Comparison of the Virulence of Space Mutants of Aspergillus oryzae XJ-1 against Adult Locusta migratoria

Biological control methods provide a sustainable approach for reducing agricultural losses caused by locust plagues. Space mutagenesis can generate high numbers of mutations using satellites and spacecrafts, including beneficial and stable mutants. Aspergillus oryzae XJ-1 was recently reported to show high virulence against locusts. We subjected this fungal pathogen to space mutagenesis to obtain more effective strains. Pathogen conidia powder was mutated in the China Space Station for 6 months. We obtained five mutants of A. oryzae XJ-1, TQ201, TQ238, TQ302, TQ549, and TQ555, and all mutants were identified as A. oryzae by molecular techniques. TQ549 showed the highest virulence against adult L. migratoria (LT50: 4.97 +/- 0.21 days); the LT50 of A. oryzae XJ-1 was 5.67 +/- 0.06 days. Both TQ549 and A. oryzae XJ-1 grew most rapidly at 33 degrees C on potato dextrose agar (PDA) plates. There was no significant difference in the growth rate of TQ549 and A. oryzae XJ-1 at 24 degrees C. The colony morphological characteristics of the five mutants on PDA plates differed from that of A. oryzae XJ-1. The space mutant TQ549, which showed high virulence against adult locusts, could be used as a biological control agent for the control of locust infestations.