Botrytis cinerea is a necrotrophic plant pathogen, attacking more than 200 crop species worldwide. It causes gray mold on different plant organs including blossoms, fruits, leaves, stems etc. and is considered to belong within the Top 10 list of the most important plant pathogenic fungi. The most devastated losses occur in vegetables such as tomato, lettuce, and beans and in small fruits such as grape, strawberry, blackberry etc. Moreover, it can grow effectively over long periods at cold conditions in fruits such as kiwifruit, apples and pears, causing postharvest rots. In Sweden, Botrytis cinerea is the most serious fungal disease in forest nurseries. It forms sclerotia, which are structures able to survive for long periods under harsh environmental conditions
The management of this disease is based on chemical pesticides. However, this practice has been arisen major concerns, since most of these chemical compounds are highly toxic to humans and animals. Moreover, development of resistance by B. cinerea to most of these site-specific fungicides is also a serious drawback of chemical control. Biological control could be a solution in B. cinerea management. It is an environmental friendly practice, and furthermore there is no risk of resistance development. Different biological control agents have been used against this pathogen, including fungi such as Trichoderma spp. and Aureobasidium pullulalans or bacterial strains such Bacillus spp. However, the biological control faces many challenges and it is highly influenced by environmental and other factors.
Bacillus amyloliquefaciens MBI 600 is a novel strain that has been shown to be effective against many soilborne plant pathogens, such as Fusarium oxysporum Schlecht. f.sp. radicis-lycopersici (Forl), Fusarium oxysporum f.sp. radicis-cucumerinum (Forc), Pythium aphanidermatum and P. ultimum. Preliminary data suggest that in dual cultures of the plant pathogen and the BCA, an inhibition of the mycelial growth is observed. The aim of this project is to investigate the molecular basis of this inhibition, using different techniques, such as RNA-seq analysis, RT-qPCR and gene deletion. The results from this study would give us new insights into B. cinerea physiology, a better understanding of the bacterial-fungal interactions on the phyllosphere and opportunities for expanding the activity spectrum of this biological control agent (BCA) against foliar/fruit pathogens such as Botrytis cinerea.