Symbiotic Fungi: Principles and Practice (Soil Biology)

15 Functional Genomic of Arbuscular Mycorrhizal Symbiosis 267
and Table 15.13), with seven and 12 spots whose abundance were decreased and
increased in G. mosseae-inoculated roots respectively. All of them were excised
from a micropreparative Coomassie Blue-stained gel and subjected to PMF search
following MALDI-TOF spectrometry. Among the 13 proteins, only 11 spots could
be excised from the gel. Six out of these 11 spots, indicated by asterisks in Table
15.13, gave positive hits after PMF search.
Five ribosomal genes have been previously reported as being over-expressed at
the transcript level, among which four were predicted to encode proteins potentially
located on 2-DE gels after in silico analysis. When these spots were submitted to
PMF search, only spot 11* was confirmed as being a ribosomal protein. None of the
other predicted proteins (spots 3*, 5*, 6* and 7*) could be confirmed. Instead of the
in silico-predicted proteins, a probable peroxidase, a guanine nucleotide binding
protein, a probable peroxidase precursor and a probable GTP-binding protein were
identified (Table 15.13).
Spots 3* and 6*, whose amount increased in response to G. mosseae inoculation,
gave hits with a probable peroxidase (MtC40023) and a probable peroxidase
precursor (MtC10717). Since the first publication of Spanu and Bonfante-Fasolo
(1988) several groups have reported an increase of peroxidase activities in response
Table 15.13 Proteins differentially displayed upon Glomus mosseae inoculation of Medicago
truncatula roots
Spot a Accession
number
Matched peptide
number
Coverage/score Identification
1 MtC00229 7 48%/3.28e + 003 Alanine aminotransferase
2 MtC50061 6 23%/9.13e + 003 Serine/threonine kinase
3 b
MtC40023 10 40%/2.13e + 004 Probable peroxidase
4 MtC00294 10 38%/5.29e + 004 Chalcone reductase
5 b
MtC00498 9 40%/2.37e + 005 Guanine nucleotide binding protein
6 b
MtC10717 10 34%/8.46e + 004 Probable peroxidase precursor
7 b
MtC00087 12 71%/2.01e + 006 Probable GTP-binding protein
8 MtC00681 8 25%/3.02e + 004 Glutathione-S-transferase
9 b
MtC10018 20 70%/1.79e + 005 Probable GST
10 – – – Nd
11 b
MtC00128 12 41%/1e + 005 40 S ribosomal protein S5
12 – – – Nd
13 – – – Nd
14 – – – Nd
15 – – – Nd
16 – – – Nd
17 – – – Nd
18 – – – Nd
19 – – – Nd
a
Numbers correspond to those in Fig. 1
b
Indicates proteins which were deduced from in silico analyses of ESTs over-expressed in
response to mycorrhizal inoculation (Weidmann et al. 2004)
Nd no protein identification was obtained after MALDI-TOF analysis and PMF search