Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress and future perspectives

Authors: FOUNTAIN, JAKE - University Of Georgia; KHEAR, PAWAN - University Of Georgia; YANG, LIMING - University Of Georgia; NAYAK, SPURTHI - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; Scully, Brian; LEE, ROBERT - University Of Georgia; CHEN, ZHI-YUAN - Louisiana State University; KEMERAIT, ROBERT - University Of Georgia; VARSHNEY, RAJEEV - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; Guo, Baozhu

Submitted to: The Crop Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2015
Publication Date: 4/11/2015
Citation: Fountain, J.C., Khear, P., Yang, L., Nayak, S., Scully, B.T., Lee, R.D., Chen, Z., Kemerait, R.C., Varshney, R.K., Guo, B. 2015. Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress and future perspectives. The Crop Journal. 3(2015):229-237. doi: org/10.1016/j.cj.2015.02.003.

Interpretive Summary: The colonization of grain and oilseed crops by Aspergillus flavus and A. parasiticus results in the contamination of agricultural products with aflatoxins. Aflatoxins are among the most potent mycotoxins, carcinogenic and teretogenic compounds, produced during infection and growth of fungi A. flavus and A. parasiticus. Despite considerable advances in molecular research, the interactions between A. flavus and its hosts remain undefined and there is need for thorough investigation. In this review we focus on recent findings related to the biochemistry of defense regulation and inter-cellular communication between A. flavus and the host crops. In addition, recent advances in breeding for aflatoxin resistance in maize and peanut and the potential utilization of molecular markers for use in marker assisted selection in breeding programs are highlighted. However, one question that has been raised about the role of aflatoxin in the biology and ecology of Aspergillus fungi as well as its role in pathogenesis including the role of aflatoxin as a source of cellular oxidative stress remains answered.

Technical Abstract: The colonization of maize (Zea mays L.) and peanut (Arachis hypogaea L.) by the fungal pathogen Aspergillus flavus and A. parasiticus results in the contamination with carcinogenic mycotoxins known as aflatoxins leading to economic losses as well as a potential health threat to human. The interaction between these crops and A. flavus has been the subject of extensive research and has been shown to consist of a highly complex series of signaling pathways and mechanisms. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has also been extensively studied and has been shown to be related to oxidative stress responses. With the knowledge of high degree of environmental stress and such abiotic stresses resulting in the accumulation of reactive oxygen species (ROS) within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technology advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptiomic studies in the context of productive breeding populations including bi-parental and association mapping formats. Here, we review the current understanding of the biochemical interaction that exists between A. flavus and its host plants, the current status in breeding for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut, and propose future directions for continuing research efforts. However, one question that has been raised about the role of aflatoxin in the biology and ecology of Aspergillus fungi as well as its role in pathogenesis including the role of aflatoxin as a source of cellular oxidative stress remains answered.