Effect of host-applied Auxin on development of endomycorrhiza in cowpeas

Gunze, C.M.B.; Hennessy, C. M. R.

doi:10.1016/s0007-1536(80)80153-7

Cited by 24 publications

(4 citation statements)

References 12 publications

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“…A differential induction of IBA instead of IAA may contribute to the proper hyphal growth in colonized roots. In addition, it was shown that exogenous application of auxin increased the development of AM symbiosis (Gunze and Hennessy 1980). Also, treatment with the auxin transport inhibitor 2,3,5‐triiodobenzoic acid (TIBA) resulted in an increased colonization rate of Lablab purpureus roots with an AM fungus (Xie et al 1998) and an increased appressorium formation (Müller 1999).…”

Section: Discussionmentioning

confidence: 99%

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Jentschel

Thiel

Rehn

et al. 2007

Physiologia Plantarum

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Plant hormones, including auxins, might be signals during the establishment of an arbuscular mycorrhizal (AM) symbiosis. Here, we report on the concentrations of three auxins native to nasturtium (Tropaeolum majus L.) during early AM development. Indole‐3‐acetic acid (IAA), indole‐3‐butyric acid (IBA), and phenylacetic acid (PAA) were previously identified as endogenous compounds in this species by full‐scan gas chromatography–mass spectrometry. All auxinic compounds were influenced by AM colonization but showed completely different patterns. At very early stage, free IAA and IBA were lower in infected than in control roots, whereas PAA concentration was higher in infected roots than in controls. At later stages, PAA was reduced in colonized roots, whereas, especially, IBA was increased in colonized roots compared with controls. Measurement of total auxins confirmed a complex regulation pattern for the three compounds. In hyphae of Glomus intraradices, none of the auxins was detectable. Biosynthesis of the three auxins was measured using heavy labeled isotopes as precursors in control and AM‐inoculated roots. While not much difference was found in the IAA labeling pattern between controls and AM‐inoculated roots at both time points, IBA synthesis was slightly higher in AM‐inoculated roots. Double labeling experiments showed that two distinct pathways, a tryptophan‐dependent and a tryptophan‐independent biosynthetic pathway contribute to the synthesis of IAA in T. majus roots. Because T. majus is difficult to genetically manipulate, we have used tobacco plants transformed with the auxin‐inducible promoter GH3 fused to the β‐glucuronidase (GUS) reporter gene to investigate whether AM structures would co‐localize to cells harboring the auxin‐inducible promoter. Although the GUS activity increased significantly in AM‐inoculated roots, there was no obvious correlation between GH3::GUS expression and fungal structures.

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Section: Discussionmentioning

confidence: 99%

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Jentschel

Thiel

Rehn

et al. 2007

Physiologia Plantarum

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“…Exogenous application of IAA has been found to improve mycorrhizal development namely, arbuscule frequency (Gunze & Hennessy, 1980) and fungal colonization (Bareen et al ., 1988). Uninfected roots that had been treated with auxin showed morphological characteristics similar to those of mycorrhizal ones (Ludwig‐Müller, 2000), therefore it was suggested that auxins play an integral role in the symbiotic relationship (Meyer, 1974) .…”

Section: Discussionmentioning

confidence: 99%

Hormone concentrations in tobacco roots change during arbuscular mycorrhizal colonization with *Glomus intraradices**

et al. 2002

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Summary• Phytohormones are known to play a pivotal role in various developmental processes in plants and in arbuscular-mycorrhizal (AM) fungal-host symbiosis. This study focuses on characterizing the changes in the concentrations of auxins, cytokinins and gibberellins in tobacco ( Nicotiana tabacum ) during the early stages of colonization by Glomus intraradices , using advanced analytical detection techniques.• High-pressure liquid chromatography analysis followed by radioimmunoassay detection revealed that AM colonization induced the accumulation of specific zeatin riboside-like and isopentenyl adenosine-like compounds in both roots and shoots.• Use of the gas chromatography-mass spectrometry technique on the same developmental stage revealed that gibberellins (GA) of the earl-13-hydroxylation biosynthetic pathway (GA 1 , GA 8 , GA 19 and GA 20 ) were significantly more abundant in roots, but not shoots, of AM inoculated plants than in those of nonmycorrhizal plants. Indoleacetic acid concentrations (total and free) remained unaltered by AM colonization.• This study demonstrates that hormonal changes do occur during AM symbiosis with tobacco, before the fungal benefits manifest.

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“…Kaldorf & Ludwig-Müller (2000) observaram que a aplicação exógena de AIB altera a morfologia de raízes de milho da mesma maneira que a formação de MA. Tem sido demonstrado também que a aplicação exógena de auxina estimula o desenvolvimento de MAs (Gunze & Hennessy, 1980), e que o tratamento de raízes com ácido 2,3,5-triiodobenzóico (TIBA), um inibidor do transporte polar de auxinas que pode levar a seu acúmulo em certos tecidos, resulta em aumento da colonização de raízes de Lablab purpureus por Glomus mosseae (Xie et al, 1998).…”

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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Effect of host-applied Auxin on development of endomycorrhiza in cowpeas

Cited by 24 publications

References 12 publications

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Hormone concentrations in tobacco roots change during arbuscular mycorrhizal colonization with *Glomus intraradices**

Regulação do desenvolvimento de micorrizas arbusculares

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Effect of host-applied Auxin on development of endomycorrhiza in cowpeas

Cited by 24 publications

References 12 publications

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Arbuscular mycorrhiza enhances auxin levels and alters auxin biosynthesis in Tropaeolum majus during early stages of colonization

Hormone concentrations in tobacco roots change during arbuscular mycorrhizal colonization with Glomus intraradices*

Regulação do desenvolvimento de micorrizas arbusculares

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Hormone concentrations in tobacco roots change during arbuscular mycorrhizal colonization with *Glomus intraradices**