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

ABSTRACT: 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 AtP4H3 T-DNA knock out mutant line showed higher sensitivity to anoxic treatment possibly due to lower induction of the fermentation pathway genes, ADH and PDC1, and of sucrose synthases, SUS1 and SUS4. 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 p4h3 line. These results indicate active involvement of proline hydroxylation, a post-translational modification, to low oxygen response in Arabidopsis.

SUBMITTER: Konkina A

PROVIDER: S-EPMC8006943 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Sre1, the fission yeast sterol regulatory element-binding protein, is an ER membrane-bound transcription factor that controls adaptation to low oxygen growth. Under low oxygen, Sre1 is proteolytically cleaved and the N-terminal transcription factor domain (Sre1N) is released from the membrane and enters the nucleus to activate hypoxic gene expression. Ofd1, a prolyl 4-hydroxylase-like 2-oxoglutarate dioxygenase, controls the oxygen-dependent stability of Sre1N. In the presence of oxygen, Ofd1 accelerates the degradation of Sre1N, but under low oxygen Ofd1 is inhibited and Sre1N accumulates. To identify the regulators of Sre1N, we performed a plasmid-based screen for genes that increased Sre1N transcriptional activity. Here, we identify Nro1 (SPCC4B3.07) as a positive regulator of Sre1N stability and a direct inhibitor of Ofd1. In the absence of oxygen, Nro1 binds to the Ofd1 C-terminal degradation domain and inhibits Sre1N degradation. In the presence of oxygen, Nro1 binding to Ofd1 is disrupted, leading to rapid degradation of Sre1N. We conclude that the Ofd1 dioxygenase domain functions as an oxygen sensor that regulates binding of Nro1 to Ofd1 to control oxygen-dependent Sre1N stability.

| S-EPMC2634736 | biostudies-literature

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