Effectiveness of environmentally safe food additives and food supplements in an in vitro growth inhibition of significant Fusarium, Aspergillus and Penicillium species

Abstract

Akköprü A., Özaktan H. (2018): Identification of rhizobacteria that increase yield and plant tolerance to angular leaf spot disease in cucumber. Plant Protect. Sci., 54: 67-73.The biological control of angular leaf spot disease (ALS) of cucumbers (Cucumis sativus), caused by pseudomonas syringae pv. lachrymans (psl), using promising rhizobacteria (RB) and to compare RB efficacy to that of acibenzolar-S-methyl (ASM) was investigated. Effects of ASM and RB isolate pseudomonas putida AA11/1 that was isolated from the healthy cucumber root surface on disease severity and plant growth were evaluated using ALS-susceptible and tolerant cucumber cultivars in a growth chamber and a soilless growing system. ASM and AA11/1 significantly reduced average disease severity of ALS by 69 and 34% in the susceptible cultivar and 92 and 21% in the tolerant cultivar, respectively. ASM treatment significantly reduced psl populations, but AA11/1 did not inhibit psl growth in either cultivar. In the soilless system, disease severity was limited by either ASM or AA11/1, whereas only AA11/1 treatments significantly increased cucumber yield by 68 and 33% in the susceptible and tolerant cultivar, respectively.

The Dominance of Chitosan Hydrochloride over Modern Natural Agents or Basic Substances in Efficacy against Phytophthora infestans, and Its Safety for the Non-Target Model Species Eisenia fetida

“…Some studies mention the more likely indirect secondary effect of chitosan applied to plants, such as the increased resistance of plants thanks to the elicitation of defensive mechanisms in the tissue, together with the mechanical barrier of the polymer chitosan layer [25,26]. However, our abovementioned previous study also confirmed the significant direct in vitro antifungal effect of chitosan [5], which was also experimentally confirmed in the case of P. infestans in this study. The efficacy of chitosan is most probably caused by many mechanisms, such as the electrostatic interaction of positively charged molecules of chitosan with cellular membranes.…”

“…The great antifungal potential of chitosan hydrochloride has already been described in our previous studies [5]. In the specified case, excellent inhibitory values were achieved on model filamentous fungi from the pathogenic and toxicogenic groups Aspergillus, Fusarium, and Penicillium [5]. However, we did not expect such excellent results, particularly against the evolutionarily and biologically different pathogen P. infestans (Oomycetes) [21], mainly due to the complicated biology of this pathogen as well as the very different infectious stages in the process of pathogenesis itself [22].…”

“…The great antifungal potential of chitosan hydrochloride has already been described in our previous studies [5]. In the specified case, excellent inhibitory values were achieved on model filamentous fungi from the pathogenic and toxicogenic groups Aspergillus, Fusarium, and Penicillium [5].…”

“…The reference standard was the synthetic fungicide Luna Experience. The lowest concentration of compound that inhibits 50% of growth compared to the control sets was identified as the MIC50 [5,15,16].…”

“…Chitosan also significantly improves the plant's defense system. In particular, it is mentioned as an elicitor of plant tissue defense mechanisms, including systemic acquired resistance (SAR) to plant pathogens [4][5][6]. Chitosan also has enormous potential in other areas and is also used in the food industry and for biomedicine and pharmaceutical applications due to its non-harmfulness [7][8][9][10].…”