Ethylene regulates the timing of leaf senescence in <i>Arabidopsis</i>

TLDR

Ethylene is a plant hormone that regulates various developmental processes, including specialized programmed senescence such as fruit ripening and flower petal senescence. The study aimed to investigate how ethylene influences leaf senescence by employing the ethylene‑insensitive Arabidopsis mutant etr1‑1. Researchers compared rosette leaf senescence between etr1‑1 and wild‑type plants to assess ethylene’s role. Compared with wild‑type, etr1‑1 leaves lived ~30 % longer, showed delayed senescence‑associated gene induction, maintained higher photosynthesis‑associated gene expression, exhibited lower photosynthetic activity, and ultimately underwent functional senescence despite the extended lifespan.

Abstract

Summary The plant hormone ethylene influences many aspects of plant growth and development, including some specialized forms of programmed senescence such as fruit ripening and flower petal senescence. To study the relationship between ethylene and leaf senescence, etr1‐1 , an ethylene‐insensitive mutant in Arabidopsis , was used. Comparative analysis of rosette leaf senescence between etr1‐1 and wild‐type plants revealed that etr1‐1 leaves live approximately 30% longer than the wild‐type leaves. Delayed leaf senescence in etr1‐1 coincided with delayed induction of senescence‐associated genes (SAGs) and higher expression levels of photosynthesis‐associated genes (PAGs). In wild‐type plants, exogenous ethylene was able to further accelerate induction of SAGs and decrease expression of PAGs. The extended period of leaf longevity in etr1‐1 was associated with low levels of photosynthetic activity. Therefore, the leaves in etr1‐1 functionally senesced even though the apparent life span of the leaf was prolonged.