Cytokinin biosynthesis promotes cortical cell responses during nodule development

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Cytokinin biosynthesis promotes cortical cell responses during nodule development. / Reid, Dugald Elgin; Nadzieja, Marcin; Novák, Ondrej; Heckmann, Anne Birgitte; Sandal, Niels; Stougaard, Jens.

In: Plant Physiology, Vol. 175, No. 1, 09.2017, p. 361-375.

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Reid, Dugald Elgin ; Nadzieja, Marcin ; Novák, Ondrej ; Heckmann, Anne Birgitte ; Sandal, Niels ; Stougaard, Jens. / Cytokinin biosynthesis promotes cortical cell responses during nodule development. In: Plant Physiology. 2017 ; Vol. 175, No. 1. pp. 361-375.

Bibtex

@article{d65a2130be954779bff2e91ce4f0840e,
title = "Cytokinin biosynthesis promotes cortical cell responses during nodule development",
abstract = "Legume mutants have shown the requirement for receptor-mediated cytokinin signalling in symbiotic nodule organogenesis. While the receptors are central regulators, cytokinin is also accumulated during early phases of symbiotic interaction but the pathways involved have not yet been fully resolved. To identify the source, timing and effect of this accumulation, we followed transcript levels of the cytokinin biosynthetic pathway genes in a sliding developmental zone of Lotus japonicus roots. LjIpt2 and LjLog4 were identified as the major contributors to the first cytokinin burst. The genetic dependence and Nod factor (NF) responsiveness of these genes confirms that cytokinin biosynthesis is a key target of the common symbiosis pathway. Accumulation of LjIpt2 and LjLog4 transcripts occurs independent of the LjLhk1 receptor during nodulation. Together with the rapid repression of both genes by cytokinin, this indicates that LjIpt2 and LjLog4 contribute to, rather than respond to, the initial cytokinin build-up. Analysis of cytokinin response using the synthetic cytokinin sensor, TCSn, showed that this response occurs in cortical cells before spreading to the epidermis in L. japonicus. While mutant analysis identified redundancy in several biosynthesis families, we found that mutation of LjIpt4 limits nodule numbers. Overexpression of LjIpt3 or LjLog4 alone was insufficient to produce robust formation of spontaneous nodules. In contrast, overexpressing a complete cytokinin biosynthesis pathway leads to large, often fused spontaneous nodules. These results show the importance of cytokinin biosynthesis in initiating and balancing the requirement for cortical cell activation without uncontrolled cell proliferation.",
keywords = "Journal Article",
author = "Reid, {Dugald Elgin} and Marcin Nadzieja and Ondrej Nov{\'a}k and Heckmann, {Anne Birgitte} and Niels Sandal and Jens Stougaard",
note = "{copyright, serif} 2017 American Society of Plant Biologists. All rights reserved.",
year = "2017",
month = sep,
doi = "10.1104/pp.17.00832",
language = "English",
volume = "175",
pages = "361--375",
journal = "Plant Physiology",
issn = "0032-0889",
publisher = "American Society of Plant Biologists",
number = "1",

}

RIS

TY - JOUR

T1 - Cytokinin biosynthesis promotes cortical cell responses during nodule development

AU - Reid, Dugald Elgin

AU - Nadzieja, Marcin

AU - Novák, Ondrej

AU - Heckmann, Anne Birgitte

AU - Sandal, Niels

AU - Stougaard, Jens

N1 - {copyright, serif} 2017 American Society of Plant Biologists. All rights reserved.

PY - 2017/9

Y1 - 2017/9

N2 - Legume mutants have shown the requirement for receptor-mediated cytokinin signalling in symbiotic nodule organogenesis. While the receptors are central regulators, cytokinin is also accumulated during early phases of symbiotic interaction but the pathways involved have not yet been fully resolved. To identify the source, timing and effect of this accumulation, we followed transcript levels of the cytokinin biosynthetic pathway genes in a sliding developmental zone of Lotus japonicus roots. LjIpt2 and LjLog4 were identified as the major contributors to the first cytokinin burst. The genetic dependence and Nod factor (NF) responsiveness of these genes confirms that cytokinin biosynthesis is a key target of the common symbiosis pathway. Accumulation of LjIpt2 and LjLog4 transcripts occurs independent of the LjLhk1 receptor during nodulation. Together with the rapid repression of both genes by cytokinin, this indicates that LjIpt2 and LjLog4 contribute to, rather than respond to, the initial cytokinin build-up. Analysis of cytokinin response using the synthetic cytokinin sensor, TCSn, showed that this response occurs in cortical cells before spreading to the epidermis in L. japonicus. While mutant analysis identified redundancy in several biosynthesis families, we found that mutation of LjIpt4 limits nodule numbers. Overexpression of LjIpt3 or LjLog4 alone was insufficient to produce robust formation of spontaneous nodules. In contrast, overexpressing a complete cytokinin biosynthesis pathway leads to large, often fused spontaneous nodules. These results show the importance of cytokinin biosynthesis in initiating and balancing the requirement for cortical cell activation without uncontrolled cell proliferation.

AB - Legume mutants have shown the requirement for receptor-mediated cytokinin signalling in symbiotic nodule organogenesis. While the receptors are central regulators, cytokinin is also accumulated during early phases of symbiotic interaction but the pathways involved have not yet been fully resolved. To identify the source, timing and effect of this accumulation, we followed transcript levels of the cytokinin biosynthetic pathway genes in a sliding developmental zone of Lotus japonicus roots. LjIpt2 and LjLog4 were identified as the major contributors to the first cytokinin burst. The genetic dependence and Nod factor (NF) responsiveness of these genes confirms that cytokinin biosynthesis is a key target of the common symbiosis pathway. Accumulation of LjIpt2 and LjLog4 transcripts occurs independent of the LjLhk1 receptor during nodulation. Together with the rapid repression of both genes by cytokinin, this indicates that LjIpt2 and LjLog4 contribute to, rather than respond to, the initial cytokinin build-up. Analysis of cytokinin response using the synthetic cytokinin sensor, TCSn, showed that this response occurs in cortical cells before spreading to the epidermis in L. japonicus. While mutant analysis identified redundancy in several biosynthesis families, we found that mutation of LjIpt4 limits nodule numbers. Overexpression of LjIpt3 or LjLog4 alone was insufficient to produce robust formation of spontaneous nodules. In contrast, overexpressing a complete cytokinin biosynthesis pathway leads to large, often fused spontaneous nodules. These results show the importance of cytokinin biosynthesis in initiating and balancing the requirement for cortical cell activation without uncontrolled cell proliferation.

KW - Journal Article

U2 - 10.1104/pp.17.00832

DO - 10.1104/pp.17.00832

M3 - Journal article

C2 - 28733389

VL - 175

SP - 361

EP - 375

JO - Plant Physiology

JF - Plant Physiology

SN - 0032-0889

IS - 1

ER -