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Published on: August 24, 2015
Pre-Penetration Apparatus Formation During AM Infection is Associated With a Specific Transcriptome Response in
Valeria Siciliano1, Andrea Genre, Raffaella Balestrini
1Dipartimento di Biologia Vegetale; Università di Torino and Istituto Protezione Piante-CNR; Torino, Italy.
Abstract:
Arbuscular mycorrhizal (AM) associations have strikingly constant structural and functional features, irrespectively of the organisms involved. This suggests the existence of common genetic and molecular determinants. one of the most important characteristics of AMs is the coating of intracellular hyphae by a proliferation of the plant plasma membrane, which always segregates the fungus in an apoplastic interface. This process of intracellular accommodation causes a dramatic reorganization in the host cell cytoplasm, which reaches its peak with the development of the so-called prepenetration apparatus (PPA), a specialised aggregation of organelles described in epidermal cells and predicting fungal development within the cell lumen. We have recently correlated PPA development with the significant regulation of 15 Medicago truncatula genes. Among these, a nodulin-like and an expansin-like sequence are good candidates as molecular markers of epidermal cell responses to AM contact. our results also suggest a novel role for the kinase DMI3 in enhancing the upregulation of these two genes and downregulating defence-related genes such as the Avr9/Cf-9 rapidly elicited protein 264. We here comment on these recent findings and their possible outcomes.
Insights
Arbuscular mycorrhizal (AM) symbiosis involves plant plasma membrane proliferation. This study identifies key genes and a kinase involved in plant cell responses to AM fungi.
Area of Science:
- Plant biology
- Mycology
- Molecular genetics
Background:
- Arbuscular mycorrhizal (AM) symbiosis exhibits conserved traits across species, suggesting shared genetic underpinnings.
- A key feature of AM symbiosis is the plant plasma membrane enclosing intracellular fungal hyphae, creating an apoplastic interface.
- This process involves significant host cell cytoplasmic reorganization, culminating in the prepenetration apparatus (PPA).
Purpose of the Study:
- To investigate the molecular mechanisms underlying plant cell responses during AM symbiosis.
- To identify host genes regulated by AM fungal contact and PPA development.
- To elucidate the role of specific plant kinases in mediating these responses.
Main Methods:
- Gene expression analysis in Medicago truncatula during AM colonization.
- Correlation of PPA development with the regulation of host genes.
- Investigating the role of the DMI3 kinase in gene regulation.
Main Results:
- Fifteen Medicago truncatula genes were significantly regulated during PPA development.
- Nodulin-like and expansin-like sequences emerged as potential molecular markers for plant cell responses to AM contact.
- The kinase DMI3 was implicated in upregulating these marker genes and downregulating defense-related genes.
Conclusions:
- The study highlights specific molecular players in plant-fungal interactions during AM symbiosis.
- Identified genes and DMI3 kinase offer insights into the genetic control of symbiotic development.
- Findings contribute to understanding the molecular dialogue between plants and arbuscular mycorrhizal fungi.
