About event
The seminars are devoted to topics that develop directions of the research groups of the Mendel Center for Plant Genomics and Proteomics. The speakers are primarily prominent foreign and domestic experts. In addition, some seminars are dedicated to the presentation of research results by internal speakers, mainly postdoctoral fellows and PhD candidates. Seminars are thus a platform for sharing knowledge, establishing cooperation and developing communication skills.
More information
Ethylene signaling and autophagy both play pivotal roles in plants, including in senescence and responses to stress. Although several studies have suggested their crosstalk, direct evidence is lacking. We speculated that this might be further clarified in a climacteric fruit ripening context, where ethylene can reach 50-fold its output compared to plant vegetative stages. Ripening is a biochemically complex process involving color, flavor, and texture changes, having significant agronomical, environmental, economic, and health implications.
Silencing the essential autophagy genes, SlATG2, SlATG7, and SlATG4, specifically in mature fruits, accelerated ripening. Notably, autophagy deficiency resulted in early entry into climacteric ethylene production, and 1-MCP, an ethylene antagonist, abrogated the early ripening phenotype, suggesting that autophagy restricts ripening via ethylene repression. A similar outcome was observed beyond ripening in Arabidopsis atg5 and atg7 knockout seedlings, showing increased ethylene emission and sensitivity to its ACC precursor.
To gain mechanistic insight, protein-protein interaction screens conducted by us and others have highlighted the ethylene biosynthesis enzymes ACC-Oxidase (ACO) 2 and ACO4 as ATG8-interacting proteins. We further validated this by employing Co-IP. Concomitantly, the increased level of both enzymes in atg5 and atg7 mutants indeed suggests their turnover depends on autophagy. Both ACO2 and 4 contain a predicted ATG8-Interacting Motif (AIM) that is located in proximity to the structurally deduced ACC-binding site of ACO2, raising the intriguing possibility that ACC-loaded or -unloaded ACO enzymes may have different affinities to ATG8.
Collectively, our research describes a crucial role of autophagy in climacteric fruit ripening and deepens our understanding of the autophagy-ethylene crosstalk in plants.
