Influence of Environmental Factors on the Genetic and Chemical Diversity of Brickellia veronicifolia Populations Growing in Fragmented Shrublands from Mexico

Abstract

<i>Brickellia veronicifolia</i> is a native Asteraceae from Mexico that persists in fragmented habitats. This investigation reports the genetic and chemical diversity of <i>B. veronicifolia</i>. The diversity analysis based on iPBS markers showed an averaged Shannon index (<i>S</i>) of 0.3493, a Nei genetic diversity (h) of 0.2256, and a percentage of polymorphic loci average (<i>P</i>) of 80.7867%. The population structure obtained by AMOVA revealed that the highest variation found within populations was 94.58%. GC-MS profiling of six populations indicated that major volatiles were β-caryophyllene (11.63%), spathulenol (12.85%), caryophyllene oxide (13.98%), α-cadinol (7.04%), cubedol (6.72%) and tau-muurolol (4.81%). Mantel tests suggested a statistically significant relationship between minor volatiles and geographical distance (<i>r</i> = 0.6163; <i>p</i> = 0.0470; <i>p</i> ˂ 0.05). Likewise, major volatiles showed a significant correlation with the soil pH (<i>r</i> = 0.6862; <i>p</i> = 0.0230) and maximum temperature (<i>r</i> = 0.4999; <i>p</i> = 0.0280). Our study suggests that the variation and genetic divergence of <i>B. veronicifolia</i> has no relationship with climatic parameters, whereas the volatiles are probably influenced by environmental factors and not by the genotype per se. Based on the characteristics of <i>B. veronicifolia</i>, this plant could be considered as a candidate for restoring fragmented shrublands in Mexico.