Submitted to: Journal of Food Agriculture and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2014
Publication Date: 1/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61009
Citation: Malik, N.S., Nunez, A., Mckeever, L. 2015. Mycorrhizal symbiosis in leeks increases plant growth under low phosphorus and affects the levels of specific flavonoid glycosides. Journal of Food Agriculture and Environment. 13(1):54-60.
Interpretive Summary: Soil Fungi known as mycorrhizae benefit plant growth and development, as well as the quality of the produce, by increasing uptake of nutrients from the soil, especially soils deficient in phosphorus. In addition, mycorrhizal infections could increase resistance in plants to diseases or pathogens. One mechanism to enhance résistance to diseases is perhaps through the induction of increased levels of polyphenols such as phytoalexins and/or flavonoids. Polyphenols, including flavonoids, are also well known as health benefiting compounds for various human ailments (e.g., anti-cancer, antiviral, anti-inflammatory effects and protection against cardiovascular diseases). This study was conducted to evaluate the effects of mycorrhizal symbiosis on plant leeks growth and polyphenol and/or flavonoid levels. Our results showed increased plant growth with mycorrhizal symbiosis under limited Phosphorus levels. In addition, our results showed increased levels of different flavonoid glycosides, thus suggesting improvements in the quality of produce along with higher production.
Technical Abstract: Introduction- Mycorrhizae symbiosis is a universal phenomenon in nature that promotes plant growth and food quality in most plants, especially, under phosphorus deficiency and water stress. Objective- The objective of this study was to assess the effects of mycorrhizal symbiosis on changes in the levels of polyphenols and/or flavonoids in leeks that could affect the quality of the produce. Methods- Methanaloic extracts of the plants were produced based on our previously established methods and polyphenols/flavonoids were analyzed by UHPLC/UV-MS to quantify the individual flavonoids. To identify the flavonoids under the specific peaks, mass spectrometry analysis was performed using a high resolution quadrupole-time of flight mass spectrometer with electrospray ionization (ESI) in the positive mode. Results- The experiments showed increased growth of the leaks, as measured by height and mass of the plant, in association with mycorrhizae at low P in the nutrient solution. In addition, different glycosides of kaempferol showed significant increases in mycorrhizal plant and the levels of a few decreased relative to non-mycorrhizal controls. Conclusions- Symbiosis of leeks with Glomus intraradices mycorrhizae improved growth and quality of the produce by increasing the levels of specific flavonoid glycosides.