Assessing the genetic and molecular basis of resistance to Fusarium Verticillioides in maize

Maize (Zea mays L.) is an extraordinary crop among the most important worldwide for food, feed, biofuels, and industrial applications. With more than one billion tonnes harvested every year, maize is the highest production cereal species. In its global distribution, maize faces significant constraints due to many pathogens affecting the quality and quantity. The disease may have a devastating impact on maize cultivation, depending on many factors, including environmental conditions, susceptibility of maize varieties, and agronomic practices. Fusarium species are amongst the most prominent maize pathogens and are responsible for diseases such as seedling blights, ear rots, stalk rots, and root rots. Genetic resistance is considered the most reliable resource to reduce damages caused by Fusarium verticillioides. This study aims to elucidate the genetic and molecular basis of genetic resistance to F. verticillioides in Zea mays, describing the comprehensive gene expression profiles of eight MAGIC maize parental lines after F. verticillioides infection through two main experiments. This experiment aimed to identify comprehensive gene expression profiles of eight MAGIC maize parental lines after inoculation. The experiment was targeted at measuring disease severity and measuring the response after pathogen inoculation by means of RT-PCR of reported genes. With the first one, the goal is to identify the time-point with the highest response after the pathogen inoculation to collect RNA for high-throughput sequencing. Young seedlings of two MAGIC maize parental lines with extreme responses to disease (H99, resistant and Mo17, susceptible) were artificially inoculated with an F. verticillioides strain using the Rolled Towel Assay (RTA), and Fusarium housekeeping genes were quantified with RT-PCR in a time-courses of 48 hours post-inoculation (hpi), 72 hpi, 96 hpi, 120 hpi, 168 hpi. The 72 hpi ended up to be the most appropriate for transcriptome profile. In the second experiment, transcriptional analysis of the eight MAGIC maize founder inbred lines infected with F. verticillioides was performed to identify differential gene expression in response to the pathogen attack. The findings of this experiment include new candidate genes responsible for the resistance to F. verticillioides. A full understanding of the molecular mechanisms underlying the infection process and the corresponding resistance pathways is important to develop innovative breeding programs incorporating disease resistance to cultivated maize.