The study demonstrates that subfamily I ethylene receptors form the core ethylene‑sensing module and act epistatically over subfamily II receptors, uniquely possessing Ca2+‑permeable channel activity that drives ethylene‑induced cytosolic calcium influx. This reveals a mechanistic link whereby subfamily I receptors integrate hormone perception with calcium signaling in plants.

Using a microfluidic valve rootchip, the study simultaneously tracked ROS and calcium dynamics in compressed roots and found three kinetic phases linking mechanosensitive channel activity, NADPH oxidase‑dependent ROS accumulation, and secondary calcium influx. Pharmacological inhibition revealed that a fast calcium response is mediated by plasma‑membrane mechanosensitive channels, while a slower calcium increase is driven by ROS production.

The study used quantitative proteomics and co‑fractionation mass spectrometry to uncover rapid ethylene‑induced changes in protein abundance and complex formation during early seedling development, revealing extensive protein multimerization events that correlate with hypocotyl growth modulation. Small‑scale validation confirmed several identified proteins impact hypocotyl development, highlighting novel components of ethylene‑mediated growth regulation.

Reduced activity of methylthioadenosine (MTA) nucleosidase causes MTA over‑accumulation in reproductive tissues, leading to lowered cysteine, methionine, and S‑adenosylmethionine levels and altered sulfur and energy metabolism. These metabolic disturbances trigger misregulation of cell‑cycle progression, widespread down‑regulation of developmental genes, and genome‑wide changes in DNA methylation patterns, highlighting the extensive role of MTA recycling in plant growth and methyl‑index maintenance.