Comparative genomics of the two species of the genus Acanthostachys (Bromeliaceae): evolution of drought tolerance mechanisms

Abstract

Bromeliaceae are widely distributed in tropical and subtropical America. However, climate change and the consequent water scarcity in some regions have been risk warning factors for many of these species. Unfortunately, most of the global data on climate change in natural biological systems was collected at medium and high latitudes. Thus, the impacts of climate change on the flora of bromeliads in tropical regions remain largely undocumented. Epiphytic habit, absorptive trichomes, leaf succulence, acid metabolism of crassulaceae (CAM) and phenotypic plasticity are some of the adaptive characteristics present in the species of bromeliads. These adaptations allowed bromeliads to colonize a wide variety of environments, from humid forests to desert regions. However, the scarcity of sequenced bromeliads genomes makes it difficult to develop research aiming to discover these adaptive mechanisms. The project "Challenges for biodiversity conservation in the face of climate change, pollution and land use and occupation" (FAPESP 2017 / 5034-0) foresees the sequencing of the genome of the two species that make up the genus Acanthostachys. A. strobilacea and A. pticairnioides are bromeliads of epiphytic habit, which stand out for their tolerance to water deficit and high temperatures. Recent cytogenetics show that the genome of these two species is organized into 50 chromosomes, with flow cytometry analyzes estimating an average size of the diploid genome of approximately 350 Mb. Sequencing the genome of both species will generate genomic databases of public domain and make nuclear sequences available that will assist in the taxonomic delimitation of the genus. Comparative genomic and transcriptomic analyzes will contribute to the knowledge of the organization and regulation of the genes involved in the tolerance responses of these native species to environmental stresses, with potential for application to cultivated species of interest. Finally, the sequencing initiative can contribute to the preservation of species, especially A. pticairnioides, classified as vulnerable in the list of threatened species in ES and as data deficient in the list of CNCFlora.