Isolation and screening of multi-trait plant growth-promoting rhizobacteria (PGPR) colonizing saffron (Crocus sativus L.) rhizosphere

Chamkhi, Imane; Sbabou, Laïla; Aurag, Jamal

doi:10.1016/j.bcab.2023.102730

Cited by 6 publications

(1 citation statement)

References 52 publications

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“…Indirect mechanisms involve the production of antimicrobial compounds, induction of systemic resistance, and competition for nutrients in the rhizosphere [ 5 ]. Plant growth-promoting rhizobacteria associated with Crocus sativus L. (saffron) have been extensively explored using cultivation-dependent methods [ 6 – 14 ], and metagenomic approaches [ 15 – 17 ]. However, despite the large number of PGPR strains secluded from saffron plant, few studies have investigated the genomic basis underlying their plant-beneficial activities.…”

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confidence: 99%

Functional analysis and comparative genomics of Rahnella perminowiae S11P1 and Variovorax sp. S12S4, two plant growth-promoting rhizobacteria isolated from Crocus sativus L. (saffron) rhizosphere

ZOUAGUI,

AURAG

et al. 2024

BMC Genomics

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Background Rahnella perminowiae S11P1 and Variovorax sp. S12S4 are two plant growth-promoting rhizobacteria that were previously isolated from the rhizosphere of Crocus sativus L. (saffron), and have demonstrated interesting PGP activities and promising results when used as inoculants in field trials. To further elucidate the molecular mechanisms underlying their beneficial effects on plant growth, comprehensive genome mining of S11P1 and S12S4 and comparative genomic analysis with closely related strains were conducted. Results Functional annotation of the two strains predicted a large number of genes involved in auxin and siderophore production, nitrogen fixation, sulfur metabolism, organic acid biosynthesis, pyrroloquinoline quinone production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, volatile organic compounds production, and polyamine biosynthesis. In addition, numerous genes implicated in plant-bacteria interactions, such as those involved in chemotaxis and quorum sensing, were predicted. Moreover, the two strains carried genes involved in bacterial fitness under abiotic stress conditions. Comparative genomic analysis revealed an open pan-genomic structure for the two strains. COG annotation showed that higher fractions of core and accessory genes were involved in the metabolism and transport of carbohydrates and amino acids, suggesting the metabolic versatility of the two strains as effective rhizosphere colonizers. Furthermore, this study reports the first comparison of Multilocus sequence analysis (MLSA) and core-based phylogenies of the Rahnella and Variovorax genera. Conclusions The present study unveils the molecular mechanisms underlying plant growth promotion and biocontrol activity of S11P1 and S12S4, and provides a basis for their further biotechnological application in agriculture.

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