Tea Research Institute, Qingdao Agricultural University, Qingdao, 266109, Shandong, China.
Murdoch University, Perth, 6150, Australia.
BMC Genomics. 2020 Jun 18;21(1):411. doi: 10.1186/s12864-020-06815-4.
Fulvic acid (FA) is a kind of plant growth regulator, which can promote plant growth, play an important role in fighting against drought, improve plant stress resistance, increase production and improve quality. However, the function of FA in tea plants during drought stress remain largely unknown.
Here, we examined the effects of 0.1 g/L FA on genes and metabolites in tea plants at different periods of drought stress using transcriptomics and metabolomics profiles. Totally, 30,702 genes and 892 metabolites were identified. Compared with controlled groups, 604 and 3331 differentially expressed metabolite genes (DEGs) were found in FA-treated tea plants at 4 days and 8 days under drought stress, respectively; 54 and 125 differentially expressed metabolites (DEMs) were also found at two time points, respectively. Bioinformatics analysis showed that DEGs and DEMs participated in diverse biological processes such as ascorbate metabolism (GME, AO, ALDH and L-ascorbate), glutathione metabolism (GST, G6PDH, glutathione reduced form and CYS-GYL), and flavonoids biosynthesis (C4H, CHS, F3'5'H, F3H, kaempferol, quercetin and myricetin). Moreover, the results of co-expression analysis showed that the interactions of identified DEGs and DEMs diversely involved in ascorbate metabolism, glutathione metabolism, and flavonoids biosynthesis, indicating that FA may be involved in the regulation of these processes during drought stress.
The results indicated that FA enhanced the drought tolerance of tea plants by (i) enhancement of the ascorbate metabolism, (ii) improvement of the glutathione metabolism, as well as (iii) promotion of the flavonoids biosynthesis that significantly improved the antioxidant defense of tea plants during drought stress. This study not only confirmed the main strategies of FA to protect tea plants from drought stress, but also deepened the understanding of the complex molecular mechanism of FA to deal with tea plants to better avoid drought damage.
富里酸（FA）是一种植物生长调节剂，能促进植物生长，在抗旱方面发挥重要作用，提高植物的抗逆性，增加产量，提高品质。然而，FA 在茶树干旱胁迫下的功能还知之甚少。
在这里，我们使用转录组学和代谢组学谱研究了 0.1g/L FA 对不同干旱胁迫时期茶树基因和代谢物的影响。共鉴定出 30702 个基因和 892 种代谢物。与对照组相比，在干旱胁迫下，FA 处理的茶树在第 4 天和第 8 天分别有 604 个和 3331 个差异表达代谢物基因（DEGs）；在两个时间点分别也发现了 54 个和 125 个差异表达代谢物（DEMs）。生物信息学分析表明，DEGs 和 DEMs 参与了多种生物过程，如抗坏血酸代谢（GME、AO、ALDH 和 L-抗坏血酸）、谷胱甘肽代谢（GST、G6PDH、还原型谷胱甘肽和 CYS-GYL）和类黄酮生物合成（C4H、CHS、F3'5'H、F3H、山奈酚、槲皮素和杨梅素）。此外，共表达分析的结果表明，鉴定的 DEGs 和 DEMs 的相互作用广泛涉及抗坏血酸代谢、谷胱甘肽代谢和类黄酮生物合成，表明 FA 可能参与了干旱胁迫过程中这些过程的调节。
该结果表明，FA 通过（i）增强抗坏血酸代谢、（ii）改善谷胱甘肽代谢以及（iii）促进类黄酮生物合成，显著提高了干旱胁迫下茶树的抗氧化防御能力，从而增强了茶树的耐旱性。本研究不仅证实了 FA 保护茶树免受干旱胁迫的主要策略，而且加深了对 FA 应对茶树应对干旱的复杂分子机制的理解，以更好地避免干旱造成的损害。
