ACCELERATED CELL DEATH 6 is a crucial genetic factor shaping the natural diversity of age- and salicylic acid-induced leaf senescence in Arabidopsis

Abstract

Leaf senescence is a crucial process throughout evolution, vital for plant fitness as it facilitates the gradual shift of energy allocation between photosynthesis and catabolism overtime. This onset is influenced by a complex interplay of genetic and environmental factors, making senescence a key adaptation mechanism for plants in their natural habitats. Our study investigated the genetic mechanism underlying age-induced leaf senescence in Arabidopsis natural populations. Using a phenome high-throughput investigator, we comprehensively analyzed senescence responses across 234 Arabidopsis accessions and identified that environmental factors (e.g., ambient temperature) and physiological factors (e.g., defense responses) are substantially linked to senescence phenotypes. Through genome-wide association mapping, we identified the ACCELERATED CELL DEATH 6 (ACD6) locus as a potential regulator of senescence variation among natural accessions. Knocking out ACD6 in accessions with early and delayed senescence phenotypes resulted in varying degrees of delay in age-induced senescence, highlighting the accession-dependent regulatory role of ACD6 in leaf senescence. Furthermore, our findings suggest ACD6's involvement in senescence regulation via the salicylic acid signaling pathway. In summary, our study sheds light on the genetic regulation of leaf senescence in Arabidopsis natural populations, with the discovery of ACD6 as a potential candidate for genetic modification to enhance plant adaptation and survival. © 2024 Scandinavian Plant Physiology Society.