Impact of Beneficial Microorganisms on Strawberry Growth, Fruit Production, Nutritional Quality, and Volatilome

Abstract

Arbuscular mycorrhizal fungi (AMF) colonize the roots of most terrestrial plant species, improving plant growth, nutrient uptake and biotic/abiotic stress resistance and tolerance. Similarly, plant growth promoting bacteria (PGPB) enhance plant fitness and production. In this study, three different AMF (Funneliformis mosseae, Septoglomus viscosum, and Rhizophagus irregularis) were used in combination with three different strains of Pseudomonas sp. (19Fv1t, 5Vm1K and Pf4) to inoculate plantlets of Fragaria × ananassa var. Eliana F1. The effects of the different fungus/bacterium combinations were assessed on plant growth parameters, fruit production and quality, including health-promoting compounds. Inoculated and uninoculated plants were maintained in a greenhouse for 4 months and irrigated with a nutrient solution at two different phosphate levels. The number of flowers and fruits were recorded weekly. At harvest, fresh and dry weights of roots and shoots, mycorrhizal colonization and concentration of leaf photosynthetic pigments were measured in each plant. The following fruit parameters were recorded: pH, titratable acids, concentration of organic acids, soluble sugars, ascorbic acids, and anthocyanidins; volatile and elemental composition were also evaluated. Data were statistically analyzed by ANOVA and PCA/PCA-DA. Mycorrhizal colonization was higher in plants inoculated with R. irregularis, followed by F. mosseae and S. viscosum. In general, AMF mostly affected the parameters associated with the vegetative portion of the plant, while PGPB were especially relevant for fruit yield and quality. The plant physiological status was differentially affected by inoculations, resulting in enhanced root and shoot biomass. Inoculation with Pf4 bacterial strain increased flower and fruit production per plant and malic acid content in fruits, while decreased the pH value, regardless of the used fungus. Inoculations affected fruit nutritional quality, increasing sugar and anthocyanin concentrations, and modulated pH, malic acid, volatile compounds and elements. In the present study, we show for the first time that strawberry fruit concentration of some elements and/or volatiles can be affected by the presence of specific beneficial soil microorganisms. In addition, our results indicated that it is possible to select the best plant-microorganism combination for field applications, and improving fruit production and quality, also in terms of health promoting properties.

Comparative study of plant growth‐promoting bacteria on the physiology, growth and fruit quality of strawberry

“…Leaf pigments can be regarded as an indicator parameter of plant health. The absence of effect of PGPB inoculation on leaf chlorophyll and carotenoids was also observed in Todeschini et al ., suggesting that PGPB inoculation did not affect chloroplast development in strawberry plants.…”

“…CC1, Bacillus safensis B106 and Bacillus subtilis B167A) were evaluated for their possible beneficial effect with regard on the physiology, growth and fruit production of strawberry plants under controlled conditions. According to most of the studies conducted on strawberry plants, PGPB have shown a positive effect on their growth and development . However, in this study, no beneficial effect on plant growth (expressed as plant height and number of leaves) was observed since all plants presented no visual or very small changes in their size.…”

“…This finding could be related to the production of growth hormones such as indole‐3‐acetic acid, typical of such endophytic bacteria . Rahman et al ., Todeschini et al . and Bona et al .…”

The Effects of a Microorganisms-Based Commercial Product on the Morphological, Biochemical and Yield of Tomato Plants under Two Different Water Regimes

“…For the rest of the cultivars, no significant differences were seen between the number of the fruits of inoculated and uninoculated plants, even though for most of the inoculated plants the registered number of fruits was bigger than that of the uninoculated tomato plants. Positive effects of the AMF-bacteria inoculation on the number of fruits have also been observed by Todeschini et al, 2018 [31] in strawberries or by Bona et al, 2017 [32] in tomatoes.…”

Trading on the arbuscular mycorrhiza market: from arbuscules to common mycorrhizal networks

“…The same authors highlighted a positive effect of Agrobacterium radiobacter on root colonization. Todeschini et al (2018) recently reported an impact of PGPR and AMF co-inoculation on strawberry quality as well as the importance of the strains. Despite huge progress in the New Phytologist (2019)…”