Caratterizzazione dell'aggressivita e della sensibilita ai fungicidi di popolazioni di Mycosphaerella graminicola (anamorfo Zymoseptoria tritici) su frumento

Mycosphaerella graminicola anamorph. Zymoseptoria tritici is the casual agent of Septoria Tritici Blotch (STB). The pathogen is widespread in Europe, but in Italy only recently is causing heavy losses of yield. Against STB genetic resistance is an important approach, but disease control mostly rely to fungicide applications. The main aim of the study was test the fungicide sensitivity (QoI, DMI e SDHI) of Italian Z. tritici istrains. This aim led to set up of protocol in droplets digital PCR (ddPCR) to investigate the frequency of G143A substitution causing a reduction of strobilurins’ efficacy. Another aim was test the sensitivity of Italian wheat variety to Z. tritici investigating the specificity of pathogen strains to bread and durum wheat. From the sensitivity test to Qoi, DMI and SDHI and from the analysis of cytb, cyp51 e Sdhb-c-d genes this study showed a reduction of sensitivity of STB strains to QoI and DMI. However all the three family of fungicide can be used in field management of the pathogen but is important follow the anti-resistance strategy proposed by Fungicide Resistance Action Committee. The use of ddPCR made it possible to obtain a sensitive and accurate measurement of the frequencies of G143A substitution. Similar protocols could be developed to investigate other mutations involved in fungicide resistance in Z. tritici as well as in other plant pathogens. The sensitivity of wheat variety to STB was evaluated inoculating the plants with strains collected from bead and durum wheat. The results showed the emergence of specialization of isolates tested to bread and durum wheat but another test could confirm the supposition. The information make from this study could improve the management of Z. tritici in field.