Effect of arbuscular mycorrhizal fungi on the accumulation of secondary metabolites in roots and reproductive organs of Solanum nigrum, Digitaria sanguinalis and Ipomoea purpurea

Nieves Goicoechea,Majid Pouryousef,Ali Reza Yousefi,Sakineh Rashidi

doi:10.1186/s40538-022-00288-1

Abstract

BackgroundThe application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential.Materials and methodsThe objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs of Ipomoea purpurea L., Digitaria sanguinalis L., and Solanum nigrum L. as a problematic weed species.ResultsAmong compared weeds, the roots of D. sanguinalis associated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots of S. nigrum (7.46 mg g−1 FW) following colonization with R. intraradices. Berries of S. nigrum inoculated with R. intraradices had a higher concentration of terpenoids (21.45 mg 100 mL−1 of extract) than reproductive organs of D. sanguinalis and I. purpurea. Colonization with R. intraradices improved total phenolics in seeds of D. sanguinalis compared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves of D. sanguinalis colonized by R. fasciculatum and F. mosseae was 55% and 67%, respectively, higher than I. purpurea plants, grown in the same condition.ConclusionsResults suggest that AMF can play a crucial role in enhancing of secondary metabolites in these three weeds, thereby improving their allelopathic potential and competitive ability.Graphic

Highlights

The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, impacting their allelopathic potential
As the allelochemicals in roots and reproductive organs of I. purpurea, D. sanguinalis and S. nigrum are unknown, the general objective of this study was to evaluate the impact of three AMF (Rhizoglomus intraradices, Rhizoglomus fasciculatum and Funneliformis mosseae), susceptible to establish a symbiotic association with those weeds, on the accumulation of secondary metabolites in roots and reproductive organs of those weed species
Unlike D. sanguinalis, mycorrhizal colonization of S. nigrum and I. purpurea plants with AMF species reached a high percentage (47–70%), making these weeds plants relatively stronger AMF hosts compared to D. sanguinalis

Summary

Introduction

The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, impacting their allelopathic potential. Plants synthesize a broad and diverse assortment of natural products, the great majority of which do not appear to contribute directly in growth and development These compounds have various functions such as in defence against herbivores and pathogens, attracting insects and protecting against UV light [1, 2]. Roth (Convolvulaceae), a troublesome weed of agronomic, horticultural and nursery crops, is often found in cotton, corn, and soybean fields. This weed is prolific, and can produce 8,000 seeds per season [7], which favours the infestation of fields by I. purpurea. Zhou et al [9] identified three chemicals in the root exudates of D. sanguinalis, which may act as allelochemicals interfering with crop growth and affecting soil microbial communities

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