POLYPHASIC CHARACTERIZATION OF Bacillus STRAINS ISOLATED FROM MAIZE

Abstract

The use of bioinoculants with plant growth-promoting bacteria (PGPB) is a sustainable agricultural practice that has been expanding worldwide. Thus, it is fundamental to characterize these bacteria molecularly to provide better security and traceability for bioinoculants production. This work aimed to identify, characterize and develop specific molecular markers for Bacillus strains related to plant-growing promotion. Five strains were identified as B. pumillus (B32), B. thuringiensis (B116), B. megaterium (B119) and B. subitilis (B2082 and B2084) using 16S rRNA gene sequencing and MALDI-TOF mass spectrometry. Repetitive element palindromic (Rep-PCR) and amplified ribosomal DNA restriction analysis (ARDRA) techniques allowed the discrimination of the strains, except B2082 and B2084 that presented identical genetic profiles, indicating that they are same or genetically close isolates. Moreover, specific molecular markers were developed for B116 and B119 strains and may be used for microbial inoculants production quality control, strains traceability and to detail PGPB colonization.

Co-inoculation With Tropical Strains of Azospirillum and Bacillus Is More Efficient Than Single Inoculation for Improving Plant Growth and Nutrient Uptake in Maize.

“…The individual inoculation of Bacillus strains B116 signi cantly increased the sorghum yield and phosphorus grain uptake in the eld (19% and 36%, respectively)(Mattos et al, 2021) and individual inoculation of B2084, increase the millet biomass and P content(Ribeiro et al, 2008). Strain B116, identi ed as B. thuringiensis(Lana et al, 2020), was isolated from the maize rhizosphere, being e cient in bio lm and exopolysaccharide production, and phosphate solubilization(Oliveira et al 2009; Velloso et al 2020). Strain B2084 is an endophytic bacterium isolated from maize leaves and identi ed as B. subtilis by 16S rDNA sequencing(Sousa et al 2021) and by protein pro le using MALDI-TOF mass spectrometry(Lana et al 2020).…”

“…Strain B116, identi ed as B. thuringiensis(Lana et al, 2020), was isolated from the maize rhizosphere, being e cient in bio lm and exopolysaccharide production, and phosphate solubilization(Oliveira et al 2009; Velloso et al 2020). Strain B2084 is an endophytic bacterium isolated from maize leaves and identi ed as B. subtilis by 16S rDNA sequencing(Sousa et al 2021) and by protein pro le using MALDI-TOF mass spectrometry(Lana et al 2020). In addition, the Azospirillum strains (A1626 and A2142) increased maize root surface area in hydroponics(Sousa et al 2018) and show promising results in maize inoculation under eld experiments (unpublished results).…”