The authors used a bottom‑up thermodynamic modelling framework to investigate how plants decode calcium signals, starting from Ca2+ binding to EF‑hand proteins and extending to higher‑order decoding modules. They identified six universal Ca2+-decoding modules that can explain variations in calcium sensitivity among kinases and provide a theoretical basis for interpreting calcium signal amplitude and frequency in plant cells.

The study used Arabidopsis thaliana mutants with low (vtc2, vtc4) and high (vtc2/OE-VTC2) ascorbate levels to examine how ascorbate concentration affects gene expression and cellular homeostasis. Transcriptomic analysis revealed that altered ascorbate levels modulate defense and stress pathways, and that TAA1/TAR2‑mediated auxin biosynthesis is required for coping with elevated ascorbate in a light‑dependent manner.

Using hydathode-focused inoculation, the study mapped a major QTL on Arabidopsis chromosome 5 and identified the CNL-type immune receptor SUT1 as a novel resistance gene that restricts early colonization of Xanthomonas campestris pv. campestris in hydathodes. Functional analyses showed SUT1 acts independently of the known RKS1/ZAR1 complex and provides tissue‑specific resistance, being effective primarily in hydathodes but not in xylem.