Beauveria bassiana Multifunction as an Endophyte: Growth Promotion and Biologic Control of Trialeurodes vaporariorum, (Westwood) (Hemiptera: Aleyrodidae) in Tomato.

Lorena Barra-Bucarei,Gonzalo Silva Aguayo,Matías Guerra Peñalosa,Macarena Gerding González,Andrés France Iglesias,Pedro Vergara Vera

doi:10.3390/insects11090591

Abstract

Simple SummaryThe tomato, Solanum lycopersicum L. has great importance worldwide for its nutritional characteristics and its antioxidant content. It is cultivated in different geographical areas, under field and greenhouse conditions, and it can be subjected to abiotic and abiotic factors that negatively affect production and quality. In this study, we evaluated the effect of five native endophytic strains of Beauveria bassiana on the reproduction of greenhouse whiteflies and the growth of tomatoes. The endophyte was inoculated in the substrate, and plants were afterward exposed to adult populations of the insect. For plant-growth promoter activity, the effect of endophytic strains on phosphate solubilization, iron siderophores production, plant height, and biomass was determined. The RGM-557 strain reduced the number of eggs and nymphs per cm2 on leaflet by 66 and 65%, respectively, compared with the control (water); while in comparison with the chemical insecticide the reduction was 32 and 55%, respectively. Most strains showed some degree of phosphate solubilization and siderophores production. Plants inoculated with strains RGM-557 and RGM-731 produced the greatest plant heights; RGM-731 obtained the greatest plant biomass. Endophytic B. bassiana provide important protection levels against whiteflies in tomato—in addition to promoting their growth.The tomato, Solanum lycopersicum L. is one of the most consumed vegetables in the world; nevertheless, it is affected by biotic and abiotic factors that reduce its productivity. The whitefly is globally considered as the main pest under protected crop conditions, where biologic control using endophytic fungi emerges as a sustainable alternative. We evaluated the indirect effects of five native endophytic strains of Beauveria bassiana on the reproduction of greenhouse whiteflies and the growth of tomatoes. The plant growth substrate was inoculated with five strains of this endophyte and the resulting plants were then exposed to whiteflies afterwards. The effect that endophytic strains had on phosphate solubilization, iron siderophore production, plant height, and plant biomass were evaluated. The evaluated endophytes reduced the number of eggs per cm2 on leaflets compared to the control and behaved similarly to the commercial synthetic insecticide. Leaflets inoculated with strains RGM-557, RGM-644 and RGM-731 showed fewer nymphs than the control and those treated with insecticide. RGM-557 and RGM-731 produced the greatest plant heights; RGM-731 obtained the greatest plant biomass. Our study provides evidence that native endophytic strains of B. bassiana have a biocontrol effect on whiteflies and could be used to promote tomato growth.

Highlights

The tomato, Solanum lycopersicum L. is one of the most cultivated vegetables worldwide due to its low-fat content and excellent source of dietary fiber, minerals, vitamins and antioxidants [1]
Previous evidence has shown that B. bassiana can control greenhouse whitefly (GWF), this research is novel because it provides further details regarding the effects this fungus has as an endophyte against this pest [10,12]
We demonstrated that the endophytic strains achieved a significant decrease in the number of eggs and nymphs in comparison to the uninoculated control, with strains RGM-557 and RGM-644 showing similar effects to the insecticide in relation to the decreased number of GWF eggs and strains RGM-557, RGM-644 and RGM-731 showing a significantly higher reduction in the number of nymphs compared to the synthetic insecticide

Summary

Introduction

The tomato, Solanum lycopersicum L. is one of the most cultivated vegetables worldwide due to its low-fat content and excellent source of dietary fiber, minerals, vitamins and antioxidants [1]. It can be consumed fresh and/or processed into a wide variety of manufactured products [2]. Plant development can be negatively affected by biotic and abiotic factors, provoking decreased yields [3]. Several pests negatively affect tomato production; the greenhouse whitefly (GWF). The damage produced consists of perforating plant tissues and sucking the sap directly from the vascular bundles—which leads to a decrease in photosynthetic activity, reduced vigor and loss of fruit quality (indirect damage) due to the presence of sooty mold [4]

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