IPT9, a cis-zeatin cytokinin biosynthesis gene, promotes root growth
Cytokinin and auxin are plant hormones that coordinate many aspects of plant development. Their interactions in plant underground growth are well established, occurring at the levels of metabolism, signaling, and transport. Unlike many plant hormone classes, cytokinins are represented by more than o...
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Published in | Frontiers in plant science Vol. 13; p. 932008 |
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Main Authors | , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Frontiers Media S.A
14.10.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Cytokinin and auxin are plant hormones that coordinate many aspects of plant development. Their interactions in plant underground growth are well established, occurring at the levels of metabolism, signaling, and transport. Unlike many plant hormone classes, cytokinins are represented by more than one active molecule. Multiple mutant lines, blocking specific parts of cytokinin biosynthetic pathways, have enabled research in plants with deficiencies in specific cytokinin-types. While most of these mutants have confirmed the impeding effect of cytokinin on root growth, the
ipt29
double mutant instead surprisingly exhibits reduced primary root length compared to the wild type. This mutant is impaired in
cis
-zeatin (
c
Z) production, a cytokinin-type that had been considered inactive in the past. Here we have further investigated the intriguing
ipt29
root phenotype, opposite to known cytokinin functions, and the (bio)activity of
c
Z. Our data suggest that despite the
ipt29
short-root phenotype,
c
Z application has a negative impact on primary root growth and can activate a cytokinin response in the stele. Grafting experiments revealed that the root phenotype of
ipt29
depends mainly on local signaling which does not relate directly to cytokinin levels. Notably,
ipt29
displayed increased auxin levels in the root tissue. Moreover, analyses of the differential contributions of
ipt2
and
ipt9
to the
ipt29
short-root phenotype demonstrated that, despite its deficiency on
c
Z levels,
ipt2
does not show any root phenotype or auxin homeostasis variation, while
ipt9
mutants were indistinguishable from
ipt29
. We conclude that IPT9 functions may go beyond
c
Z biosynthesis, directly or indirectly, implicating effects on auxin homeostasis and therefore influencing plant growth. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Ondřej Novák orcid.org/0000-0003-3452-0154 ORCID: Ioanna Antoniadi orcid.org/0000-0001-9053-2788 Present address: Eduardo Mateo-Bonmatí, John Innes Centre, Norwich, United Kingdom Karel Doležal orcid.org/0000-0003-4938-0350 These authors have contributed equally to this work and share first authorship Edited by: Phanchita Vejchasarn, Rice Department of Thailand, Thailand This article was submitted to Plant Development and EvoDevo, a section of the journal Frontiers in Plant Science Michal Karády orcid.org/0000-0002-5603-706X Eduardo Mateo-Bonmatí orcid.org/0000-0002-2364-5173 Colin Turnbull orcid.org/0000-0001-6635-1418 These authors have contributed equally to this work and share second authorship Karin Ljung orcid.org/0000-0003-2901-189X Federica Brunoni orcid.org/0000-0003-1497-9419 Reviewed by: Laila Moubayidin, John Innes Centre, United Kingdom; Jasmina Kurepa, University of Kentucky, United States Markéta Pernisová orcid.org/0000-0002-5803-2879 Aleš Pěnčík orcid.org/0000-0002-1314-2249 Anita Ament orcid.org/0000-0001-5563-7330 |
ISSN: | 1664-462X 1664-462X |
DOI: | 10.3389/fpls.2022.932008 |