Submitted to: Subtropical Agriculture and Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2016
Publication Date: 12/1/2015
Citation: Malik, N.S., Nunez, A., McKeever, L. 2015. Mycorrhizal symbiosis produces changes in specific flavonoids in leaves of pepper plant (Capsicum annum L.). Subtropical Agriculture and Environments. 66:16-22.
Interpretive Summary: The hyphae of arbuscular mycorrhizae protrude out from the host roots for several inches in the soil and hence provide host plants with extra water (thus combating drought conditions) and nutrients; and thus, help the host plant under poor nutrient availability. Thus, it is well known that mycorrhizal symbiosis could enhance plant growth and productivity generally under poor nutrient and water conditions. However, in our experience most plant microbe interactions result in changes in secondary metabolites; especially polyphenols which host plants produce and use as their defense mechanism. There is also a plethora of literature regarding the health benefits of plant polyphenols. In a previous study, changes were determined in polyphenol levels in leeks after establishing a symbiosis with mycorrhizae fungi, thus improving leek quality for human consumption. To extend those findings, this study was conducted to determine if mycorrhizal symbiosis in pepper plants also increases plant polyphenols. Indeed, this study confirmed that several polyphenols significantly increased in pepper plant leaves as a result of mycorrhizal symbiosis. Thus, the results of this study support earlier hypothesis that in addition to improving yield under poor nutrient and water conditions, mycorrhizal symbiosis can also improve produce quality.
Technical Abstract: In this study, experiments were performed to investigate if mycorrhizal plants grown under optimal growth conditions would improve crop quality compared to the non-mycorrhizal control. The results clearly showed that while mycorrhizal plants grown under an optimal nutrient supply did not increase the growth of the plant, they did improve crop quality as several health benefitting polyphenols were found in greater amounts in mycorrhizal plants compared to controls. Using UHPLC coupled with mass spectrometry, three derivatives of luteolin and 2 derivatives of apigenin were identified, which significantly increased in mycorrhizal plants compared to non-mycorrhizal plants, thus confirming the beneficial effects of mycorrhizal symbiosis even in plants grown under non-stressed conditions.