Although new studies describe the use of PGPR (Plant Growth-Promoting Rhizobacteria) in Brazil, they rarely evaluate the natural existence of these bacterial species in the soil. The objective of this study was to evaluate PGPR in two samples under different use types, one with native forest and the other with eucalyptus, through construction and sequencing of a metagenomic DNA library. Using specific probes from the internally transcribed region of 16S-23S rRNA genes, fragments of PCR products were inserted into the vector […]

Despite numerous reports on plant growth-promoting rhizobacteria (PGPR), there are few of them explaining their mode of action. It is possible that some plants promote bacterial colonization in the rhizosphere to facilitate plant-bacterium interaction, as if there were a certain mutual specificity. The objective of this study was to verify if lettuce plants promote root colonization by fluorescent pseudomonads, in comparison with other plants and with Bacillus spp. Roots of lettuce and some other vegetables were sampled in different properties […]

Plant growth-promoting rhizobacteria (PGPR) can increase the productivity of several crops, including lettuce. The main objective of this study was to compare the root and/or root collar colonizing ability on the growth promotion ability. A method of evaluation of root colonization was tested with the main objective of speeding up screening trials for growth enhancement of lettuce. Additionally, the antagonism in vitro between rhizobacteria and the pathogen Fusarium sp. was tested to verify if growth promotion ability was determined by […]

Three greenhouse trials were carried out to verify if rhizobacteria can promote citrus plant growth. Ten isolates of fluorescent Pseudomonads, thirteen of Bacillus spp. and seven of other rhizospheric bacteria were tested in three rootstocks seedlings: ‘Cleopatra’ mandarin (Citrus reshni), rangpure lime (Citrus limonia) and Volkamerian lemon (Citrus volkameriana). Depending on the rootstock, seven Pseudomonads, one isolate of Bacillus and one of other rhizospheric bacteria increased the root or shoot dry weight, indicating a high proportion of growth promoters among […]

Rhizobacteria (PGPR) as plant growth boosters can be an option for increased productivity in several crops, including lettuce. Four assays with rhizobacteria isolates from different origins were carried out to verify their potential for growth enhancement in lettuce. Seventy seven fluorescent pseudomonads, 23 Bacillus, and 11 other rhizospheric bacteria isolates were tested in sterilized sand, in sterilized soil, and in a substrate mixture of soil and cattle manure (1:1, in volume), similar to the mixture used by producers, and in […]