Growth kinetic and nitrogen source optimization for liquid culture fermentation of Metarhizium robertsii blastospores and bioefficacy against the corn leafhopper Dalbulus maidis

Autor(es)

Iwanicki, Natasha St'Anna ^[1] ; Mascarin, Gabriel Moura ^[2] ; Moreno, Sara Giro ^[1] ; Eilenberg, Jorgen ^[3] ; Delalibera Junior, Italo ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Entomol & Acarol, Escola Super Agr Luiz de Queiroz, ESALQ USP, Av Padua Dias 11, CP 9, Piracicaba 13418900, SP - Brazil

^[2] Brazilian Agr Res Corp, Lab Environm Microbiol, Embrapa Environm, Rodovia SP 340, Km 127-5, Jaguariuna 13820000 - Brazil

^[3] Univ Copenhagen, Dept Plant & Environm Sci, Thorvaldsensvej 40, Frederiksberg 1871 - Denmark

• Tipo de documento: Artigo Científico
• Fonte: WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY; v. 36, n. 5 APR 28 2020.
• Citações Web of Science: 0

Resumo

The cosmopolitan entomopathogenic and root endophytic fungus Metarhizium robertsii has a versatile lifestyle and during liquid fermentation undergoes a dimorphic transformation from hyphae to conidia or microsclerotia, or from hyphae to blastospores. In all cases, these processes are mediated by environmental and nutritional cues. Blastospores could be used in spray applications to control arthropod pests above ground and may serve as an attractive alternative to the traditional solid-grown aerial conidial spores of Metarhizium spp. found in commercial products. Nitrogen is a vital nutrient in cell metabolism and growth; however, it is the expensive component in liquid cultures of entomopathogenic fungi. Our goals in this study were to optimize nitrogen sources and titers for maximum production of M. robertsii blastospores cultured in shake flasks at highly aerated conditions and to further determine their virulence against the corn leafhopper Dalbulus maidis, an important vector of serious pathogens in maize crops worldwide. Our fermentation studies revealed that the low-cost corn steep liquor (CSL) was the most suitable nitrogen source to improve blastospore growth in M. robertsii. The growth kinetic assays determined the optimal titer of 80 g L-1 and a yield up to 4.7 x 10(8) cells mL(-1) within 5 days of cultivation (3 days preculture and 2 days culture), at a total cost of US\$0.30 L-1. Moreover, the blastospore growth kinetic was strongly dependent on glucose and nitrogen consumptions accompanied by a slight drop in the culture pH. Insect bioassays evidenced a high virulence of these blastospores, either as dried or fresh cells, to D. maidis adults fed on maize plants. Our findings provide insights into the nutritional requirements for optimal and cost-efficient production of M. robertsii blastospores and elucidate the potential of blastospores as an ecofriendly tool against the corn leafhopper. (AU)

• Processo FAPESP: 16/20610-6 - AVANÇOS NA PRODUÇÃO E FORMULAÇÃO DE BLASTOSPOROS DE Metarhizium E TRANSCRIPTOMA DA FASE DE CRESCIMENTO LEVIDURIFORME
• Beneficiário: Natasha Sant Anna Iwanicki
• Modalidade de apoio: Bolsas no Brasil - Doutorado