Auxins, the hidden player in chloroplast development

Auxin is the 'growth hormone' and modulation of its concentration correlates with changes in photosynthesis and respiration, influencing the cellular energy budget for biosynthesis and proliferation. However, the relative importance of mechanisms by which auxin directly influences photosynthesis and respiration, or vice versa, are unclear. Here we bring together recent evidence linking auxin with photosynthesis, plastid biogenesis, mitochondrial metabolism and retrograde signalling and through it we propose three hypotheses to test to unify current findings. These require delving into the control of auxin conjugation to primary metabolic intermediates, translational control under auxin regulation and post-translational influences of auxin on primary metabolic processes.

show abstract

“…A correlative link between auxin and chloroplast development has been reported (reviewed in Salazar‐Iribe & De‐la‐Peña, 2020) (Fig. 1).…”

Section: How Does Auxin Influence Chloroplast Development and Physiol...mentioning

confidence: 78%

How is auxin linked with cellular energy pathways to promote growth?

Tivendale

Millar

2022

New Phytologist

View full text Add to dashboard Cite

show abstract

“…Taken together, current evidence indicates that auxin might modulate the chloroplast compartment of cells by controlling cell division and expansion, but also that it has the capacity to act more directly on Cp and PhANGs. However, the majority of studies have concentrated on auxin and fruit chloroplast development (Salazar‐Iribe & De‐la‐Peña, 2020) highlighting the need for further research on leaf tissue and specific cell types in this organ.…”

Section: Hormones: Coordinators Of Cell and Chloroplast Development T...mentioning

confidence: 99%

Chloroplast development in green plant tissues: the interplay between light, hormone, and transcriptional regulation

et al. 2021

View full text Add to dashboard Cite

Chloroplasts are best known for their role in photosynthesis, but they also allow nitrogen and sulphur assimilation, amino acid, fatty acid, nucleotide and hormone synthesis. How chloroplasts develop is therefore relevant to these diverse and fundamental biological processes, but also to attempts at their rational redesign. Light is strictly required for chloroplast formation in all angiosperms and directly regulates the expression of hundreds of chloroplast-related genes. Light also modulates the levels of several hormones including brassinosteriods, cytokinins, auxins and gibberellins, which themselves control chloroplast development particularly during early stages of plant development. Transcription factors such as GOLDENLIKE1&2 (GLK1&2), GATA NITRATE-INDUCIBLE CARBON METABOLISM-INVOLVED (GNC) and CYTOKININ-RESPONSIVE GATA FACTOR 1 (CGA1) act downstream of both light and phytohormone signalling to regulate chloroplast development. Thus, in green tissues transcription factors, light signalling and hormone signalling form a complex network regulating the transcription of chloroplast-and photosynthesis-related genes to control the development and number of chloroplasts per cell. We use this conceptual framework to identify points of regulation that could be harnessed to modulate chloroplast abundance and increase photosynthetic efficiency of crops, and to highlight future avenues to overcome gaps in current knowledge.

show abstract

“…In addition to hypocotyl elongation and leaf development, SAV3 also mediates chlorophyll accumulation and nitrogen assimilation. The importance of auxin in the induction of chlorophyll has been reported in both algae and plants ( Salazar-Iribe and De-la-Peña, 2020 ). Recently, it was reported that in Camellia sinensis seedlings exposed to shade and with a high accumulation of chlorophyll, a positive correlation between auxin and genes involved in chlorophyll biosynthesis such as HEMA1 (glutamyl-tRNA reductase 1), PORA (protochlorophyllide oxidoreductase A), CLH1 (chlorophyllase 1), and CAO (chlorophyllide a oxygenase) was observed ( Liu et al, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Shade Avoidance 3 Mediates Crosstalk Between Shade and Nitrogen in Arabidopsis Leaf Development

Yang

Zhang

et al. 2022

Front. Plant Sci.

View full text Add to dashboard Cite

After nitrogen treatments, plant leaves become narrower and thicker, and the chlorophyll content increases. However, the molecular mechanisms behind these regulations remain unknown. Here, we found that the changes in leaf width and thickness were largely compromised in the shade avoidance 3 (sav3) mutant. The SAV3 gene encodes an amino-transferase in the auxin biosynthesis pathway. Thus, the crosstalk between shade and nitrogen in Arabidopsis leaf development was investigated. Both hypocotyl elongation and leaf expansion promoted by the shade treatment were reduced by the high-N treatment; high-N-induced leaf narrowing and thickening were reduced by the shade treatment; and all of these developmental changes were largely compromised in the sav3 mutant. Shade treatment promoted SAV3 expression, while high-N treatment repressed SAV3 expression, which then increased or decreased auxin accumulation in cotyledons/leaves, respectively. SAV3 also regulates chlorophyll accumulation and nitrogen assimilation and thus may function as a master switch responsive to multiple environmental stimuli.

show abstract

Auxins, the hidden player in chloroplast development

Cited by 31 publications

References 129 publications

How is auxin linked with cellular energy pathways to promote growth?

How is auxin linked with cellular energy pathways to promote growth?

Chloroplast development in green plant tissues: the interplay between light, hormone, and transcriptional regulation

Shade Avoidance 3 Mediates Crosstalk Between Shade and Nitrogen in Arabidopsis Leaf Development

Contact Info

Product

Resources

About