Genetic diversity by ISSR of two endemic quillworts (Isoetes L.) species from Amazon Iron Rocky Outcrops, Isoetes cangae e I. serracarajensis

Two lycophyte endemic species have been recently described at the State of Para, in the Amazon forest located in the North of Brazil. Genetic diversity and population structure of Isoetes cangae and I. serracarajensis were investigated through ISSR molecular markers. These analyses aim to establish strategies for future attempts for species conservation. From sixteen primers, 115 gel bands were identified from which 87% were polymorphic. A high level of polymorphic loci (81,74 % e 68,48 %) and a high Shannon index for intra populational genetic diversity was observed for each species (Sh=0.376 e 0.289) I. cangae I. serracarajensis, respectively. The largest genetic diversity of both species relies in their own populations. The coefficient of genetic differentiation between population areas (GST) was higher in I. serracarajensis (0.5440) than in I. cangae (0.2250). Gene flow was high between I. cangae populations (1.7142) and very low in I. serracarajensis (0.4190). Principal Component Analysis (PCoA) showed that individual plants were allocated into species-specific and population groups. Overall, the results further show that I. serracarajensis (0.5440) and I. cangae are two species with considerable genetic variation. These results should be considered for effective conservation strategies of both species.