Promoter activities of genes encoding β-galactosidases from Arabidopsis a1 subfamily

► pAtBGAL1, -3 and -4 showed a similar activity pattern related to cell expansion. ► pAtBGAL2 activity was related to hypocotyl elongation in both light and dark conditions. ► pAtBGAL5 was the only one of the subfamily 1 that was active in the trichomes. ► pAtBGAL12 was mainly detected in meristematic zones of the plant.