An Arabidopsis Prolyl 4 Hydroxylase Is Involved in the Low Oxygen Response.

Plant responses to flooding, submergence and waterlogging are important for adaptation to climate change environments. Therefore, the characterization of the molecular mechanisms activated under hypoxic and anoxic conditions might lead to low oxygen resilient crops. Although in mammalian systems prolyl 4 hydroxylases (P4Hs) are involved in the oxygen sensing pathway, their role in plants under low oxygen has not been extensively investigated. In this report, an Arabidopsis T-DNA knock out mutant line showed higher sensitivity to anoxic treatment possibly due to lower induction of the fermentation pathway genes, and , and of sucrose synthases, and . This sensitivity to anoxia was accompanied by lower protein levels of AGPs-bound epitopes such as LM14 in the mutant line and induction of extensins-bound epitopes, while the expression levels of the majority of the AGPs genes were stable throughout a low oxygen time course. The lower AGPs content might be related to altered frequency of proline hydroxylation occurrence in the line. These results indicate active involvement of proline hydroxylation, a post-translational modification, to low oxygen response in Arabidopsis.