In Vivo Endophytic, Rhizospheric and Epiphytic Colonization of Vitis vinifera by the Plant-Growth Promoting and Antifungal Strain Pseudomonas protegens MP12

Abstract

An evaluation was conducted of the colonization of Pseudomonas protegens MP12, a plant-growth promoting and antagonistic strain, inoculated in vine plants during a standard process of grapevine nursery propagation. Three in vivo inoculation protocols (endophytic, rhizospheric, and epiphytic) were implemented and monitored by means of both culture-dependent and independent techniques. Endophytic treatment resulted in the colonization of the bacterium inside the vine cuttings, which spread to young leaves during the forcing period. Microscopy analysis performed on transformed dsRed-tagged P. protegens MP12 cells confirmed the bacterium’s ability to penetrate the inner part of the roots. However, endophytic MP12 strain was no longer detected once the plant materials had been placed in the vine nursery field. The bacterium also displayed an ability to colonize the rhizosphere and, when the plants were uprooted at the end of the vegetative season, its persistence was confirmed. Epiphytic inoculation, performed by foliar spraying of cell suspension, was effective in controlling artificially-induced Botrytis cinerea infection in detached leaves. The success of rhizospheric and leaf colonization in vine plants suggests potential for the future exploitation of P. protegens MP12 as biofertilizer and biopesticide. Further investigation is required into the stability of the bacterium’s colonization of vine plants under real-world conditions in vineyards.

Identification and Characterization of Beneficial Soil Microbial Strains for the Formulation of Biofertilizers Based on Native Plant Growth-Promoting Microorganisms Isolated from Northern Mexico

“…Identifying microbial species is very relevant because the beneficial activity is characteristic of certain species [ 14 ]. Bacterial species found in this work belonging to the genera Enterobacter , Pantoea , Pseudomonas , and Serratia have been successfully studied as PGPM in several crops [ 4 , 5 , 8 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. In the case of Pseudomonas allii , it has also been reported as a plant pathogen responsible for soft rot in onions [ 50 ]; even though the plants in this study did not show disease symptoms, further experiments must be performed at later stages of plant development to determine their safety.…”

Biotization of Endophytes Trichoderma asperellum and Bacillus subtilis in Mentha spicata Microplants to Promote Growth, Pathogen Tolerance and Specialized Plant Metabolites

“…Research on the biological control of Rhizoctonia solani on Mentha piperita showed that Pseudomonas fluorescens had the highest in vitro inhibition of the pathogen and was effective in reducing the disease under greenhouse conditions (23%), although T. viride and B. subtilis also reduced the incidence to 50% [ 21 ]. The main concern with the use of soil-applied biological control agents is the colonization and persistence of the microbial inoculum in plants due to abiotic factors such as temperature, humidity, soil conditions or biotic factors such as antagonism, competition, predation, among others that may reduce their efficacy under field conditions [ 22 , 23 ].…”

Biostimulants in Viticulture: A Sustainable Approach against Biotic and Abiotic Stresses

“…During a standard process of grapevine nursery propagation, epiphytic and rhizospheric inoculation by the PGPR strain Pseudomonas protegens MP12 was effective in controlling an artificially induced Botrytis cinerea infection in detached leaves. The success of rhizospheric and leaf colonization in vine plants suggests a potential for the future exploitation of P. protegens MP12 as a biofertilizer and biopesticide [221].…”