Microsatellite analysis of genetic diversity in Indian chicken populations [Анализ генетической изменчивости внутри и между шестью индийскими популяциями кур с помощью микросателлитных маркеров. (Иран. Индия)]

Characterization of genetic diversity by employing molecular tools is a prerequisite in developing strategies for conservation and utilization of poultry genetic resources. We assessed genetic variation within and between six Indian chicken populations (Naked Neck, White Silkies, Commercial Layer and Broiler, Giriraja and Desi) using nine microsatellite markers. Seven loci were polymorphic in all populations, with the number of alleles varying from 3 to 27 per locus and 4.1 to 8.6 per population. Average heterozygosity and gene diversity in the populations were 0.68 and 0.66, respectively. Some populations and loci deviated from Hardy-Weinberg equilibrium. Except Naked Neck, none of other populations was in genotypic disequilibrium for a single pairwise locus combination. F-statistics indicated that populations are genetically structured, ∼85% of the total genetic variation being due to genetic differentiation within the populations. Estimates of Latter’s FST and Nei’s DS genetic distances revealed relatively close genetic similarity between Naked Neck and Giriraja, while White Silkies was the most distant. An estimated divergence time between Naked Neck and Giriraja was over 100 years, with a comparatively longer (over 450 years) period of separation between Giriraja and White Silkies. We suggest that there is an essential room left for genetic improvement of Indian native breeds and commercial stocks

Fungal cell wall phosphomannans facilitate the toxic activity of a plant PR-5 protein

9 pages, 6 figures, 1 table, 35 references.Osmotin is a plant PR-5 protein. It has a broad spectrum of antifungal activity, yet also exhibits specificity for certain fungal targets. The structural bases for this specificity remain unknown. We show here that full sensitivity of Saccharomyces cerevisiae cells to the PR-5 protein osmotin is dependent on the function of MNN2, MNN4 and MNN6. MNN2 is an α-1,2-mannosyltransferase catalyzing the addition of the first mannose to the branches on the poly l,6-mannose backbone of the outer chain of cell wall N-linked mannans. MNN4 and MNN6 are required for the transfer of mannosylphosphate to cell wall mannans. Null mnn2, mnn4 or mnn6 mutants lack phosphomannans and are defective in binding osmotin to the fungal cell wall. Both antimannoprotein antibody and the cationic dye alcian blue protect cells against osmotin cytotoxicity. MNN1 is an α-1,3-mannosyltransferase that adds the terminal mannose to the outer chain branches of N-linked mannan, masking mannosylphosphate. Null mnn1 cells exhibit enhanced osmotin binding and sensitivity. Several cell wall mannoproteins can bind to immobilized osmotin, suggesting that their polysaccharide constituent determines osmotin binding. Our results demonstrating a causal relationship between cell surface phosphomannan and the susceptibility of a yeast strain to osmotin suggest that cell surface polysaccharides of invading pathogens control target specificity of plant PR-5 proteins.This work was supported by a Spanish Government Fellowship (J.I.I.), NSF Award No. 9808551-MCB and USDA Cooperative award No. 58-6435-8-094.Peer reviewe