Required for phyA-controlled responses to continuous far-red light (FRc) conditions, including the inhibition of hypocotyl elongation and the regulation of XTH15/XTR7 expression. Expressed at low level in seedlings, roots, leaves, stems, flowers, and siliques. Induced during germination. Accumulates slightly in seedlings upon de-etiolation; triggered slowly after irradiation with far-red light (FRc). Reduced inhibition of hypocotyl elongation in continuous far-red light (FRc), associated with a strongly attenuated disappearance of XTH15/XTR7 transcripts. Belongs to the metallo-dependent hydrolases superfamily.