GENETIC DISSECTION OF PINE1 CONTROLLED STEM ELONGATION AND NEW INSIGHTS INTO LONG DAY FLOWERING IN ORYZA SATIVA
type: CreativeWork
description: Rice flowering is promoted by exposure to short days (SD) and occurs through the coordination of two developmental processes: the shoot apical meristem (SAM) produces an inflorescence while, along the stem, internodes elongate to allow heading. Recently, PREMATURE INTERNODE ELONGATION1 (PINE1), a C2H2 zinc f inger transcription factor, was described as the responsible for stem elongation during flowering and under submergence in deepwater rice. PINE1 is highly expressed when the stem is compact and it is rapidly downregulated as the plant needs to elongate internodes, which occurs during flowering induction in normal paddy rice as well as under submergence in deepwater rice. pine1 mutants shows constitutive internode elongation since germination. In this thesis, morphological studies with EdU staining assay were performed, revealing that the premature internode elongation is due to intercalary meristem (IM) development followed by cell elongation. Premature internode elongation was associated with pine1 mutants of wheat and maize as well, thus showing a conserved role of PINE1 among these species. Rice pine1 mutants are highly responsive to gibberellins (GA) as their internodes rapidly elongate proportionally to the exogenous GA concentration, contrary to WT stems whose growth is unaffected. To understand how PINE1 may be involved in the GA signalling pathway, we have generated single and double knockout mutants with CRISPR-Cas9 of pine1 and four well-characterized genes belonging to GA biosynthesis, perception and signalling pathways: GIBBERELLIN INSENSITIVE DWARF1 (GID1), GIBBERELLIN INSENSITIVE DWARF2 (GID2), SEMI-DWARF (SD1) AND SLENDER RICE1 (SLR1). Two novel gain-of-function dominant mutations in SLR1 were also identified. The novel dominant slender mutants (named slrD) lacks two aminoacids close to the DELLA motif and might be crucial for its degradation, causing SLR1 overaccumulation and dwarf phenotype. Double mutants pine1-gid1, pine1-gid2 and pine1-slrD, …
abstract: Rice flowering is promoted by exposure to short days (SD) and occurs through the coordination of two developmental processes: the shoot apical meristem (SAM) produces an inflorescence while, along the stem, internodes elongate to allow heading. Recently, PREMATURE INTERNODE ELONGATION1 (PINE1), a C2H2 zinc f inger transcription factor, was described as the responsible for stem elongation during flowering and under submergence in deepwater rice. PINE1 is highly expressed when the stem is compact and it is rapidly downregulated as the plant needs to elongate internodes, which occurs during flowering induction in normal paddy rice as well as under submergence in deepwater rice. pine1 mutants shows constitutive internode elongation since germination. In this thesis, morphological studies with EdU staining assay were performed, revealing that the premature internode elongation is due to intercalary meristem (IM) development followed by cell elongation. Premature internode elongation was associated with pine1 mutants of wheat and maize as well, thus showing a conserved role of PINE1 among these species. Rice pine1 mutants are highly responsive to gibberellins (GA) as their internodes rapidly elongate proportionally to the exogenous GA concentration, contrary to WT stems whose growth is unaffected. To understand how PINE1 may be involved in the GA signalling pathway, we have generated single and double knockout mutants with CRISPR-Cas9 of pine1 and four well-characterized genes belonging to GA biosynthesis, perception and signalling pathways: GIBBERELLIN INSENSITIVE DWARF1 (GID1), GIBBERELLIN INSENSITIVE DWARF2 (GID2), SEMI-DWARF (SD1) AND SLENDER RICE1 (SLR1). Two novel gain-of-function dominant mutations in SLR1 were also identified. The novel dominant slender mutants (named slrD) lacks two aminoacids close to the DELLA motif and might be crucial for its degradation, causing SLR1 overaccumulation and dwarf phenotype. Double mutants pine1-gid1, pine1-gid2 and pine1-slrD, …
author: BERTAGNON, GRETA
language: eng
keywords: Stem elongation, GA signalling, Long-day flowering regulation, Settore BIOS-01/A - Botanica generale
date published: 2026-03-27
date modified: 2026-07-27T20:19:08Z
provider: Università degli Studi di Milano
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Università degli Studi di Milano

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property ID: Handle
value: https://hdl.handle.net/2434/1227104