Control potency of Trans-cinnamic acid and antifungal metabolites of Xenorhabdus szentirmaii against Alternaria brassicicola

The, antifungal activities of trans-cinamic acid (TCA) and cell-free supernatant (CFS) of X. szentirmaii were evaluated against Alternaria brassicicola that cause Black spot disease. The results showed that TCA was more suppressive than CFS of X. szentirmaii in the control of A. brassicicola. In petri assays, the highest suppressive effect on spore germination was in TCA treatments compared to CFS of X. szentirmaii. Moreover, no germ tube elongation was observed in any of tested concentrations (0.25%, 0.50%, 1%, 2%) of TCA. The highest level of mycelial growth inhibitions (100% and 92%) were exhibited by TCA (2%) and TCA (1%), respectively. The curative and protective activity of TCA on disease severity of A. brassicicola were also evaluated on broccoli plants. In the curative activity assays, disease severities were 71.00%, 56.33% and 54.03% for control, TCA (1%) and TCA (2%), respectively. Whereas in the protective activity, TCA (2%) suppressed the disease severity significantly greater than TCA (1%). The disease severity of A. brassicicola after TCA application on broccoli plants was 25.21% and 17.37% for TCA (1%) and TCA (2%) respectively. Similar data were obtained in the efficacy of TCA on A. brassicicola. In the curative activity assays, TCA (1%) and TCA (2%) exhibited the efficacy with rates of 20.57% and 23.02%, respectively. However, TCA (2%) showed significantly higher efficacy than TCA (1%) in the protective activity. The current study provides that TCA has a great potential to suppress A. brassicicola and can be a good alternative to synthetic fungicides. Bu çalışmada trans-cinnamik (TCA) ve Xeorhabdus szentirmaii bakteri süpernatatının (CFS) kara leke hastalığı etmeni Alternaria brassicicola’ya karşı antifungal etkinliği test edilmiştir. Sonuçlara bakıldığında TCA, X szentirmaii’nin süpernatantına göre A. brassicicola üzerinde daha etkili olmuştur. Petri deneylerinde A. brassicicola’nın sporlarının çimlenmesini en fazla baskılayan deney grubunun TCA olduğu görülmüştür. Ayrıca TCA’nın tüm konsantrasyonlarının (%0.25, %0.50, %1, %2) hiçbirisinde çim borusu gelişimini gözlenmemiştir. A. brassicicola’nın misel gelişimini en fazla inhibe eden (%100 ve %92 oranlarında) TCA konsantrasyonları ise sırasıyla yüzde 2 ve yüzde 1’dir. A. brassicicola’nın hastalık şiddeti üzerine TCA’nın koruyucu ve tedavi edici etkisi brokoli fideleri kullanılarak test edilmiştir. Tedavi edici denemelerde, hastalık şiddeti kotrolde %71 iken TCA (1%) ve TCA (2%) uygulanan