DOWN-REGULATION OF NTR GENES BY RNAi IN THE cad2 MU-TANT IMPAIRS PLANT DEVELOPMENT OF Arabidopsis thaliana

The NADPH-Thioredoxin System (NTS) and NADPH Glutathione System (NGS) are the two major thiol reduction systems that play a key role in the maintenance of cellular redox homeostasis and several plant developmental processes. Crosstalk between these two thiol reduction systems has been studied by associating TRX reductase (ntra ntrb) and glutathione biosynthesis (cad2) mutations. Triple ntra ntrb cad2 mutant revealed a new phenotype related to flower meristem development. Unfortunately, this mutant is unfertile and therefore it cannot be maintained at a homozygous stage. In this study, we used the RNAi technique to obtain close similar phenotype to this mutant, but that are fertile. RNAi strategy is performed by down-regulating the expression of both NTR genes by introducing RNAi construct harbouring two head-to-tail copies of the NTRA gene in the genetic background of the cad2 mutant. The transformed plants obtained exhibit attenuated phenotypes compared to the ntra ntrb cad2 mutant. Remarkably, no plants exhibit the characteristic pin-like phenotype of the ntra ntrb cad2 mutant was obtained. However, some plants looks fertile but show a decrease of the apical dominance. Others are more affected and show unfertile flowers. Our data show that the RNAi strategy is an efficient strategy to generate fertile plants with down-regulated NTS and NGS reduction systems and to investigate the crosstalk between these two thiol systems.