The accumulation of PAL and PR-1 gene transcription before exposure to corn ear rot infection is an effective factor in resistance to Fusarium fungus

Fusarium ear rot with Fusarium verticillioides is one of the most important corn diseases around the world. Plants respond to pathogens attack by activating complex defense strategies. Defense response to pathogen infection includes changes in the expression of a large number of plant genes which may be a gene expression increase or decrease. Three lines with different resistance levels to fusarium fungus (C7, B73, MO17) cultivated based on RCBD design. After silking manual pollination was carried out and 15 days after that inoculation with fusarium funus was done by syringe (for seed inoculation) or needle (for silk inoculation). Then, silk and corn grain were sampled at 12, 24, 48, 72 and 96 hours after contamination. Non inoculated ear was used as control. After RNA extraction and cDNA production, synthesis the Real-Time PCR technique, the relative expression pattern of PAL, PR-1 genes were measured and data were analyzed using REST software. All genotypes are able to express PAL and PR-1 genes after infection with Fusarium fungus and their only difference is in the level of gene expression. Major changes in the expression of defense genes in the resistant and susceptible lines occur before infection. Resistant line have a high level of expression of PAL and PR-1 genes before contamination and that may be the primary barrier against a pathogen attack, but susceptible line to resistant line, after infection, the expression of PAL, PR-1 genes begins.