Epiphytic Microbial Community and Post-Harvest Characteristics of Strawberry Fruits as Affected by Plant Nutritional Regime with Silicon

Fabio Valentinuzzi,Tanja Mimmo,Youry Pii,Edoardo Puglisi,Marco Trevisan,Luigimaria Borruso,Stefano Cesco

doi:10.3390/agronomy11122407

Abstract

Despite being not essential to plants, Silicon (Si) has proven to have promoting effects on plants growth, yield, and resistance against biotic and abiotic stressors. The increase of concentration in specific minerals in plant tissues can also improve shelf-life, which, in fruits like strawberries, is also affected by the epiphytic microbial community. The present research was carried out to assess whether Si biofortification of strawberry plants, grown in soilless system, could affect plants yield and post-harvest feature of fruits during the storage period, carried out at three different temperatures (i.e., 1, 4 and 10 °C) for 7 and 14 days. Furthermore, we investigated whether the plant nutritional regime, specifically the Si fertilization, can impact the composition of microbial community. Our results showed that biofortification did not significantly affect fruits firmness, whereas, at the highest Si levels, an increase in titratable acidity was observed. The microbial community analysis highlighted for the first time the presence of probiotic bacteria, as Bacillus breve, which could present interesting technological features as strains adapted to the strawberry fruit-sphere. In addition, with the increasing levels of Si biofortification, the depletion of potentially pathogenic microorganisms, like Escherichia coli and Terrisporobacter glycolicus, was also observed. In conclusion, data here reported highlight for the first time the possible role played by the nutritional regimes of strawberry plants in shaping composition of the fruit epiphytic microbial community.

Highlights

Mineral malnutrition, known as ‘hidden hunger’, is a phenomenon affecting two-thirds of the world’s population, both in industrialized and developing countries and having strong impact on people’s health [1,2,3,4]
Despite being the number of flowers not affected by Si supplementation, the average number of berries produced by each plant show a gradual decrease with the increasing Si concentration
As far as the average yield per plant is concerned, data showed that 50 mg L−1 Si treated plants did not show a significant difference with respect to control plants, whereas the yield decreased significantly in plants treated with the higher concentration of Si (i.e., 100 and 200 mg L−1 )

Summary

Introduction

Known as ‘hidden hunger’, is a phenomenon affecting two-thirds of the world’s population, both in industrialized and developing countries and having strong impact on people’s health [1,2,3,4]. Plants do not require Si to complete their life cycle [12], the inclusion of Si in fertilization programs has shown positive effects on crops, thereby improving the tolerance to biotic and abiotic stressors, enhancing crops yield, and having synergistic effects on the absorption of other mineral elements [12,14,16,17] In this context, several studies have been carried out with the aim of increasing the concentration of Si in the edible organs of plants [18], demonstrating that leafy vegetables [19,20], green bean [21] and strawberry [22] can be good targets for Si fortification. These aspects might be relevant (i) when the objective is represented by modulation of foods nutraceutical properties and (ii) when an extension of the shelf-life is desired

Methods

Results

Discussion

Conclusion