Auxin induces specific Ca2+ pattern and the expression of CMI1.

(A) Confocal images of root expressing the YC3.6-free Ca2+ sensor prior to auxin treatment (mock) and after treatment with 10 μM NAA (“NAA”). The same is imaged after 100 and 160 sec of NAA treatment. (B) Images of a root with schematic representations of auxin and Ca2+ signal distribution at the root tip and the SCN. (C) Expression of pCMI1::CMI1-GUS in and transcription-transactivation driven pCMI1>>mRFP-CMI1 primary root meristem. (D) Microarray expression data showing the induction of CMI1 by auxin is reduced in axr1 auxin response mutant background. (E) Expression level and pattern of pCMI1-driven CMI1-GUS in cmi1 mutant background without (mock) and 2 hours following treatment with 10 μM NAA (“NAA”). Scale bars, (A) 20 μm and (C and E) 50 μm. Underlying data for this figure can be found in S1 Data. axr1, auxin-resistant 1; CMI1, Ca2+-dependent modulator of ICR1; GUS, β-glucuronidase; IAA, indole-3-acetic acid; NAA, 1-Naphthaleneacetic acid; SCN, stem cell niche; YC3.6, Yellow Cameleon 3.6.