Copper tolerance, protein and catalytic activity in phytopathogenic fungus Alternaria alternata

Abstract

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 <p><em>In vitro </em>tolerance of soil borne phytopathogenic fungus i.e. <em>Alternaria alternata </em>in terms of growth, physiology and metal uptake capacity against different doses of copper [Cu(II)] metal was assessed. In preliminary growth experiments, nitrate, chloride and sulphate of Cu(II) were amended in seven different concentrations viz. 25, 50, 75, 80, 85, 90 and 100 ppm in nutritive agar medium along with fungus inoculum. Amongst three salts, the maximum inhibition in radial growth of the fungus was observed with increasing concentrations of copper salts in order of: CuSO<sub>4</sub>> CuNO<sub>3</sub>> CuCl<sub>2</sub>. Further trials were conducted in nutritive broth with four different concentrations (25, 50, 75 and 100 ppm) of copper sulphate to assess growth inhibition, metal accumulation, protein and catalase activity in the fungus biomass. It was found that fungus dry biomass was significantly declined by 70-99% along with net metal accumulation of 40% with increasing metal concentrations. Total protein contents and catalase activity was considerably increased up to 2-5 and 2-3 folds, respectively with increase in metal concentration from 25-100 ppm and incubation period from 48, 72 and 96 hours over control. Present study concludes that <em>A. alternata </em>was able to tolerate up to 90 ppm of copper, therefore it is imperative to consider fungus metal tolerance range during fungicide formulations.</p>
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Enhancing plant defense using rhizobacteria in processing tomatoes: a bioprospecting approach to overcoming Early Blight and Alternaria toxins

“…It is well-established that the overuse of chemicals for plant protection can lead to environmental disturbances, bioaccumulation in food, environmental pollution, harm to beneficial non-target organisms, and the development of fungicideresistant strains of plant pathogens. Although to a much lower extent, the same phenomena have also been observed for copperbased fungicides (Shoaib et al, 2015;Tamm et al, 2022). These downsides highlight the importance of introducing novel and effective broad-spectrum plant protection products to be included in IPM programs, so as to lower the use of fungicides while maximizing sustainability and respecting the environment.…”

Biodegradation of Wood Treated with Copper Based Preservative by Two Dematiaceous Fungi: Alternaria Tenuissima and Ulocladium Consortiale

“…Overall, the results demonstrated that these dematiaceous fungi tolerated quite high concentrations of copper sulphate when compared with other fungi. For example, Shoaib et al [28] reported that Alternaria alternata was able to grow at 90 ppm of CuSO4. The production of melanin by the dematiaceous fungi is considered to be the main mechanism of their tolerance to heavy metals, as it can act in the extracellular precipitation in the adsorption of heavy metals, preventing their action on fungi [29].…”

Fungal and oomycete pathogens and heavy metals: an inglorious couple in the environment

“…alboatrum Verticillium wilt - Growth inhibition (30% decrease) Jaeckel et al ( 2005 ) Oomycetes 0.05–3.0 mM Achlya bisexualis Saprolegniasis in fishes - Decrease in mycelial area and radial extension Lundy et al ( 2001 ) 5 and 12.5 mg/L Phytophthora infestans Late blight - ROS and RNS formation - Increase in protein carbonylation content - Up-regulation of CAT and SOD activities - Nitro-oxidative modifications of proteins and nucleic acids Gajewska et al ( 2020 ) 10–50 µg/ml Saprolegnia delica Coker Saprolegniasis in fishes - Inhibition of sporangia formation - Morphological abnormality ( e.g. thicker and stunted vegetative hyphae, shorter and thicker zoosporangia, low numbers of oogonia and antheridia) Ali ( 2007 ) Cu Fungi 25–100 ppm Alternaria alternata Leaf spot, black spot - Increase in total protein content - CAT activity up-regulation Shoaib et al ( 2015 ) 15 mg·L −1 Alternaria alternata Leaf spot, black spot - Growth inhibition - Damage and deformation of hyphae and conidia - Disorders in the total content of protein, lipids, sugar and n-acetyl glucosamine Ouda ( 2014 ) 10 –4 to 10 –5 M Alternaria solani Early blight - Inhibition of spore germination - Inhibition of germ tube growth Bhajbhuje ( 2013 ) 0.5 mM Aspergillus nige...…”

“…Oxidative stress as a consequence of HM exposure affects white-rot fungus P. chrysosporium (Chen et al 2014 ; Zhang et al 2015 ), A. alternata (Shoaib et al 2015 ), filamentous yeast Trichosporon cutaneum (Lazarova et al 2014 ) , and oomycete P. infestans (Gajewska et al 2020 ). In P. chrysosporium Pb (25 µM) and Cd (50 µM) independently applied caused ROS formation and time-dependent changes in the activity of CAT, POX, lignin peroxidase (LiP), and manganese peroxidase (MnP).…”

“…The intracellular enzymes such as CAT and POX showed a similar trend in the activity, however, HM-mediated induction of CAT and POX was lower than that in LiP and MnP (Zhang et al 2015 ). Response of A. alternata to Cu sulphate salt provoked a visible growth inhibition that correlated with significant increase in the total protein pool and CAT activity (Shoaib et al 2015 ). The antioxidant response of pathogenic fungi under HMs stress involves also SOD, which has been shown to be required for full virulence in the models C. albicans , C. neoformans and Aspergillus fumigatus (Warris and Ballou 2019 ).…”