DELLA proteins play a central role in gibberellin (GA) signaling. GA triggers DELLA degradation (降解) via the ubiquitin-proteasome pathway (泛素-蛋白酶体通路), thereby promoting plant growth. An increase in cytosolic (细胞质的) Ca2+ ([Ca2+]cyt) was previously observed after several hours GA application. Recent studies also suggest the existence of a DELLA-independent GA response. However, the effect of DELLA on the GA-induced increase in [Ca2+]cyt remains unknown. This study re-examined the effects of GAs on [Ca2+]cyt using the Ca2+ sensor protein aequorin (发光蛋白质). [Ca2+]cyt increased within a few minutes of GA treatment, even in transgenic plants expressing a mutated degradation-resistant version of RGA and in della pentuple mutant plants. In addition, it was also revealed that Ca2+ is not involved in DELLA degradation. These results suggest that the GA-induced increase in [Ca2+]cyt occurs via a DELLA-independent pathway, providing important information on the GA signaling network.

First Published data: October 24, 2017.