Activation of Aflatoxin Biosynthesis Alleviates Total ROS in Aspergillus parasiticus

作者：Kenne Gabriel J.; Gummadidala Phani M.; Omebeyinje Mayomi H.; McFadden Sandra; Bromfield Sydney; Banaszek Nora; Velez-Martinez Michelle; Mitra Chandrani; Mikell Isabelle; Chanda Anindya^*; Mondal Ananda M.; Bett Dominic K.; Chatterjee Saurabh; Wee Josephine; Chanda A^*

来源：Toxins, 2018, 10(2): 57.

DOI：10.3390/toxins10020057

• aflatoxin
• aflatoxin biosynthesis
• Aspergillus
• reactive oxygen species
• superoxide dismutase
• This work illustrates how aflatoxin biosynthesis contributes to the management of total ROS in Aspergillus parasiticus
• an established model for studying mycotoxin biosynthesis and secondary metabolism in filamentous fungi
• We show that activation of aflatoxin biosynthesis reduces total ROS production in this fungus
• which at least in part
• is jointly mediated by the aflatoxin pathway regulator
• aflR

An aspect of mycotoxin biosynthesis that remains unclear is its relationship with the cellular management of reactive oxygen species (ROS). Here we conduct a comparative study of the total ROS production in the wild-type strain (SU-1) of the plant pathogen and aflatoxin producer, Aspergillus parasiticus, and its mutant strain, AFS10, in which the aflatoxin biosynthesis pathway is blocked by disruption of its pathway regulator, aflR. We show that SU-1 demonstrates a significantly faster decrease in total ROS than AFS10 between 24 h to 48 h, a time window within which aflatoxin synthesis is activated and reaches peak levels in SU-1. The impact of aflatoxin synthesis in alleviation of ROS correlated well with the transcriptional activation of five superoxide dismutases (SOD), a group of enzymes that protect cells from elevated levels of a class of ROS, the superoxide radicals (O-2(-)). Finally, we show that aflatoxin supplementation to AFS10 growth medium results in a significant reduction of total ROS only in 24 h cultures, without resulting in significant changes in SOD gene expression. Our findings show that the activation of aflatoxin biosynthesis in A. parasiticus alleviates ROS generation, which in turn, can be both aflR dependent and aflatoxin dependent.

• 出版日期2018-2