Oxalic-acid elicited resistance to Fusarium wilt in Lycopersicon esculentum Mill.

Abstract

Systemic induced resistance (SIR) in a plant enhances disease resistance to a broad spectrum of pathogens. Under climate chamber conditions, oxalic acid's ability to elicit SIR in tomato (Lycopersicon esculentum Mill.) against wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) was tested with a susceptible cultivar (Danish Export). Oxalic acid (OA) was sprayed onto the green part of the tomato plants, at concentrations 2.5, 5, 10, and 20 mM. Two days later, each plant was challenged with 10 ml of Fol suspension (10 6 conidia/ml) inoculated into the soil around the root system. After inoculation, disease incidence (DI) was quantified visually to assess SIR expression. OA-induced resistance (concentration-dependent) by otherwise susceptible tomato plants was obtained.

The effects of salicylic acid, oxalic acid and chitosan on damping-off control and growth in Scots pine in a forest nursery

“…In some forest nurseries, the risk of parasitic damping-off (caused by different species of fungi or oomycetes) is high (Enebak et al 1990, Beyer-Ericson et al 1991, as confirmed by the results of our experiment, where major differences in the number of germinating pine seedlings among different experimental variants were observed. The main reason for the lack of seedling emergence or their death was damping-off, whose symptoms were clearly observed.…”

“…However, better results were obtained with the lower concentration (0.5%). The few studies on OA in the literature were focused on safeguarding rice against Rhizoctonia solani (Jayaraj et al 2010), tomatoes against Fusarium oxysporum (Attitalla & Brishammar 2002) and Norway spruce against bluestain fungus Ceratocystis polonica (Krokene et al 2008). In our study, the effectiveness of OA in protecting pine seedlings from damping-off was relatively limited and at a far lower level compared to CH.…”

“…Similar to SA, the protective effect to OA may depend both on the species to protect and the plant pathogen. The protective mechanisms are also very little-known, though (unlike CH and SA) OA has no antifungal properties (Attitalla & Brishammar 2002). In contrast, Lehner et al (2008) were able to demonstrate the induction of defence-related gene expression due to OA.…”

“…However, a greater efficacy could be achieved at lower concentrations than those used in this study. Indeed, the levels of OA referred to as helpful in the literature vary greatly, from 3 mM in the case of Arabidopsis thaliana against Sclerotium rolfsii, to 20 mM in the case of tomatoes and Fusarium oxysporum (Attitalla & Brishammar 2002, Lehner et al 2008.…”

“…Damping-off of seedlings is a fungal disease capable of generating major losses in forest nurseries. It is caused by pathogens belonging to a range of different systematic groups, including genera Rhizoctonia, Fusarium, Cylindrocarpon, and Phytophthora (Enebak et al 1990, Beyer-Ericson et al 1991. This heterogeneity of origin combines with the emergence of resistance to fungicides to make this disease very hard to combat (Goffeau 2008).…”