Kalanchoë PPC1 Is Essential for Crassulacean Acid Metabolism and the Regulation of Core Circadian Clock and Guard Cell Signaling Genes

Feb 14, 2020The Plant cell

The Kalanchoë PPC1 Protein Is Needed for Nighttime Carbon Fixation and Controls Internal Clock and Pore-Opening Genes

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗OA ↗

Abstract

CAM plants exhibit reduced dark period CO2 fixation when PPC is silenced.

Silencing the PPC gene resulted in diminished dark period CO2 fixation and nocturnal malate accumulation.
Plants with silenced PPC showed altered stomatal conductance during the dark period.
The circadian rhythm of CAM CO2 fixation was disrupted under constant light and temperature conditions.
Increased expression of certain genes in the central circadian oscillator was observed in PPC-silenced plants.
Regulatory patterns of guard cell signaling genes were affected, impacting the typical stomatal movement associated with CAM.

AI simplified

Unlike Cplants, Crassulacean acid metabolism (CAM) plants fix COin the dark using phosphopyruvate carboxylase (PPC; EC 4.1.1.31). PPC combines phosphopyruvate with CO(as HCO), forming oxaloacetate. The oxaloacetate is converted to malate, leading to malic acid accumulation in the vacuole, which peaks at dawn. During the light period, malate decarboxylation concentrates COaround Rubisco for secondary fixation. CAM mutants lacking PPC have not been described. Here, we employed RNA interference to silence the CAM isogeneinLinelackedtranscripts, PPC activity, dark period COfixation, and nocturnal malate accumulation. Light period stomatal closure was also perturbed, and the plants displayed reduced but detectable dark period stomatal conductance and arrhythmia of the CAM COfixation circadian rhythm under constant light and temperature free-running conditions. By contrast, the rhythm of delayed fluorescence was enhanced in plants lackingFurthermore, a subset of gene transcripts within the central circadian oscillator was upregulated and oscillated robustly in this line. The regulation of guard cell genes involved in controlling stomatal movements was also perturbed inThese findings provide direct evidence that the regulatory patterns of key guard cell signaling genes are linked with the characteristic inverse pattern of stomatal opening and closing during CAM. 3 2 2 3 2 2 2enol enol PPC1Kalanchoë laxiflora rPPC1-B PPC1PPC1rPPC1-B -

Full Text

Full text is available at the source.

View full text ↗

Kalanchoë PPC1 Is Essential for Crassulacean Acid Metabolism and the Regulation of Core Circadian Clock and Guard Cell Signaling Genes

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief