Symbiosis‐related polypeptides associated with the early stages of ectomycorrhiza organogenesis in birch (Betula pendula Roth)

Abstract

SUMMARYAs a preliminary step towards elucidation of the molecular basis of ectomycorrhiza differentiation, polypeptide changes at different stages of mycorrhiza development were analyzed in birch {Betula pendula Roth). Timesequencing of the stages in the infection process of clonal plants inoculated with a compatible isolate of Paxillus involutus Batsch revealed that by 8 d mature ectomycorrhizas were obtained. Total phenol-extracted proteins of roots during the ' mycorrhiza formation stage' (2-8 d post-inoculation) were separated by two-dimensional polyacrylamide gel electrophoresis and the resulting patterns compared with non-mycorrhizal roots and mycelium. Alteration in the concentration of polypeptides from the host plant roots was limited even after 8 d of contact between the symbionts. However, seven novel polypeptides were detected 4 d after inoculation, three of them being already present m 2-d-old ectomycorrhizas. These findings demonstrate that symbiosis-related polypeptides accumulate in ectomycorrhizal roots prior to any of the morphological changes characterizing the symbiotic state.

Detection of symbiosis‐related polypeptides during the early stages of the establishment of arbuscular mycorrhiza between Glomus mosseae and Pisum sativum roots

“…Frisson. Furroot colonization, Dumas-Gaudot et al, 19946, thermore, in order to identify the SR-polypeptides, demonstrated a differential pattern of polypeptide a comparison was made between polypeptide profiles modifications, as previously reported for from G. mosseae-inoculated roots of the two folectomycorrhizas (Hilbert & Martin, 1988; Hilbert, lowing pea mutants, the P56 (myc"^, nod") and the P2 Costa & Martin, 1991;Simoneau et al, 1993;(myc~, nod"). Martin, Lapeyrie & Tagu, 1996 them were newly induced.…”

Protein biosynthesis changes during mycorrhiza formation in roots of micropropagated birch

“…Protein extraction and electrophoresis Protein were extracted, solubilized and separated by two-dimensional polyacrylamide gel electrophoresis as previously described (Simoneau et a/., 1993). Alter electrophoresis, gels were impregnated w~h Entensily (Du pont de Nemours S.A., Les Ulis, France), dried under vacuum, and autolluorographed w~h Kodak XAAS films at -7o•c.…”

“…eucalypt (isolate COU), poplar (isolate ANU, MAl), oak (isolate NAU), and aspen (isolate PEP), and cultured on a cellophane membrane in Petri dishes containing MMN solid medium (Marx, 1969). The mycorrhizas were synthesized and sampled as previously described (Simoneau et al, 1993). For in vivo labeling experiments, before sampling, free-living mycelium and roots of ectomycorrhizal and non inoculated plants were immersed in micropropagation medium containing 50 IJCilml of 35 S-methionine, incubated 4 h in the growth chamber at 23•c.…”

“…Using this model system, Hilbert et al (1991) have shown that symbiosis-related polypeptides accumulate in eucalypt roots challenged with an aggressive isolate of Pisolithus tinctorius while changes in polypeptide patterns were not observed in the roots treated with a non-aggressive one. Recently a similar approach was used to demonstrate that an accumulation of few polypeptides also occurs in developing synthetic birch ectomycorrhizas obtained by associating the roots of micropropagated clonal plants with the cctomycorrhizal fungus, Paxillus mvolutus (Simoneau et al, 1993). This symbiotic system, in which all the plants have exactly the same genetic background, represent a useful tool for the comparison of mycorrhizal efficiencies of various fungal isolates and subsequent analysis of the molecular events that accompany successful or unsuccessful root colonisation.…”

“…the mature mycorrhiza (Horan et al, 1988). Based on these observations the infection process has been divided in three stages called respectively "preinfection", "mycorrhiza-formation", and "mature mycorrhiza" Simoneau et al, 1993). The relative length of each stage may be modulated by varying degrees of aggressiveness of the fungal isolates toward the host plant roots.…”