Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Oral Communication Abstract - S5h

THE EFFECT OF ABIOTIC STRESS ON NATURAL POPULATIONS STRUCTURE: ANALYSIS USING MOLECULAR MARKERS TARGETED TO STRESS-INDUCIBLE GENES

JONES-EVANS E., MAESTRI E., MARMIROLI N.

Division of Genetics and Environmental Biotechnology, Department of Environmental Sciences, University of Parma, Italy

AP-PCR, abiotic stress, tolerance, antimony

The presence of heavy metals in soils is a recurring problem, resulting both from anthropogenic industrial activities and as a natural phenomenon. The toxic conditions found on these soils influence on the biomass production and reproductive capacity of plants in a negative way, as well as exerting strong selective pressures. A number of species however have evolved mechanisms to tolerate these extreme conditions and have colonised contaminated soils. Molecular markers generated by the AP-PCR (Arbitrary Primed-Polymerase Chain Reaction) technique were employed to asses the genetic variability within and among populations of three plant species, Achillea ageratum, Plantago lanceolata and Inula viscosa, growing around a disused antimony mine, in order to gain an insight into how natural populations behave under stressful conditions. Primers (19-21nt) were designed on conserved coding sequences of stress responsive genes such as metallothioneins groups 1 and 2, phytochelatin synthase using Arabidopsis and tomato gene sequences for primer design. As these molecular markers are gene-targeted, they will be subjected to selection and hence valuable information on the genetic structure of populations subjected to abiotic stress can be gleaned. Results show that in each species, a small but significant proportion of genetic variation was attributed to differences among populations, in A. ageratum in particular. In I. viscosa and P. lanceolata, populations sampled from the most contaminated site show significantly less genetic variability with respect to the control population (from an area of low contamination) indicating an effect due to the contaminant. Principal Coordinates Analysis of a matrix of genetic distance values among pairs of individuals showed that individuals from the same population clustered together. Moreover a significant correlation was seen between environmental parameters and specific loci.