BABA effects on the behaviour of potato cultivars infected by Phytophthora infestans and Fusarium solani
Since most plants possess resistance mechanisms which can be induced upon pre-treatment with a variety of chemical compounds, the use of β-aminobutyric acid (BABA) as a defence inducer without reported toxic effect on the environment was studied. The aim of this work was to analyse the effectiveness of BABA to induce resistance againstPhytophthora infestansandFusarium solaniin potato cultivars differing in their level of resistance to late blight. The behaviour of some components of biochemical mechanisms by which BABA increases resistance againstP. infestans, as well as the effect of BABA on the activity of a potential pathogenic factor ofF. solani, were studied. Plants with four applications of BABA throughout the crop cycle produced tubers more resistant toP. infestansandF. solanithan non-treated plants. In addition, tuber slices from treated plants, inoculated withP. infestans,showed an increase in phenol and phytoalexin content. The aspartyl proteaseStAP1 accumulation was also higher in tubers obtained from treated plants and inoculated withP. infestans. This result was observed only in the more resistant potato cv. Pampeana, early after infection. In the potato–F. solaniinteraction, infected tubers coming from BABA-treated plants showed minor fungal proteolytic activity than infected, non-treated ones. For potato cvs Pampeana and Bintje, the BABA treatment improved the yield of harvested tubers. The number of tubers per plant and total weight of harvested tubers was greater for those obtained from treated plants with two early or four applications of BABA. The results show that the BABA treatment increases the resistance of potatoes but the degree of increase depends on the original level of resistance present in each cultivar.