Essential protein required during embryogenesis. Required for mitochondrial metabolism. Necessary for normal plasmodesmata (PD) development and aperture regulation. ATP + H2O = ADP + H(+) + phosphate Mostly expressed in leaves and flowers, and, to a lower extent, in roots, seedlings and siliques, especially in meristematic regions. The Q motif is unique to and characteristic of the DEAD box family of RNA helicases and controls ATP binding and hydrolysis. Embryogenesis mostly arrested at globular stage and cotyledon stage. Altered size exclusion limit of PD; abnormally maintained dilated PD at the torpedo stage and increased formation of secondary branched PD. Chlorosis (PubMed:11779812, PubMed:11874921, PubMed:19805190, PubMed:20434343). Altered plastid development (PubMed:22106293). Belongs to the DEAD box helicase family.