The immune receptor BNT1 is involved in Myzus persicae infestation of Arabidopsis

Mendoza

Congreso; Reunión anual Edición LVIII. SAIB. Mendoza Nov 2022; 2022

Sociedas Argentina de Inv en Bioquimica y Biologia Molecular

Nucleotide-binding leucine-rich repeat receptors (NLRs) are key sensors of the plant immune system, conferring resistance to diseases caused by diverse pathogens. NLRs have been found to act in several compartments inside the cell. However, NLRs have never been described as functioning from plastids, which are essential organelles for a successful defense against pathogens. Interestingly, we have recently found that one splice variant of the Arabidopsis NLR receptor BNT1 display a functional plastid targeting signal. The BNT1.1 variant localizes to the cytoplasm while BNT1.2 is targeted to the plastid envelope. Thus, the differential activation of the BNT1 isoforms could play distinctive roles in plant defense responses against pathogens. Here, we analyzed the level of the BNT1.1 and BNT1.2 transcripts in different tissues and under multiple biotic interactions. We found that BNT1.2 show the highest expression in most of the leaf tissues and conditions tested. However, in response to the aphid Myzus persicae infestation the BNT1.1 variant was specifically induced in vascular tissue. Moreover, aphid-responsive marker genes expression was altered in BNT1 loss-of-function plants. Taking this into account, we tested the performance of M. persicae in WT and bnt1 mutant plants. Remarkably, the Electrical Penetrations Graphs Assays showed that, among the 120 feeding activities tested, the aphid spent more time ingesting sap from the phloem of bnt1 mutant. This strongly suggests that the aphid?s performance is higher in the bnt1 null-mutant than in WT plants. However, the Choice Assays revealed that aphids preferred WT over bnt1 plants. Together, our results might indicate a specific requirement for the cytoplasm or chloroplast located BNT1 at different stages of the aphid infestation. Future experiments complementing bnt1 mutant with each of the variants will shed light into this attractive possibility.