Fungal colonization improved growth and modulated the expression of myrosinases in black cabbage

The role of beneficial microorganisms, such as mycorrhizas, in improving the resistance to environmental stress of colonized plants is well-known. Plants of Brassicaceae family are of large economic importance, especially for the synthesis of anticarcinogenic compounds such as glucosinolates and their derivatives isothiocyanates. The endophyte fungus Piriformospora indica is able to colonize them and improves their growth and response to environmental stress. However, no information are available on the impact of colonization on glucosinolate metabolism. In this work, colonization of black cabbage (Brassica oleraceacv. Acephala sabellica) is reported as well as the effects on plant growth and on the expression of myrosinase encoding genes, the isothyocianate producing enzymes. Results indicate that P. indica successfully colonized black cabbage as validated by the expression of the marker gene Ptef1. Colonized plants showed increase of biomass weights and shoot length respect to the uncolonized plants and a decrease of myrosinase gene expression. This last finding indicates that P. indica might affect the resistance against biotic stress of black cabbage.