1a.Objectives (from AD-416):
To identify and characterize novel endogenous sources of resistance to ear rot and aflatoxin accumulation in corn.
1b.Approach (from AD-416):
The focus of this research will be on a subset of the proteins that have been
identified in proteomic screening conducted at the USDA/ARS/SRRC lab, as putatively involved in aflatoxin accumulation and/or ear rot resistance. Identified proteins will be further characterized and the corresponding genes will be isolated and cloned. Proteins will be expressed in a suitable in vitro system and their possible physiological functions will be investigated. Knowledge of A. flavus functional genomics techniques will be used to identify/test proteins for target-specific interruption of aflatoxin biosynthesis. The information obtained through the above studies will be used to explore the potential of the identified genes to serve as markers in marker-assisted breeding programs.
A maize protein interactome has been completed. Such an interactome is used to predict protein-protein interactions in maize and to identify maize proteins involved in resistance to ear rots and to infection by Aspergillus flavus. A manuscript describing the interactome is ready to send to a refereed journal to be considered for publication. A maize gene expression network (a maize transcriptome i.e. a set of all RNA, ribonucleic acid, molecules produced in one population of cells) has also been constructed. This network was built using a series of publically available maize gene expression data in response to biotic (caused by living or once living organisms) and abiotic (caused by non-living such as sunlight, wind) stresses. The maize transcriptome provides a static snapshot of maize genes with similar patterns of expression. This may indicate common regulation, or the involvement of these genes in the same processes. A field experiment was conducted in the Agronomic Research Center at Southern Illinois University. A time-course study of the interaction between maize and Aspergillus (A.) flavus was conducted using four different maize lines: two susceptible to A. flavus, and two resistant to the fungus. Next-generation sequencing is being used to capture gene expression profiles in maize and A. flavus during a narrow window of the early interaction between the two organisms. The field experiment as well and a green house experiment are being repeated this year.