Abstract:
Eutypa latais one of the predominant causal agents of grapevine trunk disease (GTD). This fungal pathogen can cause severe disease of grapevines and results in reduced yield or plant death. GTDs exist widely in New Zealand and their influence is getting more significant by year. Aureobasidium pullulans is a fungal endophyte that naturally colonizing grapevines and has been used as a biological control agent in other crops. A. pullulans shows proven efficacy reducing severity of fungal infections against GTD pathogens such as Diplodia seriata. In this study, four A. pullulans strains were purchased and tested in vitro and in planta for their potential of inhibiting growth and movement of E. lata in grapevines. In silico study the abundance of A. pullulans in the total fungal microbiome varied among vineyards. Contemporary-managed vineyards and Pinot Noir have higher A. pullulans abundance than future-managed vineyards and Sauvignon Blanc. A high abundance of A. pullulans reduced biomass of E. lata, but neither of two species has a direct association with GTD symptoms. In vitro and in vivo results suggested A. pullulans has potential to inhibit E. lata but further studies were required. A. pullulans has significantly reduced colony size of E. lata when co-inoculated on Potato Dextrose Agar than E. lata was cultured alone. This effect existed for all four A. pullulans strains. When co-inoculated with E. lata, A. pullulans ICMP 3057 and ICMP 21143 was associated with increased leaf presence compared to grapevine canes inoculated with E. lata alone. However, no statistical evidence supported A. pullulans conferring a reduced stain size on cane samples.
