KNOTTED1-LIKE HOMEOBOX 3: a new regulator of symbiotic nodule development

Azarakhsh, Mahboobeh; Kirienko, Anna; Zhukov, Vladimir A.; Lebedeva, Maria A.; Долгих, Е. А.; Лутова, Л. А.

doi:10.1093/jxb/erv414

Cited by 62 publications

(80 citation statements)

References 66 publications

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“…This might be due to higher global CK concentration in A. rhizogenestransformed roots as compared with nontransformed roots, which could mask a moderate NF-induced CK accumulation (only a 2-fold CK increase was reported by van Zeijl et al [2015] in response to NF in nontransformed roots in the absence of aminoethoxyvinylglycine). A possible candidate for the direct or indirect regulation of CK pathways is MtKNOX3, which we found here to be NF induced in the epidermis, in addition to being up-regulated in nodule primordia (Azarakhsh et al, 2015). KNOX genes are indeed known to control CK metabolism in the shoot apical meristem, and MtKNOX3-RNAi lines exhibit reduced expression of IPT, LOG and RRA genes involved in CK biosynthesis, activation and response respectively (Azarakhsh et al, 2015).…”

Section: Discussionmentioning

confidence: 75%

“…A possible candidate for the direct or indirect regulation of CK pathways is MtKNOX3, which we found here to be NF induced in the epidermis, in addition to being up-regulated in nodule primordia (Azarakhsh et al, 2015). KNOX genes are indeed known to control CK metabolism in the shoot apical meristem, and MtKNOX3-RNAi lines exhibit reduced expression of IPT, LOG and RRA genes involved in CK biosynthesis, activation and response respectively (Azarakhsh et al, 2015).…”

Section: Discussionmentioning

confidence: 75%

“…Among the latter was the predicted ortholog of AtLBD16, which regulates lateral root formation via direct activation by ARFs (Okushima et al, 2007). Interestingly, six homeodomain protein genes also were NF up-regulated, including MtKNOX3, a gene upregulated during nodulation and recently shown to act depending on CK pathways (Azarakhsh et al, 2015).…”

Section: Mt20120830mentioning

confidence: 99%

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A Laser Dissection-RNAseq Analysis Highlights the Activation of Cytokinin Pathways by Nod Factors in the Medicago truncatula Root Epidermis

et al. 2016

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Nod factors (NFs) are lipochitooligosaccharidic signal molecules produced by rhizobia, which play a key role in the rhizobiumlegume symbiotic interaction. In this study, we analyzed the gene expression reprogramming induced by purified NF (4 and 24 h of treatment) in the root epidermis of the model legume Medicago truncatula. Tissue-specific transcriptome analysis was achieved by laser-capture microdissection coupled to high-depth RNA sequencing. The expression of 17,191 genes was detected in the epidermis, among which 1,070 were found to be regulated by NF addition, including previously characterized NF-induced marker genes. Many genes exhibited strong levels of transcriptional activation, sometimes only transiently at 4 h, indicating highly dynamic regulation. Expression reprogramming affected a variety of cellular processes, including perception, signaling, regulation of gene expression, as well as cell wall, cytoskeleton, transport, metabolism, and defense, with numerous NF-induced genes never identified before. Strikingly, early epidermal activation of cytokinin (CK) pathways was indicated, based on the induction of CK metabolic and signaling genes, including the CRE1 receptor essential to promote nodulation. These transcriptional activations were independently validated using promoter:b-glucuronidase fusions with the MtCRE1 CK receptor gene and a CK response reporter (TWO COMPONENT SIGNALING SENSOR NEW). A CK pretreatment reduced the NF induction of the EARLY NODULIN11 (ENOD11) symbiotic marker, while a CK-degrading enzyme (CYTOKININ OXIDASE/DEHYDROGENASE3) ectopically expressed in the root epidermis led to increased NF induction of ENOD11 and nodulation. Therefore, CK may play both positive and negative roles in M. truncatula nodulation.

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 75%

Section: Mt20120830mentioning

confidence: 99%

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A Laser Dissection-RNAseq Analysis Highlights the Activation of Cytokinin Pathways by Nod Factors in the Medicago truncatula Root Epidermis

et al. 2016

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“…Three class 2 and two class 1 KNOXs, including one STM-like gene, are expressed in roots (Di Giacomo et al, 2008), suggesting a function for KNOX TFs in below-ground organs. Recently, overexpression of the class 2 MtKNOX3 gene was shown to trigger the formation of pseudo-nodules in P. sativum and M. truncatula (Azarakhsh et al, 2015), suggesting an involvement of KNOX genes in symbiotic nodule development. However, a specific KNOX3 RNA interference (RNAi)-mediated silencing did not reveal any root or nodule phenotype.…”

Section: Introductionmentioning

confidence: 99%

KNAT3/4/5‐like class 2 KNOX transcription factors are involved in Medicago truncatula symbiotic nodule organ development

et al. 2016

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We investigated the role of KNOX genes in legume root nodule organogenesis. Class 1 KNOX homeodomain transcription factors (TFs) are involved in plant shoot development and leaf shape diversity. Class 2 KNOX genes are less characterized, even though an antagonistic function relative to class 1 KNOXs was recently proposed. In silico expression data and further experimental validation identified in the Medicago truncatula model legume three class 2 KNOX genes, belonging to the KNAT3/4/5-like subclass (Mt KNAT3/4/5-like), as expressed during nodulation from early stages. RNA interference (RNAi)-mediated silencing and overexpression studies were used to unravel a function for KNOX TFs in nodule development. Mt KNAT3/4/5-like genes encoded four highly homologous proteins showing overlapping expression patterns during nodule organogenesis, suggesting functional redundancy. Simultaneous reduction of Mt KNAT3/4/5-like genes indeed led to an increased formation of fused nodule organs, and decreased the expression of the MtEFD (Ethylene response Factor required for nodule Differentiation) TF and its direct target MtRR4, a cytokinin response gene. Class 2 KNOX TFs therefore regulate legume nodule development, potentially through the MtEFD/MtRR4 cytokinin-related regulatory module, and may control nodule organ boundaries and shape like class 2 KNOX function in leaf development.

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“…Потеря функ-ции цитокининовых рецепторов у мутантов L. japonicus и M. truncatula приводит к подавлению клубенькообразо-вания. В то же время при развитии клубеньков у разных видов бобовых выявлена активация транскрипции генов, кодирующих компоненты передачи сигнала цитокини-нов -регуляторов ответа (RR) A и B типов (Gonzalez-Rizzo et al, 2006;Plet et al, 2011;Azarakhsh et al, 2015). Была установлена роль белков MtRR1 (RR В-типа) и MtRR4 (RR А-типа) в качестве позитивного и негативного регу-ляторов клубенькообразования, соответственно (Op den Camp et al, 2011;Ariel et al, 2012), причем ТФ MtRR1 непосредственно контролирует экспрессию гена MtRR4, образуя негативную обратную связь в этой системе (Ariel et al, 2012).…”

Section: галлы и опухоли: меристемы под ключ -заселение сегодняunclassified

Plant stem cells: unity and diversity

Додуева¹,

Tvorogova²,

Azarakhsh³

et al. 2016

Vestn. VOGiS

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Stem cells are undifferentiated cells of multicellular organisms that can divide, self-renew and differentiate. Despite the differences of properties, general principles of the existence of stem cells can be distinguished in all multicellular organisms. In plants, stem cells are found in meristems -the structures that ensure the continuous growth of plant and provide material for the formation of various specialized tissues. There are numerous types of meristems: shoot and root apical meristems, lateral meristems (procambium, cambium, pericycle), as well as the so-called irregular meristems, developing under certain conditions (callus, meristems of symbiotic nodules, spontaneous and pathogen-induced tumors, etc.). For each of meristems, specific mechanisms of regulation, which are based on the interaction of plant hormones and the major groups of transcription factors, were identified. The activity of meristems is based on two opposite processes: proliferation and self-renewal of stem cells in the central part of the meristem and differentiation of specialized cells in the periphery. WOX-CLAVATA systems are a regulatory component conservative for different meristems and providing consistency of the composition of the meristem, as well as the balance of stem cell proliferation and differentiation. In this review, we will consider the similarities and differences between the principles of organization of stem cell niches in plants and animals, as well as in a variety of meristems of higher plants; special attention will be paid to the role of WOX-CLAVATA systems in maintaining meristems and their interaction with other meristem regulators.Keywords: stem cells; meristems; WOX; CLE-peptides; LRR-kinases; apical meristems; cambium; pericycle; callus; tumors; nodules.Стволовые клетки -недифференцированные клетки многоклеточ-ных организмов, способные делиться, самообновляться и диф-фе ренцироваться. Несмотря на существующие различия свойств, у всех многоклеточных организмов можно выделить общие прин-ципы существования стволовых клеток. У растений стволовые клетки находятся в меристемах -структурах, обеспечивающих непрерывный рост растения и предоставляющих материал для образования различных специализированных тканей. Выделяют разнообразные типы меристем: апикальные -побега и кор ня, латеральные (прокамбий, камбий, перицикл), а также так называемые нерегулярные, развивающиеся при определен-ных усло виях (каллус, меристемы симбиотических клубеньков, спонтан ные и патоген-индуцированные опухоли и т. д.). Для каж-дой из меристем выявлены специфические механизмы регуля-ции, для которых характерно взаимодействие фитогормонов и основных групп транскрипционных факторов. Активность меристем обусловлена двумя противоположных процессами: пролиферацией и самообновлением стволовых клеток в цен-тральной части меристемы и дифференцировкой специализиро-ванных клеток на периферии. Системы WOX-CLAVATA -консерва-тивный для разных меристем регуляторный компонент, который обеспечивает размер и постоянство состава меристемы, а также баланс ...

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KNOTTED1-LIKE HOMEOBOX 3: a new regulator of symbiotic nodule development

Abstract: Highlight: KNOX3 gene is involved in symbiotic nodule development in Medicago truncatula and Pisum sativum, providing evidence that it may regulate cytokinin biosynthesis/activation upon nodulation.

Cited by 62 publications

References 66 publications

A Laser Dissection-RNAseq Analysis Highlights the Activation of Cytokinin Pathways by Nod Factors in the Medicago truncatula Root Epidermis

A Laser Dissection-RNAseq Analysis Highlights the Activation of Cytokinin Pathways by Nod Factors in the Medicago truncatula Root Epidermis

KNAT3/4/5‐like class 2 KNOX transcription factors are involved in Medicago truncatula symbiotic nodule organ development

Plant stem cells: unity and diversity

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