Eclipta prostrata (L.) is an important and well-known medicinal plant due to its valuable bioactive compounds. Microorganisms, including arbuscular mycorrhizal fungi (AMF), and salinity could directly impact plant metabolome, thus influencing their secondary metabolites and the efficacy of herbal medicine. In this study, the role of different single AMF species (Funneliformis mosseae, Septoglomus deserticola, Acaulospora lacunosa) and a mixture of six AMF species in plant growth and physio-biochemical characteristics of E. prostrata under non-saline conditions was investigated. Next, the most suitable AM treatment was chosen to examine the impact of AMF on physio-biochemical features and polyphenol profiles of E. prostrata under saline conditions (100 and 200 mM NaCl). The findings indicated that AMF mixture application resulted in more effective promotion on the aboveground part of non-saline plants than single AMF species. AM mixture application improved growth and salt tolerance of E. prostrata through increasing the activity of catalase, peroxidase (at 4 weeks), proline, and total phenolic content (at 8 weeks). Such benefits were not observed under high salinity, except for a higher total phenolic concentration in mycorrhizal plants at 8 weeks. Through high-performance liquid chromatography, 14 individual phenolic compounds were analyzed, with wedelolactone and/or 4,5-dicaffeoylquinic acid abundant in all treatments. Salinity and mycorrhizal inoculation sharply altered the polyphenol profiles of E. prostrata. Moderate salinity boosted phenolic compound production in non-AM plants at 4 weeks, while at 8 weeks, the decline in the content of phenolic compounds occurred in uncolonized plants subjected to both saline conditions. Mycorrhization augmented polyphenol concentration and yield under non-saline and saline conditions, depending on the growth stages and salt stress severity. Plant age influenced polyphenol profiles with usually a higher content of phenolic compounds in older plants and changed the production of individual polyphenols of both non-AM and AM plants under non-stress and salt stress conditions. A better understanding of factors (involving mycorrhiza and salinity) affecting the phenolic compounds of E. prostrata facilitates the optimization of individual polyphenol production in this medicinal plant.

The aim of this study was to determine the influence of mycorrhizal inoculation and sand-peat composition as growth substrate on the biomass, and individual polyphenol concentration of Eclipta prostrata. Mycorrhizal inoculation alters some secondary metabolites of E. prostrata, showing significant differences in polyphenol contents between the treatments. Moreover, varying peat and sand rates, representing different nutrient supplies, had significant impacts on both mycorrhizal colonization and growth responses. Our results highlight that 60/40% (v/v) sand and peat ration is the best for a large-scale cultivation of E. prostrata, moreover supporting the highest total phenolic content. Through high-performance liquid chromatography (HPLC) analysis, nine individual phenolic components were analyzed, including wedelolactone and demethyl-wedelolactone at the highest concentration. Some of the identified compounds, such as 5-o-caffeoylquinic acid, quercetin-3-arabinoside, 4-o-caffeoylquinic acid, and protocatechuic acid have not been reported previously in E. prostrata cultivars. Using hierarchical cluster analysis, multiple groups are represented, suggesting the role of mycorrhizal inoculation, growth substrate, and their interaction on secondary metabolites of E. prostrata. Better understanding of the phenolic composition of E. prostrata and factors influencing it help to identify new industrial applications of this medicinal plant (together with arbuscular mycorrhizal fungi), and moreover, help to develop new strategies for the prevention and treatment of different diseases.

Consumption of chili peppers (Capsicum frutescens L.) represents an important aspect of the daily diet for Vietnamese population because of its high content for antioxidant compounds. To increase the economic benefits related to chili peppers cultivation and reduce negative impacts of the high input agriculture on the environment, biological alternatives to chemical fertilizers are strongly demanded. Arbuscular mycorrhizal fungi (AMF) are well-known soil microorganisms of great interest for their potential application in agriculture as 'bioenhancers' of plant performance. However selection of suitable AMF strains is time-costing and the outcome of field inoculation can be affected by the weak ability to compete among the native AMF population. In the present study we proposed a "bulk" approach to identify soil hosting AMF strains suitable for the development of inocula for C. frutescens. Three different soils were tested as source of AMF inoculum in bi-compartmented pot cultures. All the inoculated treatments performed significantly better, in terms of plant growth, compared with the noninoculated control plants. Pots inoculated with soil from tropical forest showed the best growth performances. Molecular characterization of the AMF root assemblages highlighted differences in the composition among treatments, with the "tropical forest soil" treatment characterized by the highest number of AMF taxa colonizing the roots.

Book -18 th Alps-Adria Scientific Workshop