Tesi etd-11102023-111915
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Tipo di tesi
Corso Ordinario Secondo Livello
Autore
CAVALLINI, ELENA
URN
etd-11102023-111915
Titolo
Unveiling the multifaceted roles of PP-InsPs beyond phosphate homeostasis
Struttura
Cl. Sc. Sperimentali - Agraria
Corso di studi
SCIENZE AGRARIE E BIOTECNOLOGIE - SCIENZE AGRARIE E BIOTECNOLOGIE
Commissione
Tutor Prof. PERATA, PIERDOMENICO
Relatore Prof. HOTHORN, MICHAEL
Presidente Prof. SEBASTIANI, LUCA
Membro Prof. TONUTTI, PIETRO
Membro Prof.ssa MENSUALI, ANNA
Membro Dott.ssa PELLEGRINO, ELISA
Relatore Prof. HOTHORN, MICHAEL
Presidente Prof. SEBASTIANI, LUCA
Membro Prof. TONUTTI, PIETRO
Membro Prof.ssa MENSUALI, ANNA
Membro Dott.ssa PELLEGRINO, ELISA
Parole chiave
- Arabidopsis
- genetic screen
- nitrate
- PP-InsPs
- transcription factor
- transporter
Data inizio appello
15/12/2023;
Disponibilità
parziale
Riassunto analitico
Inositol pyrophosphates (PP-InsPs) are eukaryotic nutrient messengers controlling plant phosphate homeostasis and starvation responses. The cellular receptors of PP-InsPs are proteins carrying a SPX domain. PP-InsP binding to SPX receptors enables them to interact with other proteins, such as phosphate starvation response transcription factors (PHRs) in plants. Under Pi-sufficient conditions, PP-InsP levels are high and repressive SPX-PHR complexes cannot bind to PHR target promoters. In Pi starvation conditions, PP-InsP biosynthesis is reduced and as a consequence SPX-PHR complexes dissociate, enabling the transcription factors to bind promoters of genes triggering the phosphate starvation response (PSR).
In Arabidopsis, a mutant compromised in the last step of PP-InsP biosynthesis is seedling lethal, due to a constitutively active PSR leading to Pi hyperaccumulation. Consequently, additional deletion of two PHRs leads to a partial rescue of the severe growth phenotype. This only partial rescue, suggest PP-InsP may have additional signaling functions beyond SPX-PHR.
The aim of my thesis is to identify new components of the plant PP-InsP signaling pathway and/or completely new cellular processes being regulated by PP-InsP signaling molecules. From a suppressor genetic screen performed on a PP-InsP biosynthetic and Pi-insensitive mutant I have isolated several candidate genes.
My first candidate is AtMRP5, a member of ABC transporter subfamily C, involved in the transport of inositol hexakisphosphate (InsP6) in the vacuole. InsP6 being the substrate of PP-InsP biosynthetic enzymes, this transporter may play a role in the control of cytosolic PP-InsP and potentially PP-InsP storage or degradation.
The other candidate is HRS1 (NIGT1.4), a nuclear localized MYB-related member of the GARP family of transcription factors with demonstrated roles in nitrate signaling, another essential plant macronutrient. I now propose to investigate the role of PP-InsPs as general nutrient messengers integrating phosphate and nitrate signaling pathways to regulate the balance of these crucial nutrients in the plant.
In Arabidopsis, a mutant compromised in the last step of PP-InsP biosynthesis is seedling lethal, due to a constitutively active PSR leading to Pi hyperaccumulation. Consequently, additional deletion of two PHRs leads to a partial rescue of the severe growth phenotype. This only partial rescue, suggest PP-InsP may have additional signaling functions beyond SPX-PHR.
The aim of my thesis is to identify new components of the plant PP-InsP signaling pathway and/or completely new cellular processes being regulated by PP-InsP signaling molecules. From a suppressor genetic screen performed on a PP-InsP biosynthetic and Pi-insensitive mutant I have isolated several candidate genes.
My first candidate is AtMRP5, a member of ABC transporter subfamily C, involved in the transport of inositol hexakisphosphate (InsP6) in the vacuole. InsP6 being the substrate of PP-InsP biosynthetic enzymes, this transporter may play a role in the control of cytosolic PP-InsP and potentially PP-InsP storage or degradation.
The other candidate is HRS1 (NIGT1.4), a nuclear localized MYB-related member of the GARP family of transcription factors with demonstrated roles in nitrate signaling, another essential plant macronutrient. I now propose to investigate the role of PP-InsPs as general nutrient messengers integrating phosphate and nitrate signaling pathways to regulate the balance of these crucial nutrients in the plant.
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