Extended Data Figure 2. Mature-guard-cell-targeted carbonic anhydrase catalytic activity suppresses stomatal development via extracellular signalling in ca1 ca4 mutants.

a, Cartoon showing epidermal cell differentiation in an immature cotyledon. Green indicates differentiated epidermis with stomata (shown in b); red indicates epidermal cells that have entered the stomatal lineage (shown in c). b, c, Confocal images of mature (b) or developing (c) stomata in cotyledons at 5 DAG for lines expressing the human CA-II–YFP construct driven by the mature guard cell preferential promoter pGC1 (ref. 16), illustrating mature guard cell targeting of pGC1::CA-II-YFP. Two representative images of the distal end of the cotyledon epidermis, where stomatal differentiation has already occurred (b). Two representative images (the image on the left is at higher magnification) of the proximal end of the cotyledon, where stomatal differentiation has not yet taken place (c). d, The stomatal index of six independent complementation lines of the ca1 ca4 mutant transformed with either CA1–YFP or CA4–YFP (significance of suppression was determined relative to ca1 ca4). All scale bars, 20 µm. Error bars, mean ± s.e.m.; n = 20. ***, P<0.00005; **, P<0.005; *, P<0.05, using ANOVA and Tukey’s post-hoc test.