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C2 photosynthesis generates about 3-fold elevated leaf CO2 levels in the C3-C4 intermediate species Flaveria pubescens.

ABSTRACT: Formation of a photorespiration-based CO2-concentrating mechanism in C3-C4 intermediate plants is seen as a prerequisite for the evolution of C4 photosynthesis, but it is not known how efficient this mechanism is. Here, using in vivo Rubisco carboxylation-to-oxygenation ratios as a proxy to assess relative intraplastidial CO2 levels is suggested. Such ratios were determined for the C3-C4 intermediate species Flaveria pubescens compared with the closely related C3 plant F. cronquistii and the C4 plant F. trinervia. To this end, a model was developed to describe the major carbon fluxes and metabolite pools involved in photosynthetic-photorespiratory carbon metabolism and used quantitatively to evaluate the labelling kinetics during short-term (14)CO2 incorporation. Our data suggest that the photorespiratory CO2 pump elevates the intraplastidial CO2 concentration about 3-fold in leaves of the C3-C4 intermediate species F. pubescens relative to the C3 species F. cronquistii.

SUBMITTER: Keerberg O

PROVIDER: S-EPMC4085972 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Photosynthesis of C3, C3-C4, and C4 grasses at glacial CO2.

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| S-EPMC4085965 | biostudies-literature

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Photosynthesis in C3-C4 intermediate Moricandia species

Project description:Analysis of the metabolism in mature leaves of Moricandia species with C3 and C3-C4 intermediate photosynthesis

2016-10-01 | GSE87343 | GEO

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Photosynthesis in C3-C4 intermediate Moricandia species

Project description:Photosynthesis in C3-C4 intermediate Moricandia species

| PRJNA344463 | ENA

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| S-EPMC5853325 | biostudies-literature

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| S-EPMC4103682 | biostudies-literature

Despite phylogenetic effects, C3-C4 lineages bridge the ecological gap to C4 photosynthesis.

Project description:C4 photosynthesis is a physiological innovation involving several anatomical and biochemical components that emerged recurrently in flowering plants. This complex trait evolved via a series of physiological intermediates, broadly termed 'C3-C4', which have been widely studied to understand C4 origins. While this research program has focused on biochemistry, physiology, and anatomy, the ecology of these intermediates remains largely unexplored. Here, we use global occurrence data and local habitat descriptions to characterize the niches of multiple C3-C4 lineages, as well as their close C3 and C4 relatives. While C3-C4 taxa tend to occur in warm climates, their abiotic niches are spread along other dimensions, making it impossible to define a universal C3-C4 niche. Phylogeny-based comparisons suggest that, despite shifts associated with photosynthetic types, the precipitation component of the C3-C4 niche is particularly lineage specific, being highly correlated with that of closely related C3 and C4 taxa. Our large-scale analyses suggest that C3-C4 lineages converged toward warm habitats, which may have facilitated the transition to C4 photosynthesis, effectively bridging the ecological gap between C3 and C4 plants. The intermediates retained some precipitation aspects of their C3 ancestors' habitat, and likely transmitted them to their C4 descendants, contributing to the diversity among C4 lineages seen today.

| S-EPMC5853900 | biostudies-literature

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