EFFICACY IN VITRO E IN PLANTA OF THE STRAIN BB20 BIOFORMULATIONS AGAINST DIFFERENT BACTERIAL PATHOGENS
Research Project
Bacterial plant pathogens are one the most important factors that cause serious losses to several crops every year. Plant diseases caused by phytopathogenic bacteria are usually controlled in the frame of integrated programmes, including the application of copper compounds (e.g. copper oxychloride, Bordeaux mixture, etc.) and antibiotics (where allowed by law); however, the routine use of such molecules has various undesirable side effects such as developement pesticide-resistance, poisoning of herbivores (e.g. bees, mammalians, etc.), damages to biodiversity and accumulation in the soil (Nakajima et al., 2002; Goto et al., 2004; Cameron and Sarojini, 2013).
A biological control of plant diseases represents a desirable alternative approach that would limit the use of harmful pesticides. In plant pathology, the term biocontrol indicates the use of microbial antagonists to prevent or treat the onset and the development of the infectious process. Different mode of actions of biocontrol-active microorganisms in controlling plant diseases include hyper parasitism, antibiosis, cross protection, competition for penetration sites and nutrients, and induced resistance (Pusey, 2002; Sundin et al., 2009; Fousia et al., 2015).
From the data available up to date (results of in planta efficacy obtained by BT Biotechnologies by using 24h-grown cultures of BB20), it appears that the wild strain BB20 of Pseudomonas fluorescens (Pf), originally isolated from healthy apple buds cv. Oregon Spur in the district of Ferrara, can be considered as a possible biological control agent (BCA) for use against various plant bacterial diseases.
The present project proposal relates to the use of the novel bacterial strain BB20 of Pseudomonas fluorescens bv. 1 (deposited under the Budapest treaty at DSMZ on Jan 13 2012, with deposit number DSM 25556; Application No./Patent No. 12706932.6 - 1401) as BCA of diseases caused by phytopathogens such as bacteria, and methods for their prevention and management. In particular, the efficacy of several BB20 formulation types will be evaluated by means of in vitro tests against the bacterial pathogens Erwinia amylovora (Ea), Xanthomonas arboricola pv. pruni, Xanthomonas vesicatoria (Xv) and Pseudomonas syringae pv. tomato (Pst), etiological agents of fire blight of Pomaceae plants, spot/canker of stone fruit, spot and speck of tomato, respectively. In vivo tests will be also carried out on different plant organs (i.e. pear flowers and fruitlets etc.); moreover, in planta assays on tomato plants will be also carried out under greenhouse conditions.
All the experiments will be carried out in the laboratory and in the glasshouse of the Department of Agricultural Sciences (DipSA, Plant Pathology area), University of Bologna.
Litterature Cited
Cameron A., and Sarojini V. 2013. Pseudomonas syringae pv. actinidiae: chemical control, resistance mechanisms and possible alternatives. Plant Pathology, 63(1): 1-11.
Fousia S., Paplomatas E.J. and Tjamos S.E. 2016. Bacillus subtilis QST 713 confers protection to tomato plants against Pseudomonas syringae pv. tomato and induces plant defence-related genes . Journal of Phytopathology, 164: 264-270
Goto M., Hikota T., Nakajima M., Takikawa Y., Tsuyumu S., 2004. Occurence and proprieties of copper resistance in plant pathogenic bacteria. Annals of the Phytopathological Society of Japan, 60: 147.
Nakajima M., Goto M., and Hibi T. 2002. Similarity between copper resistance genes from Pseudomonas syringae pv. actinidiae and P. syringae pv. tomato. Journal of General Plant Pathology, 68: 68-74.
Pusey P. L. 2002. Biological control agents for fire blight of apple compared under conditions limiting natural dispersal. Plant Disease, 86: 639-644.
Sundin G. W., Werner N. A., Yoder K. S. and Aldwinckle H. S. 2009. Field evaluation of biological control of fire blight in the eastern United States. Plant Disease, 93: 386-394.
ACTIVITY PLAN
Activity 1: In vitro and in vivo tests with prototype model formulation
- In vitro and in vivo assays against Ea, Xap, Xv or Pst using different BB20 formulations
Activity 2: In vivo and in planta tests with prototype model formulation
- Assessment of the efficacy and stability of the best BB20 formulation by in vivo and in planta tests.
Activity 3: In vitro and in planta tests with prototype model formulation grown in pilot-fermentor
- Assessment of the efficacy and stability of the best BB20 formulation grown in pilot-fermentor by in vitro and in planta tests.
Activity 4: In vitro and in planta tests with prototype model formulation from industrially fermented biomass
- Assessment of the efficacy and stability of the best BB20 formulation resulting from industrially fermented biomass by in planta tests.