Analysis by virus induced gene silencing of the expression of two proline biosynthetic pathway genes in Nicotiana benthamiana under stress conditions

► We used p4GD-PL as the TMV expression vector for construction of target cDNA inserts. ► We silenced two proline synthetic genes, P5CS and OAT, separately or concomitantly in tobacco. ► P5CS plays a major role in proline accumulation under drought, PEG or ABA treatments. ► OAT plays a minor role in drought or PEG treatment but not in ABA treatment. ► OAT appears to have a close relationship with polyamine levels in PEG and ABA treatments.