A proteomics approach to study the role of lipid droplets in plant defense

ABSTRACT: Lipid Droplets (LDs), classically viewed as lipid storage particles, are recently emerging as dynamic organelles associated with stress responses and development; however, their involvement in plant immunity has been little investigated. Here we studied LDs in Arabidopsis thaliana leaves that respond to Pseudomonas syringae pv. tomato DC3000 avrRpm1 by inducing a hypersensitive defense reaction (HR), as well as during senescence. We established a protocol to reproducibly isolate LDs from a limited amount of tissue and performed a proteomic analysis of LDs from Pseudomonas-infected (for 24 h and 72 h) and senescent leaves. The proteomes defined shared ~50% similarity, with an enrichment of proteins associated with the Gene Ontology terms “transport” and “responses to stress”. As validation, we confirmed LD localization of glycerol-3-phosphate-acetyltransferase 8 (GPAT8) and GPAT4, enzymes required for e.g., cutin biosynthesis, by transient expression of GFP fusions in HR-induced leaves of Nicotiana benthamiana. Similarly, we proved the localization to LDs of aldehyde dehydrogenase 3F1 (ALDH3F1), α-dioxygenase1 (α-DOX1) and caleosin3 (CLO3), all involved in the synthesis of fatty acid derivatives. Moreover, we found that PAD3 (phytoalexin deficient 3) was distributed in patches along the ER and plasma membrane, and in LDs near dead cells. The nature of these proteins and of the additional components characterized in the LDs, together with the phenotypic examination of selected mutants, established a functional link between LDs and plant immunity. Our data suggest that these organelles participate in protein trafficking and in lipid changes that affect the interaction of plants with invading pathogens.

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Leaf

SUBMITTER: Alberto Paradela  

LAB HEAD: Carmen Castresana

PROVIDER: PXD011499 | Pride | 2022-02-23

REPOSITORIES: Pride