CONICET | Buscador de Institutos y Recursos Humanos

Dry forests, characterized by seasonal rainfall, are exposed to prolonged drought periods and high temperatures throughout theyear, with the consequent restricted water availability. Organisms occurring in these environments must develop strategies to copewith drought stress; thus, local adaptations likely play a crucial role in these biomes. In South America, the largest contiguousxerophytic forests are found in the Chaco ecoregion, where Neltuma species (previously classified within Prosopis) play significantecological and economic roles. However, no previous studies have assessed neutral and adaptive genetic variation across the distributionrange of these species. This study evaluated the genetic patterns of geographically distant Neltuma alba populations, by comparingputative neutral simple sequence repeats (SSRs) with putative adaptive expressed sequence tags (EST-SSRs) derived from transcriptomesequencing, and their relationship with climatic factors. Our results revealed moderate genetic diversity and low genetic differentiationamong populations. Notably, genetic structure varied with the type of marker, indicating different underlying evolutionary processesbetween them. The most important climatic gradient in the study area, defined by the eastwest variation in precipitation and diurnaltemperature range, could result in selective pressures on N. alba. This gradient might shape the genetic structure retrieved by the ESTSSRs and might be associated with leaf morphological patterns previously studied. The genetic diversity pattern of putative neutralmarkers was associated with geographic distances among populations but not with the climatic gradient. Our findings indicate that N.alba genetic diversity is inf luenced by two main factors: isolation by distance, whereby nearby populations tend to share more geneticdiversity, and local adaptation, which arises from different selective pressures linked to the climatic gradient. Our results are discussedconcerning their potential contribution to the management and conservation of this emblematic species of South American dry forests,which are facing landscape transformation and global climate change

enviar mensaje