Journal
JOURNAL OF FUNGI
Volume 7, Issue 4, Pages -Publisher
MDPI
DOI: 10.3390/jof7040284
Keywords
peanut; Aspergillus flavus; fungicide; azoxystrobin; seed infection
Categories
Funding
- Georgia Seed Development Commission
Ask authors/readers for more resources
Aspergillus flavus infects peanuts and produces carcinogenic aflatoxin. In 2020, peanut seeds in Georgia had low germination due to contamination. Aspergillus isolates showed resistance to azoxystrobin, necessitating the development of new seed treatment fungicides.
Aspergillus flavus infects peanuts and produces a mycotoxin called aflatoxin, a potent human carcinogen. In infected peanuts, it can also affect peanut seed quality by causing seed rot and reducing seed viability, resulting in low germination. In 2020, peanut seeds in Georgia had lower than expected germination and a high frequency of A. flavus contamination. A total of 76 Aspergillus isolates were collected from seven seed lots and their identity and in vitro reaction to QoI (quinone outside inhibitor) fungicide (azoxystrobin) were studied. The isolates were confirmed as A. flavus by morphological characteristics and a PCR (polymerase chain reaction)-based method using species-specific primers. In vitro, these isolates were tested for sensitivity to azoxystrobin. The mean EC50 values ranged from 0.12 to 297.22 mu g/mL, suggesting that some isolates were resistant or tolerate to this fungicide. The sequences of cytochrome b gene from these isolates were compared and a single nucleotide mutation (36.8% isolates) was found as Cyt B G143A, which was associated with the total resistance to the QoIs. Another single mutation (15.8% isolates) was also observed as Cyt B F129L, which had been documented for QoI resistance. Therefore, a new major single mutation was detected in the A. flavus natural population in this study, and it might explain the cause of the bad seed quality in 2020. The high frequency of this new single nucleotide mutation exists in the natural population of A. flavus and results in the ineffectiveness of using azoxystrobin seed treatment. New seed treatment fungicides are needed.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available