Biocontrol Potential of Sclerotinia sclerotiorum and Physiological Changes in Soybean in Response to Butia archeri Palm Rhizobacteria.

Luciana Cristina Vitorino,Bárbara Gonçalves Cruvinel,Layara Alexandre Bessa,Fellipe Oliveira da Silva,Edson Luiz Souchie,Márcio Rosa,Fabiano Guimarães Silva

doi:10.3390/plants9010064

Luciana Cristina Vitorino, Bárbara Gonçalves Cruvinel + Show 5 more

Open Access

https://doi.org/10.3390/plants9010064

Copy DOI

Abstract

Sclerotinia sclerotiorum is a necrotrophic parasitic fungus that causes Sclerotinia stem rot (SSR), which is currently one of the most difficult agronomic crop diseases to control. A number of plants of the Brazilian Cerrado biome have been shown to be important sources of symbiotic microorganisms with biotechnological potential, so we decided to test the potential of bacteria isolated from the dwarf jelly palm, Butia archeri (Arecaceae) for the control of the pathogenic effects provoked by S. sclerotiorum. For this, we bioprimed seeds and evaluated the effects of this biopriming on the OJIP transient patterns prior to and following infection by the phytopathogen. Plants treated with the BA48R strain of Enterobacter sp., and in particular, those treated with the BA88R strain of Bacillus cereus presented the best results in terms of the loss/gain of the physiological and symptomatological variables evaluated. The plants bioprimed with BA88R presented high post-infection levels of total chlorophyll (33.35 FCIs) and chlorophyll a (26.39 FCIs), maintained a high Nitrogen Balance Index (NBI = 18.87), and synthesized low concentrations of flavonoids (1.39). These plants also maintained high levels of PIABS (1.111) and PITOTAL (1.300) following infection, and low levels of Di0/RC (0.602), which indicates that, in the presence S. sclerotiorum, the efficiency of the photosynthesis in the plants treated with these bacteria was less affected in the reaction centers, as confirmed by the negative amplitude recorded in the L band. The present study reconfirms the importance of the use of chlorophyll fluorescence for the diagnosis of disease and conditions of stress in crop plants, in addition to demonstrating the effectivenesss of the BA48R bacterial strain and, in particular, the BA88R strain on systemic resistance induction and suppression of S. sclerotiorum in Glycine max plants, with enormous potential for the development of more sustainable agricultural processes.

Highlights

The coexistence of plants and microorganisms in the natural environment has led to the establishment of both negative and positive interactions between different species
No major differences were observed among the treatments in the chlorophyll b indices, the total chlorophyll index followed the same pattern as chlorophyll a, with the highest mean value (FCI = 40.48) being recorded in the BA81R treatment (Table 1)
As observed in the pre-pathogen group, the total chlorophyll followed the same pattern as the chlorophyll a, with the highest indices being recorded in the plants treated with B. cereus strains BA81R and BA88R, Enterobacter sp. strains BA80R and BA110R, BA122R (Bacillus sp.), and the BA123R strain of E. asburiae (Table 1)

Summary

Introduction

The coexistence of plants and microorganisms in the natural environment has led to the establishment of both negative and positive interactions between different species. Plants and microorganisms compete for access to the resources that guarantee their quality of life, which has led to the evolution of countless adaptive strategies, such as the resistance mechanisms in the plants. Plants have an enhanced capacity for the recognition of pathogens, through strategies that involve both conserved elicitors and the characteristics of the pathogens themselves, while pathogens are capable of overcoming physical barriers, suppressing or avoiding immunological mechanisms, and obtaining nutrients from the tissue of the host plant. The plants and microorganisms may both derive advantages from their coexistence. Elicitation of induced systemic resistance (ISR) by rhizospheric bacteria, for example, was initially reported using Pseudomonas spp. Bakker et al [6] explain that the efficacy of these bacteria in biological control lies in combining ISR, through the synthesis of salicylic acid, for example, with direct antibiosis, through the production of siderophores or antimicrobials

Methods

Results

Discussion

Conclusion