The polyamine uptake transporters PUT2/LAT4 and PUT5/LAT5 contribute to Arabidopsis defense response against .

UNLABELLED

Under biotic stress, plant polyamine metabolism undergoes significant changes, including increased biosynthesis and catabolism, which lead to hydrogen peroxide production. However, the roles of polyamine mobilization and transport across membranes remain elusive. encodes five Polyamine Uptake Transporters (PUT1-PUT5). In this study, we investigated the role of polyamine transport in during its interaction with the necrotrophic fungus (). Fungal inoculation induced the expression of all / genes at different times throughout disease progression. To assess their contribution to defense, we challenged five homozygous mutants ( to ) with . Notably, and exhibited increased susceptibility to , which was further exacerbated in the double mutant. Spermidine supplementation had a reduced effect on enhancing resistance in mutants, while it increased resistance in the overexpression lines, suggesting that spermidine transport contributes to plant defense. Consistently, spermidine treatment elevated endogenous spermidine levels in WT but had minimal effect on , , or the double mutant. In contrast, spermine supplementation raised endogenous spermine levels in all genotypes, even under infection. Under mock conditions, catalase and ascorbate peroxidase activities were elevated in mutants, while polyamine oxidase activity remained unchanged. These antioxidant enzymes and polyamine oxidase activity were induced upon infection in WT but not in mutants. Thus, disruptions in polyamine transport may affect their catabolism and the plant antioxidant response. This research emphasizes the importance of PUT-mediated polyamine transport in the plant's defense response to .

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-025-01630-1.