Hydroxyproline-rich glycoprotein mRNA accumulation in maize root cells colonized by an arbuscular mycorrhizal fungus as revealed by in situ hybridization

The arbuscular mycorrhizal fungus Glomus mosseae is able to confer bioprotection against Phytophthora parasitica in tomato roots. Localized and induced systemic resistance (ISR) have been demonstrated to be involved in pathogen control in mycorrhizal and nonmycorrhizal roots with a split root experimental system. Decreased pathogen development in mycorrhizal and nonmycorrhizal parts of mycorrhizal root systems is associated with accumulation of phenolics and plant cell defense responses. G. mosseae-containing cortical cells in the mycorrhizal tissues are immune to the pathogen and exhibit a localized resistance response with the formation of cell wall appositions reinforced by callose adjacent to intercellular hyphae. The systemically induced resistance in nonmycorrhizal root parts is characterized by elicitation of host wall thickenings containing non-esterified pectins and PR-1a protein in reaction to intercellular pathogen hyphae, and by the formation of callose-rich encasement material around P. parasitica hyphae that are penetrating root cells. PR-la protein is detected in the pathogen wall only in these tissues. None of these cell reactions are observed in nonmycorrhizal pathogen-infected root systems, where disease development leads to host cell death. The cellular and molecular basis of bioprotection by an arbuscular mycorrhizal fungus is discussed in relation to that induced by other nonpathogenic microorganisms.

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Transcription of a Gene Encoding a Lectinlike Glycoprotein Is Induced in Root Cells Harboring Arbuscular Mycorrhizal Fungi in Pisum sativum

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1999.12.9.785 ◽

1999 ◽

Vol 12 (9) ◽

pp. 785-791 ◽

Cited By ~ 17

Author(s):

Raffaella Balestrini ◽

Silvia Perotto ◽

Elena Gasverde ◽

Preeti Dahiya ◽

Lise-Lotte Guldmann ◽

...

Keyword(s):

In Situ Hybridization ◽

Mycorrhizal Fungi ◽

Root Nodules ◽

Arbuscular Mycorrhizal ◽

Pcr Primers ◽

Root Cells ◽

Hybridization Probes ◽

Mycorrhizal Roots ◽

Pea Roots

The gene PsNlec1, which encodes a lectinlike glycoprotein, is strongly expressed in pea nodule tissue. Using gene-specific polymerase chain reaction (PCR) primers, in situ hybridization probes, and specific antisera derived from the PsNlec1 sequence, we investigated gene expression associated with the arbuscular mycorrhizal (AM) symbiosis of pea roots. With the use of reverse transcription (RT)-PCR and cold in situ hybridization, strong expression of the transcript was demonstrated not only in root nodules but also in mycorrhizal roots when the cells were colonized by the endomycorrhizal fungus Glomus versiforme. No transcript was detectable in uninfected pea roots. With an antiserum raised against PsNLEC-1 polypeptide, a single antigenic band (25 kDa) was observed following gel electrophoresis of extracts from mycorrhizal roots. However, the amount of antigen was apparently too low to be detected by immunogold localization in tissue sections of pea mycorrhizal roots.

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