Endocellulase activity is associated with arbuscular mycorrhizal spread in pea symbiotic mutants but not with its ethylene content in root

Phytohormones are thought to mediate plant-arbuscular mycorrhizal (AM) interactions. To explore the role of phytohormones in the interaction between Nicotiana attenuata and Glomus intraradices, we analysed levels of jasmonic acid (JA) and its amino acid conjugate JA-isoleucine/JA-leucine (JA-Ile), salicylic acid (SA) and ethylene in either infected or non-infected N. attenuata wild-type (WT) plants growing in soils that mimic the nutrient supply rates found in the plant's native environment. Under these conditions, the infection decreases plant growth and reproductive performance. Levels of JA, JA-Ile and SA did not change upon infection, but ethylene release was slightly decreased. Transgenic N. attenuata plants defective in JA signalling (aslox3 and ircoi1) did not differ significantly in growth or reproductive performance compared with infected WT. Furthermore, no difference in infection rates could be observed. Transgenic plants unable to produce (iraco) or perceive (etr1) ethylene showed significantly larger decreases in growth and number of seed capsules produced between infected and non-infected plants compared with WT plants. We conclude that ethylene, rather than JA, signalling plays a role in the interaction between N. attenuata and AM, from which the plant does not realize a fitness benefit.

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“…2000; Herrera‐Medina et al. 2007), although in some plant–fungus systems ethylene levels were not altered (Morales Vela et al. 2007).…”

Section: Discussionmentioning

confidence: 99%

Symbiosis between Nicotiana attenuata and Glomus intraradices: ethylene plays a role, jasmonic acid does not

Riedel

Groten

Baldwin³

2008

Plant Cell & Environment

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“…The relationship between endogenous ET level in roots and the mycorrhizal behavior is also not always clear: (i) negative correlation was observed within pea E107 (brz) (Resendes et al, 2001; Morales Vela et al, 2007) or in ABA-deficient notabilis and sitiens tomato mutant plants (Herrera-Medina et al, 2007; Martín-Rodríguez et al, 2010); and (ii) even more confusing, a positive correlation between endogenous ET root content and mycorrhization was noticed in both, ET-overproducing ( epinastic ) and ET-deficient ( rin ) tomato mutants, while harboring curiously, respectively, lower and higher ET content compared to the wild type (Torres de Los Santos et al, 2016).…”

Section: Phytohormones Influence the Mycorrhizal Symbiosismentioning

confidence: 99%

“…This suggests an antagonistic interaction between ABA and ET. ET was also shown to be negatively regulated by BR (Morales Vela et al, 2007), and ET-insensitive ein2 mutant harbored reduced GA but elevated IAA levels (Foo et al, 2016). This corresponds with another study showing that application of 1-aminocyclopropane carboxylic acid (ACC), a precursor of ET, decreases free IAA content in roots (Negi et al, 2010).…”

Section: Phytohormones Influence the Mycorrhizal Symbiosismentioning

confidence: 99%

Unraveling the Initial Plant Hormone Signaling, Metabolic Mechanisms and Plant Defense Triggering the Endomycorrhizal Symbiosis Behavior

Bedini¹,

Mercy²,

Schneider³

et al. 2018

Front. Plant Sci.

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Arbuscular mycorrhizal (AM) fungi establish probably one of the oldest mutualistic relationships with the roots of most plants on earth. The wide distribution of these fungi in almost all soil ecotypes and the broad range of host plant species demonstrate their strong plasticity to cope with various environmental conditions. AM fungi elaborate fine-tuned molecular interactions with plants that determine their spread within root cortical tissues. Interactions with endomycorrhizal fungi can bring various benefits to plants, such as improved nutritional status, higher photosynthesis, protection against biotic and abiotic stresses based on regulation of many physiological processes which participate in promoting plant performances. In turn, host plants provide a specific habitat as physical support and a favorable metabolic frame, allowing uptake and assimilation of compounds required for the life cycle completion of these obligate biotrophic fungi. The search for formal and direct evidences of fungal energetic needs raised strong motivated projects since decades, but the impossibility to produce AM fungi under axenic conditions remains a deep enigma and still feeds numerous debates. Here, we review and discuss the initial favorable and non-favorable metabolic plant context that may fate the mycorrhizal behavior, with a focus on hormone interplays and their links with mitochondrial respiration, carbon partitioning and plant defense system, structured according to the action of phosphorus as a main limiting factor for mycorrhizal symbiosis. Then, we provide with models and discuss their significances to propose metabolic targets that could allow to develop innovations for the production and application of AM fungal inocula.

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“…O etileno difundido através dos espaços intercelulares poderia agir como um sinal regulador da expressão de genes codificando enzimas envolvidas na degradação das paredes celulares da planta e do fungo, como glucanases e quitinases. A relação entre o teor de ET e a atividade de endocelulases foi analisada em mutantes simbióticos de ervilha inoculados com G.mosseae (Morales-Vela et al, 2007). Os resultados mostraram que o aumento de atividade das endoglucanases e exoglucanases está associado à penetração da epiderme, ao crescimento da hifa através do córtex e da formação dos arbúsculos.…”

Section: Regulação Por Fitormôniosunclassified

“…Os resultados mostraram que o aumento de atividade das endoglucanases e exoglucanases está associado à penetração da epiderme, ao crescimento da hifa através do córtex e da formação dos arbúsculos. Porém, a produção de etileno não apresentou alterações nas raízes micorrizadas dos diferentes mutantes analisados (Morales-Vela et al, 2007). É possível que o conteúdo de ET seja importante para manter a atividade basal das endocelulases, no entanto a relação entre o teor de ET e o aumento da atividade das celulases em raízes micorrizadas, quando comparadas com raízes não-micorrizadas, não foi demonstrada (Morales-Vela et al, 2007).…”

Section: Regulação Por Fitormôniosunclassified

Regulação do desenvolvimento de micorrizas arbusculares

Kiriachek¹,

Azevedo²,

Peres³

et al. 2009

Rev. Bras. Ciênc. Solo

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RESUMOAs micorrizas arbusculares (MAs) são associações simbióticas mutualistas entre fungos do filo Glomeromycota e a maioria das plantas terrestres. A formação e o funcionamento das MAs depende de um complexo processo de troca de sinais, que resulta em mudanças no metabolismo dos simbiontes e na diferenciação de uma interface simbiótica no interior das células das raízes. Os mecanismos que regulam a formação das MAs são pouco conhecidos, mas sabe-se que a concentração de fosfato (P) na planta é um fator determinante para o desenvolvimento da simbiose. A disponibilidade de P na planta pode afetar o balanço de açúcares e de fitormônios (FHs), além da expressão de genes de defesa vegetal. Com o advento da genômica e proteômica, vários genes essenciais para o desenvolvimento das MAs já foram identificados e seus mecanismos de regulação estão sendo estudados. Até o presente, sabe-se que as plantas secretam substâncias que estimulam a germinação de esporos e o crescimento de fungos micorrízicos arbusculares (FMAs). Há evidências também de que os FMAs sintetizam moléculas sinalizadoras, que são reconhecidas pelas plantas hospedeiras. Pelo menos três genes são essenciais para o reconhecimento dessa molécula e a transdução do sinal molecular. Discutem-se os papéis desses genes e os possíveis mecanismos que regulam sua expressão, bem como os papéis dos FHs na regulação de MAs são discutidos.Termos de indexação: micorriza arbuscular, sinalização, fitormônios, genes de defesa, fosfato.(1) Recebido para publicação em junho de 2008 e aprovado em novembro de 2008.

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Endocellulase activity is associated with arbuscular mycorrhizal spread in pea symbiotic mutants but not with its ethylene content in root

Cited by 12 publications

References 56 publications

Symbiosis between Nicotiana attenuata and Glomus intraradices: ethylene plays a role, jasmonic acid does not

Symbiosis between Nicotiana attenuata and Glomus intraradices: ethylene plays a role, jasmonic acid does not

Unraveling the Initial Plant Hormone Signaling, Metabolic Mechanisms and Plant Defense Triggering the Endomycorrhizal Symbiosis Behavior

Regulação do desenvolvimento de micorrizas arbusculares

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