Biology subjects

Bouain, N.

Publications and source records attributed to Bouain, N..

4 recordsLinked to original sources

bioRxiv2025

Phosphorus Availability Modulates Flowering Time Through Subcellular Reprogramming of bGLU25 and GRP7 in Flowering Plants

The transition from vegetative to reproductive growth is vital for plant fitness and crop yield and is strongly influenced by nutrient availability. While nitrogen deficiency accelerates flowering, phosphorus (P) limitation delays it. However, the molecular basis for how P availability regulates flowering time remains unclear. Here, through genome-wide association mapping in Arabidopsis, we uncover genetic variation in {beta}-GLUCOSIDASE 25 (bGLU25) that modulates flowering under P-limited conditions. In P-sufficient environments, bGLU25 localizes to the endoplasmic reticulum. Under P limitation, however, bGLU25 translocates to the cytosol, a process mediated by P-regulated SERINE CARBOXY PEPTIDASE 50 (SCP50). In the cytosol, bGLU25 binds to JACALIN-LECTIN LIKE1 (AtJAC1), preventing the nuclear translocation of the Flowering Locus C (FLC) regulator GLYCINE-RICH RNA-BINDING PROTEIN 7 (GRP7). This cytosolic sequestration of GRP7 under P-deprivation elevates FLC expression, delaying flowering. Moreover, in the monocot rice, the homologs of bGLU25 also modulate flowering responses to P availability, indicating a conserved role for bGLU25 across flowering plants. Our findings provide a molecular framework for breeding strategies aimed at optimizing flowering time in response to P levels.

plant biology↗

bioRxiv2021

Interdependent Iron and Phosphorus Availability Controls Photosynthesis Through Retrograde Signaling

Iron deficiency hampers photosynthesis and is associated with chlorosis. We recently showed that iron deficiency-induced chlorosis depends on phosphorus availability. How plants integrate these cues to control chlorophyll accumulation is unknown. Here, we show that iron limitation downregulates photosynthesis genes in a phosphorus-dependent manner. Using transcriptomics and genome-wide association analysis, we identify two genes, a chloroplastic ascorbate transporter (PHT4;4) and a nuclear transcription factor (bZIP58), which prevent the downregulation of photosynthesis genes leading to the stay-green phenotype under iron-phosphorus deficiency. Joint limitation of these nutrients induces ascorbate accumulation by activating expression of an ascorbate biosynthesis gene, VTC4, which requires bZIP58. Exogenous ascorbate prevents iron deficiency-induced chlorosis in vtc4 mutants, but not in bzip58 or pht4;4. Our study demonstrates chloroplastic ascorbate transport is essential for preventing the downregulation of photosynthesis genes under iron-phosphorus combined deficiency. These findings uncover a molecular pathway coordinating chloroplast-nucleus communication to adapt photosynthesis to nutrient availability.

plant biology↗

bioRxiv2018

Systems approaches provide new insights into Arabidopsis thaliana root growth under mineral nutrient limitation

The molecular genetic mechanisms by which plants modulate their root growth rate (RGR) in response to nutrient deficiency are largely unknown. Using a panel of Arabidopsis thaliana natural accessions, we provide a comprehensive combinatorial analysis of RGR variation under macro- and micronutrient deficiency, namely phosphorus (P), iron (Fe), and zinc (Zn), which affect root growth in opposite directions. We found that while -P stimulates early RGR of most accessions, -Fe or -Zn reduces it. The combination of either -P-Fe or -P-Zn leads to suppression of the growth inhibition exerted by -Fe or -Zn alone. Surprisingly, Arabidopsis reference accession Columbia (Col-0) is not representative of the species under -P and -Zn. Using a genome wide association study, we identify candidate genes that control RGR under the assayed nutrient deficiency conditions. By using a network biology driven search using these candidate genes, we further identify a functional module enriched in regulation of cell cycle, DNA replication and chromatin modification that possibly underlies the suppression of root growth reduction in -P-Fe conditions. Collectively, our findings provide a framework for understanding the regulation of RGR under nutrient deficiency, and open new routes for the identification of both large effect genes and favorable allelic variations to improve root growth.

plant biology↗

bioRxiv2017

Zinc availability modulates plant growth and immune responses via AZI1

Zinc is an essential micronutrient for all living organisms and is involved in a plethora of processes including growth and development, and immunity. However, it is unknown if there is a common genetic and molecular basis underlying multiple facets of zinc function. Here we used natural variation in Arabidopsis thaliana to study the role of zinc in regulating growth. We identify allelic variation of the systemic immunity gene AZI1 as a key for determining root growth responses to low zinc conditions. We further demonstrate that this gene is important for modulating root growth depending on the zinc and defence status. Finally, we show that the interaction of the immunity signal azelaic acid and zinc level to regulate root growth is conserved in rice. This work demonstrates that there is a common genetic and molecular basis for multiple zinc dependent processes and that nutrient cues can determine the balance of plant growth and immune responses in plants.

plant biology↗