Relations between the HI and optical properties of the dwarf galaxies detected in ATLAS^3D HI survey (blue markers) and in ALFALFA (light blue markers) as compared to dwarfs (crosses) from Huang et al. (2012) (red), Bradford et al. (2015) (gray), and Begum et al. (2008a) (gray). We highlight MATLAS dEs with circles and dIs with triangles. Left: gas fraction (top) and log M_HI (bottom) as a function of log M_*. The relations for galaxies with log(M_*/M_⊙) < 8.6 and > 8.6 from Bradford et al. (2015) are represented with dashed lines, while the dotted lines identify the differences of −1 dex from these relations. Right: relations between log M_HI/L_B as a function of M_B (bottom) and the gas fraction as a function of (g − r)₀ (top). The dashed line shows the upper envelope for the HI mass-to-light ratio at a given luminosity from Warren et al. (2007).