The inhibitory effect of tropolone and hinokitiol on the mycelium growth of Phoma narcissi in vitro

Tropolone and hinokitiol (β-thujaplicin) that are present in heartwood of several Cupressaceae trees are known for their antibacterial, antifungal and insecticidal properties. In the present studies it was showed that tropolone and hinokitiol greatly inhibited in vitro, on PDA medium, the mycelium growth of Phoma narcissi, a pathogen of Hippeastrum and other species of family Amaryllidaceae. Total inhibition of the mycelium growth of Phoma narcissi took place at a tropolone concentration of 6.0 µg·cm-3 and at a hinokitiol concentration of 50.0 µg·cm-3. Fungicidal doses of tropolone and hinokitiol for the mycelium growth of Phoma narcissi were also documented. The results presented in this paper are discussed with data available in literature on the antifungal action of tropolone and hinokitiol on other species of pathogenic fungi

The effect of Medicago arabica, M. hybrida and M. sativa saponins on the growth and development of Fusarium oxysporum Schlecht f. sp. tulipae apt.

In the present work it was shown that total saponins originated from M. hybrida and M. sativa substantially limited mycelium growth of F. oxysporum f. sp. tulipae and symptoms of fusariosis on tulip bulbs. Out of 15 individual tested saponins originated from M. arabica, M. hybrida and M. sativa, four compounds: 3-O-[β-D-glucopyranosyl (1→2)α-L-arabinopyranosyl] hederagenin, hederagenin 3-O-β-D-glucopyranoside, medicagenic acid, medicagenic acid 3-O-β-D-glucopyranoside had the strongest inhibitory effect on mycelium growth of Fusarium oxysporum f. sp. tulipae on PDA medium. The total saponins from M. arabica, M. hybrida and M. sativa inhibited the number of colony forming units of Fusarium oxysporum f. sp. tulipae in artificially infested substrate. The use of saponins originated from Medicago as a fungicide is suggested

Influence of Bacillus polymyxa on the growth and development of Fusarium oxysporum f. sp. tulipae

Antagonistic effect of Bacillus polymyxa, strain S13, toward Fusarium oxysporum f. sp. tulipae was evaluated iii vitro and in vivo. The growth of the pathogen was greatly inhibited in dual cultures with Bacillus polymyxa on potato dextrose agar. Suspension of B. polymyxa and its filtrate substantially inhibited spore germination and development of Fusarium oxysporuum f. sp. tulipae on tulip bulbs

The effect of chitosan on limitation of growth and development of some pathogenic fungi for ornamental plants

The inhibitory effect of crab-shell chitosan, medium (200-800 cps) and high molecular weight ( 800-2000 cps) (purchased from Sigma-Aldrich Chemicals) toward Alternaria alternata, Botrytis tulipae, Fiisarium oxysporum f. sp. callistephi, Fusarium oxysporum f. sp. tulipae, Phoma narcissi and Phoma poolensis was evaluated in vitro and in vivo. The chitosan evidently inhibited in vitro growth of all tested pathogens, with a marked effect at higher concentrations above 200 μg/cm3. Chitosan at a concentration of 1,25; 2,5 and 5,0 mg/cm3 didn't have inhibitory action in appearance of fungi growth on naturally contaminated Callistephus chinensis seeds. At the same concentrations, chitosan applied as bulb scales dressing of Hymenocallis narcissiflora bulbs, before inoculation or after inoculation with Phoma narcissi, inhibited the development of necrotic spots on scales. Chitosan used preventively or curatively at a concentrations of 1,25; 2,5 and 5,0 mg/cm3 indicated inhibitory effect on development of Fusarium oxysporum f. sp. tulipae on tulip bulbs. Chitosan at a concentration of 10 mg/cm3 applied preventively (first spray 12th June) was very effective in the control of Puccinia antirrhini on snapdragon in the field. The strongest inhibitory effect was observed on snapdragon treated 8 times at week intervals

Anti-pathogenic properties of plant peptide hormone phytosulfokines (PSK's)... Pestycydy

Abstract: Phytosulfokine-α (PSK-α) (H-Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln-OH) (I), a sulfated growth factor universally found in both monocotyledons and dicotyledons, strongly promotes proliferation of plant cells in culture. The C-terminal truncated analog named PSK-β (Tyr(SO3H)-Ile-Tyr(SO3H)-Thr) (II) showed a 10-fold lower activity than that of the parent pentapeptide. Because PSK-α promotes proliferation and differentiation during the plant growth we undertook the studies on the influence of PSK-α on plant defense mechanisms in that period. In present studies on PSK-α (I), PSK-β (II), and its analogues, we performed a search of another biological properties. The aim of our investigation was evaluation of PSK-α, PSK-β and their selected analogues in relation to growth and development of plant pathogens, such as Phoma narcissi and Botrytis tulipae. In these studies we elaborated the synthesis of PSK-α or PSK-β and their 22 analogues modified by natural and non-natural amino acid residues. Peptides were synthesized by the solid phase method according to the Fmoc procedure on a Wang-resin. Free peptides were released from the resin by 95% TFA in the presence of EDT. Biological effect of these peptides was evaluated by test on the growth and development of pathogens of P. narcissi and B. tulipae