RVVS 2013

Chimerism and genetic diversity within the cultivar group of pinots

Three clones of Vitis vinifera cv. pinot gris were analysed at 50 microsatellite loci to assess the presence of intra-varietal genetic variability. Two clones revealed a polymorphism expressed by the presence of three alleles at 5 loci instead of the two expected for a diploid species. By sequencing the three alleles amplified at two loci, we confirm that they correspond to different allelic states of the same locus but differ in their number of repeat units. Such tri-allelic profiles could reveal periclinal chimeras in which the two cell layers of the apical meristem are genetically different. For two clones, this periclinal chimeric state has been deduced from the comparison of the genoty…

Sampling strategy in molecular microbial ecology: influence of soil sample size on DNA fingerprinting analysis of fungal and bacterial communities.

Assessing soil microbial community structure by the use of molecular techniques requires a satisfactory sampling strategy that takes into account the high microbial diversity and the heterogeneous distribution of microorganisms in the soil matrix. The influence of the sample size of three different soil types (sand, silt and clay soils) on the DNA yield and analysis of bacterial and fungal community structure were investigated. Six sample sizes from 0.125 g to 4 g were evaluated. The genetic community structure was assessed by automated ribosomal intergenic spacer analysis (A-RISA fingerprint). Variations between bacterial (B-ARISA) and fungal (F-ARISA) community structure were quantified b…