Plasmodesmata‐located protein overexpression negatively impacts the manifestation of systemic acquired resistance and the long‐distance movement of Defective in Induced Resistance1 in A rabidopsis

Systemic acquired resistance ( SAR ) is a plant defence response that provides immunity to distant uninfected leaves after an initial localised infection. The lipid transfer protein ( LTP ) D efective in I nduced R esistance1 ( DIR 1) is an essential component of SAR that moves from induced to distant leaves following a SAR ‐inducing local infection. To understand how DIR 1 is transported to distant leaves during SAR , we analysed DIR 1 movement in transgenic A rabidopsis lines with reduced cell‐to‐cell movement caused by the overexpression of P lasmodesmata‐ L ocated P roteins PDLP 1 and PDLP 5. These PDLP ‐overexpressing lines were defective for SAR , and DIR 1 antibody signals were not observed in phloem sap‐enriched petiole exudates collected from distant leaves. Our data support the idea that cell‐to‐cell movement of DIR 1 through plasmodesmata is important during long‐distance SAR signalling in A rabidopsis .