Vitamin B6 contributes to disease resistance against Pseudomonas syringae pv. tomato DC3000 and Botrytis cinerea in Arabidopsis thaliana

Vitamin B6 (VB6) is an important cofactor for numerous enzymatic reactions and plays an important role in abiotic stress tolerance. However, direct molecular evidence supporting a role for VB6 in plant disease resistance remains lacking. In this study, we explored the possible function of VB6 in disease resistance by analyzing disease phenotypes of Arabidopsis mutants with defects in de novo biosynthetic pathway and salvage pathway of VB6 biosynthesis against Pseudomonas syringae pv. tomato (Pst) DC3000 and Botrytis cinerea. Mutations in AtPDX1.2 and AtPDX1.3 genes involved in the de novo pathway, and in AtSOS4 gene involved in the salvage pathway led to increased levels of diseases caused by Pst DC3000 and B. cinerea. The pdx1.2 and pdx1.3 plants had reduced VB6 contents and showed a further reduction in VB6 contents after infection by Pst DC3000 or B. cinerea. Our preliminary results suggest an important role for VB6 in plant disease resistance against different types of pathogens.