In vitro and in vivo effects of Pseudomonas spp. and Bacillus sp. on Fusarium acuminatum, Botrytis cinerea and Aspergillus niger infecting Cucumber

Abstract

SummaryCucumber (Cucumis sativus L) is an important member of the Cucurbitaceae family. Production of healthy nursery is necessary for high-quality production of this crop in greenhouses and in fields. With the idea of minimizing the use of pesticides and mineral fertilizers to preserve soil quality, we investigated the effects of plant growth promoting bacteria (PGPB) on growth promotion and protection of cucumber plants from phytopathogenic fungi. The effects of Pseudomonas spp. strains with different antifungal activities and Bacillus sp. Q10 strain with PGP activity were tested on cucumber plants. Antagonistic activity of Pseudomonas spp. against the growth of several phytopathogenic fungi isolated from cucumber: F. acuminatum, B. cinerea and A. niger, was observed. The influences of overnight cultures, supernatants and heat-stable antifungal factors were tested on the phytopathogenic fungi in vitro. Pseudomonas sp. K35 and K24 strains were more effective than P. chlororaphis Q16 and Pseudomonas sp. K27, showing 70-80% of fungal growth inhibition regardless of culture or fraction applied. The good antagonists that belong to pseudomonads and Bacillus sp. Q10 strain were used as mixtures for estimation of plant growth and health promoting effects on cucumber plants. Growth dynamics differed depending on the applied strain of Pseudomonas sp. The M3 treatment (a mixture of Bacillus sp. Q10 and P. chlororaphis Q16) stimulated the initial phase of growth, while M4 (a mixture of Bacillus sp. Q10 and Pseudomonas sp. K24) resulted in the maximal height at the final measurement. Significant differences in leaf and plant weight (M4), and leaf weight (M5, containing K35 strain) were found after the treatments. No significant differences in chlorophyll and NBI level were observed in any of the tested combinations. The obtained results suggested that M3 was suitable for stimulation of the early phase of cucumber growth, while the mixtures M4 and M5 improved plant protection and stimulated the later phases of cucumber growth.

Effect of indigenous Pseudomonas chlororaphis strains on morphological and main chemical growth parameters of basil (Ocimum basilicum L.)

“…The increase in N, P and K content in Ocimum basilicum inoculated with PGPR Pseudomonas putida and Azotobacter chroococcum was previously reported (Ordookhani et al, 2011). In addition, as stated by the other authors (Zdravković et al, 2015), and as it was done in this study, it is suggested that bacterial suspension should be applied during the growth phase of plants when the treatment has the greatest impact, i.e. when enzyme activity is the strongest.…”

“…In this respect, different isolates of fluorescent Pseudomonas species take prominent place. Consequently, these isolates have been intensively studied (Couillerot et al, 2009;Ivanović et al, 2009;Jošić et al, 2012;Jošić et al, 2015;Zdravković et al, 2015;Mrkovački et al, 2016).…”

Isolation and evaluation of Qatari soil rhizobacteria for antagonistic potential against phytopathogens and growth promotion in tomato plants

“…These facts also support the idea that collected rhizobacteria had a stronger effect on B. cinerea compared to F. oxysporum coinciding with the study done in Saudi Arabia as mentioned earlier 41 . In another study by Zdravković et al 60 ., the effects of Pseudomonas spp. and Bacillus sp.…”

Effect of Indigenous Pseudomonas sp. and Bacillus sp. Strains on Yield and Main Chemical Growth Parameters of Radicchio

“…According to Podile and Kishore (2006), PGPR and their interactions with plants are exploited commercially and hold great promise for sustainable agriculture. Applications of these associations have been investigated in maize, wheat, oat, barley, peas, canola, soy, potatoes, tomatoes, lentils, radicchio and cucumber (Gray and Smith, 2005, Jošić et al 2012, Zdravković et al 2015.…”

“…strain Q10 through their effect on the main chemical growth parameters (content of N, P, K, Ca and Mg) and yield of dry biomass of radicchio aerial parts and root. Pseudomonas isolate was selected on the basis of previous studies that confirmed its intrinsic antibiotic resistance and plant growth promoting traits: phosphate solubilization, siderophore and indoleacetic acid production, enzymatic activity (Jošić et al 2012, Jošić et al 2012a, Zdravković et al 2015. In addition, Bacillus sp.…”