Antagonism of plant growth promoting rhizobacteria against the causal agent of the vascular wilting of tomato

Narmer Fernando Galeano Vanegas,Gloria María Restrepo Franco,Beatriz Elena Padilla Hurtado,Javier Guillermo Mantilla Afanador,Nelson Ceballos Aguirre,Sandra Maria Marulanda Moreno

doi:10.15446/rev.colomb.biote.v22n2.79449

Narmer Fernando Galeano Vanegas, Gloria María Restrepo Franco + Show 4 more

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https://doi.org/10.15446/rev.colomb.biote.v22n2.79449

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Abstract

Use of biotechnological potential of native microorganisms as bio-inputs is having a great impact on agricultural systems. Plant Growth Promoting Rhizobacteria (PGPR), in addition to their beneficial effect on plant growth and on the availability of soil elements, also have an antagonistic effect against different pathogens. In this study, growth promotion mechanisms with emphasis on the antagonism of PGPR isolated from sugarcane and tomato crops were evaluated. Antagonism against Fusarium oxysporum f.sp lycopersici (Fol) was determined by dual tests, inhibition of germination and production of chitinases and endoglucanases. 52 isolates were evaluated and according to their results in dual tests 10 were selected for further analysis. Isolate GIBI127 showed the best percentage of Inhibition Germination (IG) of Fol (59.29%). Then, a selection index was calculated using results from gi, dual tests and growth promotion mechanisms to select five best isolates. Finally, these bacteria were evaluated for chitinases and endoglucanases production using Miller´s method. As a result, strain GIBI419 (Burkholderia cepacia) showed a higher production of these enzymes. Selected isolates have antagonistic potential along with plant growth promotion characteristics, which can be used for the development of microbial inoculants which allow the establishment of agricultural systems for tomato cultivation that are sustainable, efficient, and environmentally friendly.

Highlights

The tomato, Solanum lycopersicum L., occupies the first place in the list of world vegetable production of the FAO, with a cultivated area of 4,782,753 ha and a production of 177,042,359 tons (FAOSTAT, 2018)
Dual tests The results of the Inhibitory Efficacy Index (IEI) were mostly less than 70%; the two best isolates were selected for each statistical group of Duncan, taking into account their behavior in the production of indoleacetic acid (IAA) and the acetylene reduction activity (ARA) (Table 1)
As for the Fol fungus, the COMBIA isolate that belonged to the Duncan group with lower IEI was selected; it presented a greater sporulation in comparison with the isolation M3MN (Table 2)

Summary

Introduction

The tomato, Solanum lycopersicum L., occupies the first place in the list of world vegetable production of the FAO, with a cultivated area of 4,782,753 ha and a production of 177,042,359 tons (FAOSTAT, 2018). The records for Colombia indicate that in 2016, 644,642 tons were produced in 16,642 ha of crops (FAOSTAT, 2018). Among the diseases of economic importance in tomato is the vascular wilt, caused by Fusarium oxysporum f. Colombia still does not record data on losses caused by the disease (Vásquez-Ramírez & CastañoZapata, 2017). The control of the disease is carried out by planting resistant cultivars or by using chemical fungicides. These strategies have various limitations such as adaptation of the pathogen to new varieties, deleterious effects of chemical compounds on the beneficial microbiota of the soil, human and animal health, increase in production costs and environmental pollution (Hariprasad et al, 2011)

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