Diversité génétique des variétés d’arachides (Arachis hypogaea) en Algérie.

Abstract

The knowledge and characterization of plant genetic resources are major challenges for our country to protect and enhance our genetic heritage. Peanut (Arachis hypogaea L) is one of the cultivated plants with a narrow genetic base, hence the interest in prospecting, rescuing, and characterizing germplasm of this species. The present study aimed to assess, for the first time, the genetic diversity and population structure of Algerian peanut accessions originated from four geographic regions in the north and south of the country using 40 agro-morphological descriptors, 11 microsatellite markers and seed storage proteins. Findings showed a high genetic diversity between studied accessions for all the markers and confirmed the presence of two subspecies of A. hypogaea in the studied collection results confirm also the important role of conarachine I fraction to distinguished between these subspecies. Furthermore, PCA results were revealed that leaflet size (length and width), seed shape and size, oil content, and branching pattern were the principal characters to discriminate the screened A. hypogaea accessions. Besides that, molecular analysis was exhibited 86 alleles with a mean number of 7.545 alleles per locus. Genetic structure analysis showed a strong population at K=2, separating accessions according to their geographic origin (North and south) with some exceptions. Unweighted Pair Group Method with Arithmetic Averages (UPGMA) results were consistent with the results from the structure and PCA analysis dividing the studied collection into two clusters based on the subspecies affiliation of accessions. Moreover, Analysis of Molecular Variance (AMOVA) revealed high genetic variation within individuals (90.7%) and low genetic differentiation between subspecies (10,3%) and among populations (8.9%). On the other hand, peanut is accounted as one of the most cause of food allergy and anaphylaxis choc. Despite this, studies of peanut allergy didn’t make the subject of intensive interest in Algeria. The objective of this research, was to evaluate the allergenicity of six peanut accessions using Balb/c mouse model. Serum specific IgE, IgG and IgG1 antibodies against peanut proteins were presented a high level. Furthermore, the histological analysis of jejunal sections were showed a lot of damages and inflammatory cells infiltration. These results were traduced the success of sensitized protocol used. Findings reports also that accessions belonging to the subspecies hypogaea especially Timimoune and El Oued 1 were the most hypoallergenic accessions compared with those belonging to the fastigiata subspecies. During the different parts of this research Saharan Algerian peanut accessions were presented the best characteristics, namely agro-morphological traits and hypoallergenic character. Thus, we suggest the use of these accessions for cultivation and industry in order to benefit of their agronomical quality and fighting against peanut allergy problem.