Formate dehydrogenase contributes to the early Arabidopsis thaliana responses against Xanthomonas campestris pv campestris infection

Formate dehydrogenase (FDH) catalyzes the conversion of formate (HCOO-) into carbon dioxide (CO2), coupled with the reduction of NAD(+) to NADH. FDH involvement in the response against abiotic stress is well established whereas FDH role against pathogen attack is less known. Therefore, the in silico correlation analysis of the FDH transcript with a biotic stress dataset was performed, which highlighted correlation with genes involved in the response against pathogen attack. Next, a reduction in the expression of an FDH reporter construct in the hydathodes of Arabidopsis thaliana leaves infected with Xanthomonas campestris pv campestris (Xcc) was observed. We also observed an increased proliferation of Xcc in the hydathodes of an atfdh1-5 mutant during the early stages of infection, which further supports FDH involvement in an early defense response activated in the hydathodes upon Xcc infection, possibly through modulation of formate levels.