Evidências de poliploidia e estruturação genética de Psidium brownianum(MYRTACEAE)em áreas de caatinga e cerrado

Abstract

Psidium species are distributed throughout the national territory. Due to its distribution, these species are found in the most varied types of biomes, being considered an excellent colonizer of environments. Tolerance and colonization of adverse environments in Psidium has been attributed to polyploidy, a recurrent event in the group. Despite this diversity, most studies on Psidium are related to species with wide distribution or that have economic importance, little is known about species that have a restricted distribution as in the case of P. brownianum that occurs in limited regions. Therefore, the objective of this work was to infer the DNA content of populations and understand the diversity and genetic structure of P. brownianum in Caatinga and Cerrado biomes. The results showed that populations had DNA content ranging from 2C= 1.87 pg to 2C= 2.92 pg. In addition to the DNA content, the results of the capillary electrophoresis analysis showed evidence of polyploidy in P. brownianum. The diversity indices showed that the population of MAR and MDC had the highest values ​​(Shannon Index 2.70; Simpson Index 0.93) for both populations. The analysis of multilocus genotypes (MLG) showed that populations do not have clones and very likely reproduce by sexual reproduction. The global Nei Gst showed that populations have a high diversity among them (0.15). The AMOVA result showed a greater variation within populations (68.75%). Structure analysis showed the formation of two Bayesian clusters (K=2) while DAPC analysis separated populations into five Bayesian clusters (K=5). The results showed that polyploidy is a common event among Psidium species, but in the case of P. brownianum, classical cytogenetic data would be needed to confirm the hypothesis. Furthermore, the use of molecular markers proved to be an efficient tool for population studies, showing that P. brownianum populations have a high diversity and genetic structure.