Evolution of mitochondrial SSU-rDNA variable domain sequences and rRNA secondary structures, and phylogeny of the Agrocybe aegerita multispecies complex.

Mitochondrial small subunit (mtSSU) rDNA variable (V1, V2, V4, V6, V8 and V9) domain sequences and rRNA secondary structures evidenced eight molecular groups within 32 strains of the Agrocybe aegerita multispecies complex from different continents. mtSSU-rRNA secondary structure evolution occurred mainly by insertion/deletion of sequences from 8 to 57nt long. Preferential insertion/deletion sites correlated with loops of the mtSSU-rRNA secondary structures, and suggested that these events occurred in regions without interactions in the ribosomal-protein assembly.

A CAPS test allowing a rapid distinction of Penicillium expansum among fungal species collected on grape berries, inferred from the sequence and secondary structure of the mitochondrial SSU-rRNA.

Penicillium expansum is a fungal species highly damageable for the postharvest conservation of numerous fruits. In vineyards, this fungus is sometimes isolated from grape berries where its presence may lead to the production of geosmin, a powerful earthy odorant, which can impair grapes and wines aromas. However, the discrimination of P.

The mitochondrial apocytochrome b genes of two Agrocybe species suggest lateral transfers of group I homing introns among phylogenetically distant fungi.

The Agrocybe chaxingu and Agrocybe aegerita mitochondrial apocytochrome b coding sequences are highly similar (97% of nt identity), but have highly different sizes (2312 and 4867nt, respectively), due to the presence of three large group IB introns: two (iAae1 and iAae2) in A. aegerita, one (iAch1) in A. chaxingu.

Characterization of Penicillium species isolated from grape berries by their internal transcribed spacer (ITS1) sequences and by gas chromatography-mass spectrometry analysis of geosmin production.

Geosmin (trans-1,10-dimethyl-trans-9-decalol), an earthy-musty compound, has been identified in wines and in grape juice, in which its presence is highly detrimental to the aromatic quality. Geosmin has a biological origin, and the analysis of rotten grape microflora has been done on two grape varieties (Semillon, Cabernet Sauvignon) from six parcels of the Bordeaux region over 3 years (1999, 2000, 2001). Forty-three Penicillium-related species have been analyzed by gas chromatography-mass spectrometry (GC-MS) for their geosmin production.

Secondary structure and molecular evolution of the mitochondrial small subunit ribosomal RNA in Agaricales (Euagarics clade, Homobasidiomycota).

The complete sequences and secondary structures of the mitochondrial small subunit (SSU) ribosomal RNAs of both mostly cultivated mushrooms Agaricus bisporus (1930 nt) and Lentinula edodes (2164 nt) were achieved. These secondary structures and that of Schizophyllum commune (1872 nt) were compared to that previously established for Agrocybe aegerita. The four structures are near the model established for Archae, Bacteria, plastids, and mitochondria; particularly the helices 23 and 37, described as specific to bacteria, are present.

The Aa-Pri4 gene, specifically expressed during fruiting initiation in the Agrocybe aegerita complex, contains an unusual CT-rich leader intron within the 5' uncoding region.

The Aa1-Pri4 gene was cloned from the edible mushroom Agrocybe aegerita. The gene, specifically expressed during fruiting initiation, encodes a glycine-rich protein of 116 amino acids, with no homology to already known proteins. Homologous genes were amplified from two other strains belonging to the Agr.

Molecular characterization of the Pri3 gene encoding a cysteine-rich protein, specifically expressed during fruiting initiation within the Agrocybe aegerita complex.

Coding and regulating sequences of Pri3 (a novel gene specifically expressed in both nucleus types of dikaryons during fruiting initiation) were compared within nine strains of the Agrocybe aegerita complex originating from Europe, Asia and Latin America. Highly homologous coding sequences were found; and the 95-amino-acid-long PRI3 deduced proteins all shared eight cysteines and eight glycines, a putative signal peptide suggesting an extra-cellular localization, a protein kinase C site (T(70)) and a cAMP-dependent kinase site (S(74)). The PRI3 proteins presented no significant homologies with already known proteins and constitute a new class of small cysteine-rich proteins.

Phylogenetic relationships of Pleurotus species according to the sequence and secondary structure of the mitochondrial small-subunit rRNA V4, V6 and V9 domains.

A comparative study of the V4, V6 and V9 domains of the mitochondrial small-subunit (SSU) rRNA was conducted to evaluate the use of these sequences to investigate phylogenetic relatedness within the genus Pleurotus. The PCR products encompassing these regions from 48 isolates belonging to 16 Pleurotus species were sequenced and compared. From this comparison, the length and sequence of the three domains were found to be constant within a species.