RESEARCH ARTICLE Effect of compost tea containing phosphogypsum on potato plant growth and protection against Fusarium solani infection Mariem Samet 1 & Mariam Charfeddine 1 & Lotfi Kamoun 2 & Oumèma Nouri-Ellouze 1 & Radhia Gargouri-Bouzid 1 Received: 12 October 2017 /Accepted: 4 April 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Three composts made of industrial wastes were prepared by mixing olive oil mill waste water (OMW), olive pomace, coffee grounds, and phosphogypsum (0, 10, and 30%). Potato plants (Solanum tuberosum) cultivated in a greenhouse were used to screen compost tea suppressive ability. All compost tea treatments inhibited Fusarium solani growth and improved plant growth and response to F. solani infection. The antagonistic effects of the different treatments were associated with a marked increase of the antioxidant enzymes and PR (pathogenesis related) protein expression and a decrease of disease severity. These results also showed that plant growth and disease suppression were improved by application of phosphogypsum-supplemented compost teas (A10 and A30). This enhancement can be attributed to the influence of phosphogypsum on nutrient elements and microbial diversity in the resulting compost teas. Keywords Wastes . Phosphogypsum . Compost tea . Potato . Fusarium solani Introduction Potato (Solanum tuberosum) is one of the world’ s most impor- tant food crops playing an important role in food security and nutrition worldwide. However, it is subjected to several biotic problems caused by many phytopathogens such as the soil borne fungi (Pernezny et al. 2014) leading to important eco- nomic losses (Bruehl 1987). The fungal mycelial structure can enter into the roots of plants and spread to neighbor ones. Most of the pathogenic fungus species display wide host range, and the production of resistant spores and conidia allow them to survive under different environmental conditions. Therefore, the control of these plants pathogens is very difficult (Raaijmakers et al. 2009). Fusarium solani is one of the most important fungus in- fecting potato plants causing huge economical losses. It can colonize potato roots or tubers leading to severe reduction of yield and poor plant development (Li et al. 2009). This hemibiotrophic fungus (Ma et al. 2013) colonizes plant tissues and synthesizes effectors proteins such as toxins and enzymes that kill host’ s cells (Mendgen and Hahn 2002; Horbach et al. 2011). Chemical control methods have been widely used, but the abusive use of fungicides to cure or prevent plant diseases presents major risks for plants, soil, environment, and humans. Biological treatment methods appear as the most promising technique to replace conventional chemical control systems, as they are cost-effective and environmentally safe (Ongena and Jacques 2008). In this context, the use of com- posts shows great promise for improving soil quality, crop production, plant growth, and also to suppress many diseases caused by soil-borne plant pathogens (Chaney et al. 1980; Lumsden et al. 1983; Hoitink and Fahy 1986; Chen et al. 1987; Mays and Giordano 1989; Atiyeh et al. 2001). Composting is a fermentation process that converts raw organic waste materials into biologically stable humic by product called Bcompost^ which makes excellent soil amend- ment (Adani et al. 1995). Both the microbial activity and the physicochemical properties of composts play crucial roles in disease suppression (Vallad and Goodman 2004; Spatafora Responsible editor: Philippe Garrigues * Mariem Samet mariemsamet@rocketmail.com 1 Laboratoire d’Amélioration des Plantes et Valorisation des Agro-ressources, Ecole Nationale d’Ingénieurs de Sfax, Route Soukra Km 4, B.P 1173, 3038 Sfax, Tunisia 2 Groupe Chimique Tunisien, Direction de la Recherche Scientifique, Sfax, Tunisia Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-1960-z