Effect of previous mycorrhizal crop on AMF and bacterial wilt incidence of Tomato

International audienceBacterial wilt, a soilborne disease caused by Ralstonia solanacearum, one of the world's most important phytopathogenic bacteria, is responsible for high economic losses in horticultural crops, especially in tropical and sub-tropical areas. In Martinique (French West Indies), since 1999, a highly virulent population has been identified on solanaceous and cucurbitaceae crops (Wicker, 2007). Agronomic French research team (INRA and CIRAD) study different agroecological strategies to maintain health and productivity of tomato in the fields. However, tomato benefits from mycorrhization when challenged by root pathogens (Gianinazzi, 2010). Effect of previous mycorrhizal crop was assessed by sampling soils from neighbouring agricultural plots one cultivated with tomato, the other one with chive (Allium fistulosum) and compared to a sterilized control soil. Tomato, cv Heatmaster, was cultivated on these soils under greenhouse conditions. Tomatoes grown on Allium fistulosum previous crop showed significant higher rates of mycorrhization. Moreover, no disease incidence was observed on tomatoes grown after Allium fistulosum. On the contrary, the pourcentage of disease incidence reached 80 % on tomatoes grown after tomatoes. This experiment highlights the potential impact of AMF on tomato bacterial wilt bioprotection