Fulvic acid ameliorates drought stress-induced damage in tea plants by regulating the ascorbate metabolism and flavonoids biosynthesis

Abstract

Background: 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. Results: 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 Lascorbate), 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. Conclusion: 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.

Recent Advances in the Molecular Effects of Biostimulants in Plants: An Overview

“…For instance, drought stress leads to a rapid accumulation of reactive oxygen species (ROS) in plant tissue, causing a variety of negative effects at the cellular level [66], which can be attenuated by the function of ascorbic acid. Notably, FA application was shown to improve ascorbate, glutathione and flavonoids, by the upregulation of genes related to their metabolism, ameliorating the negative effects of drought stress [67,68].…”

Genome-wide identification, characterization and expression analysis of the expansin gene family under drought stress in tea (Camellia sinensis L.)

“…In this study, identification of expansins, its superfamily organization, characterization and expression analysis in response to drought stress was investigated. Out of the three bioprojects taken, research works from two bioprojects related to drought stress in tea have already been published (59,60). Using the transcriptomic data from all three bioprojects, we have explored the biological role of expansin genes during drought stress in tea.…”

Transcriptomics of Biostimulation of Plants Under Abiotic Stress

“…The effect of fulvic acid in tea plants ( Camellia sinensis ) under drought stress was studied ( Sun et al, 2020 ). The authors examined the transcriptomics and metabolomics profiles, 604 and 3331 differentially expressed metabolite genes (DEGs) were found in plants at 4 and 8 days under drought respectively.…”