CLE2regulates light-dependent carbohydrate metabolism in Arabidopsis shoots

Key message This study focused on the role of CLE1-CLE7 peptides as environmental mediators and indicated that root-induced CLE2 functions systemically in light-dependent carbohydrate metabolism in shoots. Plants sense environmental stimuli and convert them into cellular signals, which are transmitted to distinct cells and tissues to induce adequate responses. Plant hormones and small secretory peptides often function as environmental stress mediators. In this study, we investigated whether CLAVATA3/EMBRYO SURROUNDING REGION-RELATED proteins, CLE1-CLE7, which share closely related CLE domains, mediate environmental stimuli inArabidopsis thaliana. Expression analysis ofCLE1-CLE7revealed that these genes respond to different environmental stimuli, such as nitrogen deprivation, nitrogen replenishment, cold, salt, dark, and sugar starvation, in a sophisticated manner. To further investigate the function ofCLE2, we generated transgenic Arabidopsis lines expressing the beta-glucuronidasegene under the control of theCLE2promoter or expressing theCLE2gene under the control of an estradiol-inducible promoter. We also generatedcle2-1andcle2-2mutants using the CRISPR/Cas9 technology.In these transgenic lines, dark induced the expression ofCLE2in the root vasculature. Additionally, induction ofCLE2in roots induced the expression of various genes not only in roots but also in shoots, and genes related to light-dependent carbohydrate metabolism were particularly induced in shoots. In addition,cle2mutant plants showed chlorosis when subjected to a shade treatment. These results suggest that root-induced CLE2 functions systemically in light-dependent carbohydrate metabolism in shoots.