Identification and characterization of endophytic bacteria isolated from in vitro cultures of peach and pear rootstocks

Abstract

Endophytes are microorganisms which live symbiotically with almost all varieties of plant and in turn helping the plant in a number of ways. Instead of satisfactory surface sterilization approaches, repeatedly occurring bacterial growth on in vitro rootstock cultures of peach and pear was identified and isolated as endophytic bacteria in our present study. Five different isolates from peach rootstocks were molecularly identified by 16S rRNA gene sequencing as Brevundimonas diminuta, Leifsonia shinshuensis, Sphingomonas parapaucimobilis Brevundimonas vesicularis, Agrobacterium tumefaciens while two endophytic isolates of pear were identified as Pseudoxanthomonas mexicana, and Stenotrophomonas rhizophilia. Identified endophytes were also screened for their potential of plant growth promotion according to indoleacetic acid (IAA) production, nitrogen fixation, solubilization of phosphate and production of siderophore. All seven endophytic isolates have shown positive results for IAA, nitrogen fixation and phosphate solubilization tests. However, two out of seven isolates showed positive results for siderophore production. On the basis of these growth promoting competences, isolated endophytes can be presumed to have significant influence on the growth of host plants. Future studies required to determine the antimicrobial susceptibility profile and potential application of these isolates in biological control, microbial biofertilizers and degradative enzyme production.

Isolation and characterization of plant growth promoting endophytic bacteria isolated from Vigna radiata

“…Similarly, Rajendran et al (2008) isolated three endophytic bacteria from root nodules of Cajanus cajan and two out of three isolates were reported to produce siderophore. Liaqat et al (2016) also reported siderophore production by only 2 out of 7 endophytic bacteria isolated from peach rootstock. IAA values are mean of three replicates ± SD "-" means showed no production "+" means showed low production "++" means moderate production "+++" means high production…”

Agricultural and Other Biotechnological Applications Resulting from Trophic Plant-Endophyte Interactions

“…Under Fe starvation, most microorganisms synthesize siderophores-low-molecular weight iron-chelating agents that solubilize Fe (III) and control intracellular Fe levels [69]. Liaqat and Eltem [70] identified the following species: Brevundimonas diminuta, Leifsonia shinshuensis, Sphingomonas parapaucimobilis, Brevundimonas vesicularis, and Agrobacterium tumefaciens as endophytes that are able to produce siderophores. Earlier, it was evidenced that Methylobacterium phyllosphaerae (isolated from the phyllosphere of lowland rice, India) produced a hydroxamate type of siderophores during Fe starvation, as well as tryptophan and tyrosine [69].…”

Genomic Analysis of Plant-Associated Bacteria and Their Potential in Enhancing Phytoremediation Efficiency

“…To cope with the iron deficiency bacteria utilize siderophores which solubilize and bind Fe 3+ forming siderophore-Fe 3+ complexes that can be taken up by active transport mechanisms. Siderophores produced by endophytic and rhizospheric bacteria may limit bioavailability of iron to the phytopathogens thus constraining their growth [Liaqat and Eltem 2016]. In the genomes of all four plant-associated strains genes responsible for biosynthesis of enterobactin (entABEF), a catechol-type siderophore, were found ( Figure 2) [García et al 2015;Kanehisa et al 2017].…”