Nomuraea rileyi INHIBITS GROWTH AND BIOFILM FORMATION OF Xanthomonas citri subsp citri

LUJAN ENRIQUE; MARCINKEVICIUS K; D'ALMEIDA, R.E.; FOGLIATA GABRIELA; ARENA MARIO EDUARDO

Tafí del Valle

Congreso; XXXIII ANNUAL SCIENTIFIC MEETING; 2017

Nomuraea rileyi ARSEF 4094, an entomopathogenic fungus (EF) isolated from Spodoptera frugiperda, produces secondarymetabolites (SM) that interfere with the development of infectious insects and bacteria from the insect body. It is known thatthe addition of insects to the fungal growth medium stimulates the production of SM. SM are known to affect bacterial growthin their planktonic and biofilm (BF) states. Therefore, the aim of this study was to evaluate the inhibitory capacity of N. rileyiin the presence of S. frugiperda on Xanthomonas citri subsp. citri (Xcc) growth and BF formation. This bacterium causescitrus canker, the main crop in Tucumán.EF was cultured in SMY medium with S. frugiperda and incubated at 28 °C for 15 days, at 180 rpm. Fungal and insectcontrols with the same treatment were made. Ethyl acetate extracts from biomass and supernatant from each condition wereobtained. Xcc growth inhibition was determined by the microdilution method at 48 h and the inhibition of BF formation wasquantified by a colorimetric method. The extract from fungal-insect biomass was the most efficient in inhibiting BF formation(38%), affecting Xcc growth in only 15%, while the extract from fungal biomass inhibited the growth of the bacteria in 32%and only 9% the formation of BF. According to this, the presence of insects could stimulate the production of SM, whichinterferes with the synthesis of BF. The results showed the potential use of extracts from N. rileyi as a natural strategy that isenvironmentally acceptable for crop protection against diseases caused by pathogenic microorganisms