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In long-lived species, deforestation can modify the genetic diversity patterns of recent populations. The spatial-structure genetics of Pinus leiophylla Schiede ex Schltdl. & Cham. was investigated in adults and seedlings of remnant populations from central Mexico. Two chloroplast intergenic regions were sequenced of two cohorts (adults and seedlings) of 121 individuals of P. leiophylla from three localities. Higher genetic differentiation was found in adults (ФST = 0.09) than in seedlings (ФST = 0.03). The discriminant analysis of principal components detected four genetic clusters and the Mantel test found a weak but significant isolation by distance pattern (r2 = 0.05, p = 0.002). Sixteen percent of genetic variation was explained by the spatial component according to the genetic neighborhood analysis. And the effect of three landscape features, i.e., elevation, aspect (sine and cosine), and land use, explored with ResistanceGA, detected that land use significantly restricts gene flow between populations, mostly in the farming category. This study emphasizes the critical role of preserving forest cover to maintain connectivity among remnants of P. leiophylla. Insights of this study will contribute to the conservation of conifers in Mexican temperate forests, especially within landscapes heavily altered by human activities. [ABSTRACT FROM AUTHOR]

In this research, physiological tests were carried out on the in vitro growth of four strains of ectomycorrhizal fungi (HECM) associated with Pinus leiophylla. The HECM strains were subjected to growth tests in different concentrations of glucose (10, 20, 30 and 40 g/L) and nitrogen sources (KNO3, (NH4)2HPO4 and urea). The variables of growth, final diameter, biomass, mean growth rate and biomass/area ratio were evaluated in the colonies. According to the statistical analysis, the Suillus pseudobrevipes strain (GF3246) presented a higher growth in the concentrations of glucose 20 and 30 (g/L); S. pseudobrevipes (GF3285) in KNO3 and (NH4)2HPO4; S. subtomentosus (GF3331) in 20 and 40 (g/L) and in S. variegatus (GF3349) the growth was indistinct among the treatments. The HECM strains presented different growth strategies according to their ability to explore, exploit and assimilate different nutrients. Due to the fact that the strains GF3246 and GF3349 presented higher of values biomass in low to medium concentrations of glucose and nitrogen sources, they are considered generalists and were selected to produce mycelial inoculum and induce mycorrhization and to evaluate their effectiveness on the survival and growth of Pinus leiophylla seedlings. [ABSTRACT FROM AUTHOR]