Universität zu Köln

Krone, Raissa (2025). Phosphate starvation responses in dicot and monocot C4 species. PhD thesis, Universität zu Köln.

PDF RaissaKrone_Dissertation_Veroeffentlichung.pdf Download (88MB)

Abstract

C4 photosynthesis increases photosynthetic efficiency by lowering the need for photorespiration by spatially separating CO2 assimilation among two cell types. The C4 cycle has evolved several times independently in various plant families including monocots and dicots. Closely related C3 and C4 species from the monocot genus Panicum and the dicot genus Flaveria were utilized here. Since C4 plants have been shown to make several adaptations to their nitrogen and sulfur metabolism, this study aims to describe their phosphate homeostasis and their responses to phosphate starvation in comparison to C3 plants. Phosphate is an essential plant nutrient involved in many essential processes and a component of key metabolites e.g., ATP, DNA and lipids. This study shows that phosphate is allocated towards the shoots in C4 plants of different genera, likely due to a higher phosphate demand during the C4 cycle. Furthermore, the C3 plant showed induced NPQ and reduced ETR, indicating regulation of light reactions. In contrast, their C4 counterpart displayed an impaired CO2 assimilation rate under phosphate limitation, probably due to substrate limitation. However, this was not observed for the C4 monocot, which might be explained by a more efficient phosphate starvation response achieved through its stronger induction of the miRNA399. While it confirmed that the C4 dicot is more affected by the deprivation, the analysis of metabolic adaptation to phosphate limitation involving carbohydrates, TCA cycle intermediates, amino acids and nucleotides revealed mainly species- or genus-specific effects.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Krone, Raissa raissa.krone@gmx.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-790650
Date:	2025
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Botanical Institute
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language C4 Photosynthesis English Phosphate starvation English Mineral nutrition English
Date of oral exam:	6 October 2025
Referee:	Name Academic Title Kopriva, Stanislav Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/79065