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The species Syagrus romanzoffiana, a native palm tree of South America, is widely distributed and well adapted to southern Brazil. It is an important economic, cultural, and ecological resource, being the preferred food of diverse animal species, involving complex ecological relationships. However, despite numerous molecular studies on native plants, specific molecular markers, such as expressed sequence tagsimple sequence repeats (EST-SSRs), are lacking, and there are few SSR markers for this species. Molecular data about individuals and their populations offers new perspectives for management, conservation, and economic exploitation. Here we tested 21 microsatellite loci known from three species of the family Arecaceae in three native populations of S. romanzoffiana in the state of Rio Grande do Sul, in southern Brazil. Among the 21 primer pairs tested, 12 produced an amplification product. Five loci were chosen and subjected to diversity tests. The populations presented between three and nine alleles per locus, and acceptable genetic diversity values; the expected heterozygosity ranged from 0.460 to 0.864, while the observed heterozygosity ranged from 0.100 to 1.000. We conclude that various microsatellite markers developed for other species of the family Arecaceae are suitable for molecular analysis of S. romanzoffiana populations.

The species Syagrus romanzoffiana is a monocot belonging to the family Arecaceae; it is a palm endemic to South America and is widely distributed throughout the southeast and south of Brazil, including the State of Rio Grande do Sul. To estimate the genetic diversity and structure of the species in the watersheds of Rio Grande do Sul, five simple sequence repeat markers were used to analyze 90 individuals, representing three populations. The genetic structure of S. romanzoffiana groups was evaluated through the analysis of molecular variance and a multivariate analysis based on Nei's genetic distance. The evaluated populations showed significant intrapopulation molecular variation (F ST ¼ 0.11). The observed heterozygosity (H O ¼ 0.17) was lower than the expected heterozygosity (H E ¼ 0.75). These data indicate that although the number of individuals is high, the diversity is low for some indices. Our findings suggest that further studies are needed, particularly on the genetics of natural populations of S. romanzoffiana in Rio Grande do Sul State, to fully characterize their genetic diversity and structure and determine strategies and priority areas for species conservation.

Abstract:In this study, the organelle genomes of Polytrichum juniperinum Hedw. and Polytrichum strictum Menzies ex Brid. (Polytrichaceae, Bryophyta) from Antarctica were sequenced and compared with the plastomes of the model moss species Physcomitrella patens Brid. The sizes of the cpDNA in P. juniperinum and P. strictum were estimated to be 55,168 and 20,183 bp, respectively; the sizes of the mtDNA were 88,021 and 58,896 bp, respectively. The genomes are very similar to each other, with the possible loss of petN in the cpDNA, which also showed some gene inversions when compared with the cpDNAs of P. patens Brid. In the mtDNA, it is possible that rps10 was lost. In contrast, Antarctic Polytrichaceae species have nad7 and orf187, without the occurrence of rearrangement events. Phylogenomic analyses of the plastid and mitochondria revealed that the majority-rule tree suggests some differences in the plastids ancestry, however, P. juniperinum and P. strictum were grouped in the same clade in chloroplast, but in mitochondria P. strictum was grouped with Atrichum angustatum (Brid.) Bruch & Schimp. This study helped us understand the evolution of plastomes and chondriosomes in the family Polytrichaceae, and suggest a hybridization event with relation to the mitochondrial data.

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