Changes in resource partitioning between and within organs support growth adjustment to neighbor proximity in
            <i>Brassicaceae</i>
            seedlings

Wit, Mieke de; George, Gavin M.; Ince, Yetkin Çaka; Dankwa-Egli, Barbara; Hersch, Micha; Zeeman, Samuel C.; Fankhauser, Christian

doi:10.1073/pnas.1806084115

Cited by 44 publications

(51 citation statements)

References 64 publications

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“…For picloram (Sigma-Aldrich, Steinheim, Germany, P5575) treatment, nylon meshes were transferred on day 5 before the temperature shift to half strength MS medium with the indicated picloram concentration (0.1% dimethyl sulphoxide (DMSO) for Mock). Seedlings imaging and measurements were described previously (de Wit et al, 2018). Petiole measurements were performed as described (de Wit et al, 2015).…”

Section: Phenotypic Characterization and Growth Conditionsmentioning

confidence: 99%

PHYTOCHROME INTERACTING FACTOR 7 is important for early responses to elevated temperature in Arabidopsis seedlings

et al. 2019

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Summary In response to elevated ambient temperature Arabidopsis thaliana seedlings display a thermomorphogenic response that includes elongation of hypocotyls and petioles. Phytochrome B and cryptochrome 1 are two photoreceptors also playing a role in thermomorphogenesis. Downstream of both environmental sensors PHYTOCHROME INTERACTING FACTOR 4 (PIF4) is essential to trigger this response at least in part through the production of the growth promoting hormone auxin. Using a genetic approach, we identified PHYTOCHROME INTERACTING FACTOR 7 (PIF7) as a novel player for thermomorphogenesis and compared the phenotypes of pif7 and pif4 mutants. We investigated the role of PIF7 during temperature‐regulated gene expression and the regulation of PIF7 transcript and protein by temperature. Furthermore, pif7 and pif4 loss‐of‐function mutants were similarly unresponsive to increased temperature. This included hypocotyl elongation and induction of genes encoding auxin biosynthetic or signalling proteins. PIF7 bound to the promoters of auxin biosynthesis and signalling genes. In response to temperature elevation PIF7 transcripts decreased while PIF7 protein levels increased rapidly. Our results reveal the importance of PIF7 for thermomorphogenesis and indicate that PIF7 and PIF4 likely depend on each other possibly by forming heterodimers. Elevated temperature rapidly enhances PIF7 protein accumulation, which may contribute to the thermomorphogenic response.

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Section: Phenotypic Characterization and Growth Conditionsmentioning

confidence: 99%

PHYTOCHROME INTERACTING FACTOR 7 is important for early responses to elevated temperature in Arabidopsis seedlings

et al. 2019

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“…This suggests that carbon partitioning to starch vs sugars is altered in phyABD and phyABDE seedlings. A recent study analysing the starch biosynthesis mutants pgm1, pgi1, agd2, and the starch degradation mutant sex1 showed that seedling hypocotyl elongation negatively correlates with starch levels (de Wit et al, 2018). Mutants with the longest hypocotyls had the lowest starch levels, suggesting that sugars that are not partitioned to starch are used to grow.…”

Section: Discussion Phy Mutants Undergo a Developmental Switch In Metmentioning

confidence: 99%

“…Phytochromes are proposed to be involved in promoting root growth by cotyledon-derived sucrose (Kircher and Schopfer 2012). Work in Brassica seedlings illustrates that the proportion of assimilated carbon that is partitioned to the hypocotyl doubles in response to low R:FR conditions (de Wit et al 2018). This low R:FR induced change in carbon allocation is mainly dependent on PIF7, with contributions from PIF4 and / or PIF5.…”

Section: Introductionmentioning

confidence: 99%

“…This low R:FR induced change in carbon allocation is mainly dependent on PIF7, with contributions from PIF4 and / or PIF5. Phloem transport of sucrose by the SUC2 and SWEET11 and SWEET 12 transporters is necessary to fuel hypocotyl elongation in response to low R:FR (de Wit et al 2018). Thus in seedlings phys are not only required for altered molecular signalling but also for reprogramming of carbon resource management.…”

Section: Introductionmentioning

confidence: 99%

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Phytochrome light receptors control metabolic flux, and their action during seedling development sets the trajectory for biomass production

Krahmer

Abbas

Mengin

et al. 2019

Preprint

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The phytochromes (phys) photoreceptors are known to be major regulators of plastic growth responses to vegetation shade. Recent reports have begun to uncover an important role for phys in carbon resource management. Our earlier work showed that phy mutants had a distinct metabolic profile with elevated levels of metabolites including TCA intermediates, amino acids and sugars. Here we show that in seedlings phy regulates the balance between glucose and starch. Multi-allele phy mutants have excess glucose and low starch levels, which is conducive to hypocotyl elongation. 13 C-CO 2 labelling demonstrates that metabolic flux balance in adult plants is markedly altered in phy mutants. Phytochrome reduces synthesis rates of stress metabolites, including raffinose and proline and several typical stress-induced biosynthetic genes related to these metabolites show higher expression in phy mutants. Since growth and metabolism are typically inter-connected, we investigated why phy mutants have severely reduced biomass. Quantification of carbon fixation, biomass accumulation, and 13 C labelling of cell wall polysaccharides established that relative growth rate is impaired in multi allele phy mutants for the first 2.5 weeks after germination but equivalent to the WT thereafter. Mathematical modelling predicts that the altered growth dynamics and final biomass deficit can be explained by the smaller cotyledon size of the multiple phy mutants. This indicates that the established role of phy in promoting seedling establishment has enduring effects that govern adult plant biomass.

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“…We propose that barley is preferentially storing its resources in the youngest actively growing tissue where they are required for growth, and then store the excess in other tissues. Under shade by neighboring plants, Arabidopsis actively reallocates starch to the hypocotyls, likely to provide the C required for elongation (de Wit et al, 2018). Under LL, barley not only allocates starch or sucrose, but also malate to the youngest leaf.…”

Section: Light Intensity Affects the Spatial Distribution Of Metabolitesmentioning

confidence: 99%

Transient Carbon Reserves in Barley: Malate, Sucrose and Starch Are the Main Players, Their Quantitative Involvement Being Light Intensity Dependant

et al. 2020

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Under natural environment plants experience different light intensities which can affect photosynthesis and consequently the availability of carbohydrates for daytime growth and their transient storage to supply night growth. We grew a spring barley cultivar, Propino, under three different light intensities under warm days and nights, and evaluated the spatial and diurnal adjustments occurring in the transient carbon stores. Leaves under high light at the end of the day accumulated mainly sucrose (30%) and malate (35%), with lower content of hexoses (5%), starch (15%) and fructans (15%). Under low light, plants presented reduced photosynthesis, with lower metabolite contents at end of day. The malate represented 51% of the total carbon accumulated at end of the day, at the expense of sucrose (12%), other metabolite contributions remaining similar to high light. The percentage of metabolites consumed at night was similar for all light intensities with around 75% of the sucrose and starch being mobilized whilst malate and fructans were only partially mobilized with 56 and 44%, respectively. Altogether, sucrose and malate were the main contributors of the total carbon used at night by barley plants, sucrose being predominant under high light (35% vs. 27%), but malate being the major metabolite used under low light with 40% of the total carbon consumed. Interestingly, light intensity also influenced the location of the C transient stores, the plants under low light prioritizing the accumulation of the metabolites, mostly malate, in the youngest tissues. Therefore, light influences quantitatively, but also qualitatively and spatially the carbon stores in the spring barley cv. Propino, suggesting a tight regulation of the primary metabolism.

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Changes in resource partitioning between and within organs support growth adjustment to neighbor proximity in Brassicaceae seedlings

Cited by 44 publications

References 64 publications

PHYTOCHROME INTERACTING FACTOR 7 is important for early responses to elevated temperature in Arabidopsis seedlings

PHYTOCHROME INTERACTING FACTOR 7 is important for early responses to elevated temperature in Arabidopsis seedlings

Phytochrome light receptors control metabolic flux, and their action during seedling development sets the trajectory for biomass production

Transient Carbon Reserves in Barley: Malate, Sucrose and Starch Are the Main Players, Their Quantitative Involvement Being Light Intensity Dependant

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