Characterization of Brazilian Cordyceps fumosorosea isolates: Conidial production, tolerance to ultraviolet-B radiation, and elevated temperature

Author(s)

Rojas, Victor Manuel Arevalo ; Iwanicki, Natasha SantAnna ; D'Alessandro, Celeste Paola ; Fatoretto, Maira Blumer ; Demetrio, Clarice Garcia Borges ; Delalibera Jr, Italo

• Document type: Journal article
• Source: Journal of Invertebrate Pathology; v. 197, p. 9-pg., 2023-01-30.

Abstract

Cordyceps fumosorosea is an entomopathogenic fungus with a global distribution and is used for the biological control of agricultural pests. High conidial productivity and tolerance to abiotic stresses such as elevated tem-perature and ultraviolet radiation (UV-B) are desired characteristics in candidate isolates for commercial products. Our goal in this study was to characterize promising isolates of C. fumosorosea from five Brazilian biomes regarding conidial production, tolerance to UV-B, and elevated temperature (45 degrees). Seventy-two isolates out of 172 were chosen visually, based on growth and sporulation in culture medium, and grown on parboiled rice. Next, fourteen isolates were selected, based on productivity on rice and origin of isolation, for production in polypropylene bags and submitted to UV-B for 2, 4, 6, and 8 h or to 45 degrees C for 30, 60, and 90 min. High variations in conidial production were observed among isolates, and a positive correlation was observed between UV-B and heat tolerance. The isolates ESALQ4556 and ESALQ4778 showed the highest yields of conidial production in polypropylene bags (3.51 x 109 conidia/g dry rice), while ESALQ1296, an isolate recovered from insects, was the most tolerant to UV-B and 45 degrees C. Exposure to radiation for more than 4 h and placed directly at 45 degrees C for more than 30 min significantly reduced conidial germination for all C. fumosorosea isolates. These results contribute to a better understanding of the tolerance to abiotic factors of Brazilian isolates of C. fumosorosea. (AU)

• FAPESP's process: 11/51556-3 - IMBICONT: Improved biological control for IPM in fruits and berries
• Grantee: Italo Delalibera Júnior
• Support Opportunities: Regular Research Grants