Top left: SFR–M _⋆ diagram integrated over CALIFA SFR and stellar maps, color-coded by the total molecular gas mass, M _mol. The solid black line is the SFMS fit by Cano-Díaz et al. (2016). Blue, green, and red shaded areas define main-sequence, green valley, and red cloud galaxies, respectively, as defined by the bands (see Section 4.1 for more details). Top right: SFR–M _mol relation color-coded by stellar mass. The dashed black lines, from top to bottom, correspond to molecular gas depletion times τ _dep = 0.1, 1.0, and 10 Gyr, respectively. Blue, green, and red circles are the centroids of SFR and M _mol values for galaxies with 5σ CO detections (filled circles) of the groups as defined by the bands in the top left panel. The blue and green squares correspond to the centroid of SFR and M _mol values for main-sequence and green valley CARMA EDGE–detected galaxies. Bottom: distributions for the molecular-to-stellar mass fraction (﹩{R}_{\star }^{\mathrm{mol}}={M}_{\mathrm{mol}}/{M}_{\star };﹩ left) and the molecular gas depletion time (τ _mol = M _mol/SFR; right) for the three categories (excluding CO upper limits) as defined in top left panel. Vertical and horizontal lines correspond to the average values and the standard deviations of the distributions, respectively. The plots suggest that while the transition from main-sequence to green valley galaxies is mostly driven by gas removal/depletion, the movement from the latter to the red cloud may be determined by a reduction in the SFE of the molecular gas (SFE﹩{}_{\mathrm{mol}}={\tau }_{\mathrm{dep}}^{-1}﹩).