I am plant breeding and biotechnology student. My thesis research goal was to identify genomic regions associated with Maize Lethal Necrosis (MLN). My work was able to identify candidate genes that are potentially associated with resistance to this disease. This project was done at CIMMYT. Previously, I did my undergraduate, Bsc. Biochemistry, at Kenyatta University.
My career objectives are to be part of a system that is involved in identification of novel genes important for improvement of crop production while utilizing both new and novel genomic tools.
Currently, I am enrolled as a Ph.D. student at Iowa State University (ISU), where I am working under MLN gene editing program, sponsored by CIMMYT
Maize lethal necrosis (MLN) is a viral disease caused by dual infection of two viruses Maize chlorotic mottle virus and Sugarcane mosaic virus resulting in devastating effects on maize production. Maize is susceptible to MLN from the seedling stage to maturity, and the management and control of the disease is costly to smallholder farmers. Development of host plant resistance will be an effective method of MLN control. Little is known about the causal genes and molecular mechanisms underlying the resistance. To identify genetic loci associated with MLN resistance, two independent sets of mapping populations were developed. From a set five F2 bi-parental mapping populations, the most resistant and most susceptible individuals were genotyped and marker-trait association analysis was performed through Genome Wide Association Study. GWAS revealed a major effect QTL on chromosome 6 (qMLN_06.157) that was significantly associated (P < 1 X 10-8) with MLN resistance. While using seven independent segregating populations, the favourable allele from KS23 at qMLN_06.157 was validated and fine-mapped to a 0.4cM interval. Candidate gene analysis using maize reference genome, B73, revealed a eukaryotic transcription initiation factor (elF) in this interval. elFs have previously been shown to be involved in plant viral resistance. Eight SNPs within/adjacent to the target window have been identified which co-segregate with MLN. This study provides important insights into the genetic architecture underlying resistance to MLN, establishes a tenable target for gene editing in GRMZM2G073535, and presents a useful set of polymorphic SNPs to be used in breeding for MLN resistance.
Prof. Kahiu Ngugi
Dr. Evans Nyaboga
Dr. Michael S. Olsen