The combination of nanoparticles and endophytes boosts Thyme (Thymus vulgaris L.) resistance to drought stress by elevating levels of phenolic compounds, flavonoids, and essential oils
{"title":"The combination of nanoparticles and endophytes boosts Thyme (Thymus vulgaris L.) resistance to drought stress by elevating levels of phenolic compounds, flavonoids, and essential oils","authors":"Afsoun Kamyab, Davood Samsampour, Navid Ahmadinasab, Abdonnabi Bagheri","doi":"10.1186/s40538-024-00682-x","DOIUrl":null,"url":null,"abstract":"<div><h3>Background</h3><p>As climate change and water scarcity increasingly threaten agricultural productivity, enhancing plant resilience to drought has attracted great attention. This study explored the potential of combining Fe<sub>2</sub>O<sub>3</sub> nanoparticles (FeNPs), endophytic bacteria (EB), and endophytic fungi (EF) to boost drought tolerance in <i>Thymus vulgaris</i>. The research aimed to assess how these combined treatments affect the plant’s physiological responses and chemical composition under drought stress.</p><h3>Results</h3><p>A factorial experiment was designed using completely randomized design (CRD) method, incorporating four irrigation levels [100%, 75%, 50%, and 25% field capacity (FC)], four FeNPs concentrations (0, 0.5, 1, and 1.5 mg L<sup>−1</sup>), and three endophyte types (control, bacteria, and fungi). After extracting, purifying, identifying, and screening EB and EF from nine Lamiaceae species, the endophytes <i>Azospirillum lipoferum</i> and <i>Aspergillus oryzae</i> isolated from <i>Salvia mirzayanii</i> exhibited the highest drought resistance. The highest amounts of TFM (45.45 g) and TDM (21.56 g) were obtained using the combination of EB and FeNPs at 1 mg L<sup>−1</sup> under irrigation with 100% FC. At 25% FC, EB treatment increased the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) by 62.12% and 18.23% compared to the control, respectively. In addition, under optimal humidity conditions, FeNP concentrations were higher than 0.5 mg L<sup>−1</sup> leading to a decrease in PPO activity. At 25% FC, the highest content of total phenols was observed with a 37.5% increase under EB treatment using 1 mg L<sup>−1</sup> of FeNPs, while the highest content of total flavonoids showed a 62.72% increase under EF treatment with 0.5 mg/L of FeNPs. The highest level of <i>p</i>-coumaric acid was obtained under EF (34.27% compared to control). At 25% FC, EB and FeNPs (1 mg L<sup>−1</sup>) increased the level of caffeic acid in thyme plants by 24.70% and 10.08%, respectively. In addition, inoculation with EB increased (11.9%) the content of ferulic acid in plants and the application of FeNPs as a foliar spray decreased the level of ferulic acid in thyme plants. The highest essential oil percentage at 25% FC was observed after inoculation with EF and FeNPs (0.5 mg L<sup>−1</sup>), resulting in significant increases of 14.7% and 82.12%, respectively, compared to the control. A decrease in irrigation level led to an increase in the percentage of essential oil in thyme plants while decreasing dominant essential oil compounds, thymol, and carvacrol. The levels of thymol and carvacrol in the essential oil were not affected by the interaction effects of drought stress, endophytes, and FeNPs. EF and FeNPs (1.5 mg L<sup>−1</sup>), respectively, caused significant increases of 17.44% and 29.87% compared to the control in the amount of thymol and significant increases of 13.75% and 31.01% in the amount of carvacrol. All FeNPs concentrations decreased the concentrations of ferulic acid, FeNPs (1.5 mg L<sup>−1</sup>) and PPO; these particles act as abiotic stressors at sub-toxic levels and become phytotoxic at higher concentrations.</p><h3>Conclusions</h3><p>It seems that combining endophytes with FeNPs showed promise in enhancing drought tolerance in <i>T. vulgaris</i>. These treatments have significantly contributed to the production of enzymatic antioxidants, flavonoids, and phenolic compounds, leading to a reduction in the amounts of oxidants. At the same time, they have improved both the quality and quantity of essential oils. This highlights the importance of establishing an effective antioxidant system in response to environmental stresses.</p><h3>Graphical Abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":512,"journal":{"name":"Chemical and Biological Technologies in Agriculture","volume":null,"pages":null},"PeriodicalIF":5.2000,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chembioagro.springeropen.com/counter/pdf/10.1186/s40538-024-00682-x","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical and Biological Technologies in Agriculture","FirstCategoryId":"97","ListUrlMain":"https://link.springer.com/article/10.1186/s40538-024-00682-x","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AGRICULTURE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Background
As climate change and water scarcity increasingly threaten agricultural productivity, enhancing plant resilience to drought has attracted great attention. This study explored the potential of combining Fe2O3 nanoparticles (FeNPs), endophytic bacteria (EB), and endophytic fungi (EF) to boost drought tolerance in Thymus vulgaris. The research aimed to assess how these combined treatments affect the plant’s physiological responses and chemical composition under drought stress.
Results
A factorial experiment was designed using completely randomized design (CRD) method, incorporating four irrigation levels [100%, 75%, 50%, and 25% field capacity (FC)], four FeNPs concentrations (0, 0.5, 1, and 1.5 mg L−1), and three endophyte types (control, bacteria, and fungi). After extracting, purifying, identifying, and screening EB and EF from nine Lamiaceae species, the endophytes Azospirillum lipoferum and Aspergillus oryzae isolated from Salvia mirzayanii exhibited the highest drought resistance. The highest amounts of TFM (45.45 g) and TDM (21.56 g) were obtained using the combination of EB and FeNPs at 1 mg L−1 under irrigation with 100% FC. At 25% FC, EB treatment increased the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) by 62.12% and 18.23% compared to the control, respectively. In addition, under optimal humidity conditions, FeNP concentrations were higher than 0.5 mg L−1 leading to a decrease in PPO activity. At 25% FC, the highest content of total phenols was observed with a 37.5% increase under EB treatment using 1 mg L−1 of FeNPs, while the highest content of total flavonoids showed a 62.72% increase under EF treatment with 0.5 mg/L of FeNPs. The highest level of p-coumaric acid was obtained under EF (34.27% compared to control). At 25% FC, EB and FeNPs (1 mg L−1) increased the level of caffeic acid in thyme plants by 24.70% and 10.08%, respectively. In addition, inoculation with EB increased (11.9%) the content of ferulic acid in plants and the application of FeNPs as a foliar spray decreased the level of ferulic acid in thyme plants. The highest essential oil percentage at 25% FC was observed after inoculation with EF and FeNPs (0.5 mg L−1), resulting in significant increases of 14.7% and 82.12%, respectively, compared to the control. A decrease in irrigation level led to an increase in the percentage of essential oil in thyme plants while decreasing dominant essential oil compounds, thymol, and carvacrol. The levels of thymol and carvacrol in the essential oil were not affected by the interaction effects of drought stress, endophytes, and FeNPs. EF and FeNPs (1.5 mg L−1), respectively, caused significant increases of 17.44% and 29.87% compared to the control in the amount of thymol and significant increases of 13.75% and 31.01% in the amount of carvacrol. All FeNPs concentrations decreased the concentrations of ferulic acid, FeNPs (1.5 mg L−1) and PPO; these particles act as abiotic stressors at sub-toxic levels and become phytotoxic at higher concentrations.
Conclusions
It seems that combining endophytes with FeNPs showed promise in enhancing drought tolerance in T. vulgaris. These treatments have significantly contributed to the production of enzymatic antioxidants, flavonoids, and phenolic compounds, leading to a reduction in the amounts of oxidants. At the same time, they have improved both the quality and quantity of essential oils. This highlights the importance of establishing an effective antioxidant system in response to environmental stresses.
期刊介绍:
Chemical and Biological Technologies in Agriculture is an international, interdisciplinary, peer-reviewed forum for the advancement and application to all fields of agriculture of modern chemical, biochemical and molecular technologies. The scope of this journal includes chemical and biochemical processes aimed to increase sustainable agricultural and food production, the evaluation of quality and origin of raw primary products and their transformation into foods and chemicals, as well as environmental monitoring and remediation. Of special interest are the effects of chemical and biochemical technologies, also at the nano and supramolecular scale, on the relationships between soil, plants, microorganisms and their environment, with the help of modern bioinformatics. Another special focus is the use of modern bioorganic and biological chemistry to develop new technologies for plant nutrition and bio-stimulation, advancement of biorefineries from biomasses, safe and traceable food products, carbon storage in soil and plants and restoration of contaminated soils to agriculture.
This journal presents the first opportunity to bring together researchers from a wide number of disciplines within the agricultural chemical and biological sciences, from both industry and academia. The principle aim of Chemical and Biological Technologies in Agriculture is to allow the exchange of the most advanced chemical and biochemical knowledge to develop technologies which address one of the most pressing challenges of our times - sustaining a growing world population.
Chemical and Biological Technologies in Agriculture publishes original research articles, short letters and invited reviews. Articles from scientists in industry, academia as well as private research institutes, non-governmental and environmental organizations are encouraged.