【目的】研究全缘冬青(Ilex integra)和红果冬青(I. purpurea)的根系在NaCl胁迫处理中的转录组活性差异,为进一步研究二者耐盐性差异的生理学机理奠定基础。【方法】以内含250 mmol/L NaCl的1/2浓度霍格兰德溶液对全缘冬青和红果冬青的两年生扦插苗进行盐胁迫处理,采集经0(盐处理前)、6和72 h盐处理的根系样品,提取总RNA,进行转录组测序,组装转录本,筛选差异表达基因,分析两种冬青根系中的功能富集通路和特定代谢途径的基因表达变化。【结果】全缘冬青根系盐处理6 h的差异表达基因数量为2 616,盐处理72 h为1 802;而红果冬青根系盐处理6 h的差异表达基因数量为1 831,盐处理72 h为3 490。全缘冬青盐处理6和72 h根系中共同的KEGG富集途径为植物激素信号转导、亚油酸代谢、类胡萝卜素生物合成和甜菜红素生物合成,红果冬青根系6和72 h盐处理共同的KEGG富集途径为植物激素信号转导、苯丙烷生物合成和类胡萝卜素生物合成。甜菜红素生物合成和亚油酸/花生四烯酸代谢为盐胁迫处理全缘冬青根系中特有的富集代谢通路。全缘冬青中受盐胁迫正调控的过氧化氢酶基因数多于红果冬青的,并且在盐处理下其表达水平远高于红果冬青的。【结论】全缘冬青根系较强的耐盐性可能与植物激素信号转导、类胡萝卜素生物合成、甜菜红素生物合成和脂肪酸脂类代谢等生理过程相关联;盐处理下过氧化氢酶基因的高效表达也可能是全缘冬青根系具较强耐盐性的因素之一。

【Objective】 This research aims to investigate the difference in transcriptomic activity of Ilex integra and I. purpurea roots using NaCl salt treatments and provide insights for future study on the physiological mechanisms responsible for differential salt tolerance between these Ilex species. 【Method】 Two-year-old cutting seedlings of I. integra and I. purpurea were irrigated with half-strength Hoagland solution containing 250 mmol/L NaCl for salt treatments. Root samples were collected at 0(before salt treatment), 6 and 72 h after salt treatments. The total RNAs were extracted for transcriptomic RNA-Seq. Transcripts were assembled and differentially expressed genes (DEGs) were selected. The enriched KEGG functional pathways for the two species were compared, and the expression of genes involved in certain metabolic pathways was analyzed. 【Result】 There were 2 616 and 1 802 DEGs in 6 h-salt-treated and 72 h-salt-treated I. integra roots respectively, while there were 1 831 and 3 490 DEGs in 6 h-salt-treated and 72 h-salt-treated I. purpurea roots, respectively. The common enriched KEGG functional pathways between I. integra roots with 6 and 72 h salt treatments were plant hormone signal transduction, linoleic acid metabolism, carotenoid biosynthesis and betalain biosynthesis. The common enriched pathways between I. integra roots with 6 and 72 h salt treatments were plant hormone signal transduction, phenylpropanoid biosynthesis and carotenoid biosynthesis. Betalain biosynthesis and linoleic acid/arachidonic acid metabolism are unique pathways in I. integra roots during salt treatments. There were more up-regulated putative catalase genes with much higher expression levels in salt-treated I. integra roots than that in the I. purpurea roots. 【Conclusion】 The higher salt tolerance of I. integra roots may be associated with physiological processes such as plant hormone signal transduction, carotenoid biosynthesis, betalain biosynthesis and fatty acid metabolism. The higher expression of catalase genes during salt treatments may also contribute to the higher salt tolerance of I. integra roots.