与角质，蛋氨酸和蜡生物合成以及亚油酸代谢的基因表达。这些结果表明存在不同机制负责甜菜对中性盐和碱性盐胁迫的响应。