Manhães et al. 2015 (Conference Paper) Pitcairnia

A combined molecular and cytogenetic approach to study Pitcairnia azouryi (Bromeliaceae)

Author(s):—V. C. Manhães, F.D. Miranda, W.R. Clarindo & T. Tavares Carrijo in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—This study reports the discovery of new areas of occurrence of Pitcairnia azouryi Martinelli & Forzza, and the studyof their populations regarding the species? genetic diversity, the amount of nuclear DNA and chromosome number.Seven new areas of occurrence for this species were located between northern Rio de Janeiro (RJ) State and southernEspírito Santo (ES) State, and georeferenced to the other studies. Leaf samples of 13?15 individuals were collectedin five of these populations (PLB - Pedra Lisa Burarama, PA - Pedra das Andorinhas, PTI - Pedra Três Irmãs, PPC -Pedra Parada Cristal and PLC - Pedra Lisa Campos), totaling 66 individuals. Nine SSR markers were used in PCRs.Genetic polymorphisms were identified from polymorphism between individuals sampled, detected by electrophoresison an 8% acrylamide gel. The parameters of diversity and genetic structure of populations were calculated using thesoftware Fstat, PopGene and Structure. The flow cytometry analysis was performed using leaf samples obtained fromadult individuals of five populations. Cytogenetic analyses were performed with roots obtained from germinated seedscollected in two populations. The nine SSR primers produced satisfactory amplification products, and proved to bepolymorphic. The number of alleles per locus ranged between two and eight. The values of gene diversity index (H?)and the fixation index (F) in populations ranged from 0.440 to 0.552 and 0.0046 to 0.1718, respectively. The Gst values observed showed that 87.33% of the total genetic variation is found within populations and the occurrence ofgene flow (Nm) 1,073 (average number of migrants per generation). Bayesian analysis indicated that a model of k =3 populations is able to better capture the variation in the data on the genetic structure. The high variation of fixationindex added to the large genetic variation within and moderate genetic differentiation among populations suggest theoccurrence of the founder effect in the dispersion of new individuals into new locations, followed by genetic drift,especially for the population at Campos dos Goytacazes. The flow cytometry analysis showed that the nuclear DNAcontent is 2C = 1.16 picograms in all populations analyzed, except on PLC population, whose DNA content (2C=
2.32 picograms) was measured twice. This result was explained by cytogenetic analysis which revealed individuals
with 2n = 50 chromosomes in ES and individuals with 2n = 100 chromosomes in RJ. This result may be due to PLC?s
geographical isolation, the environmental characteristics of the local or even evolutionary processes.

Keywords:—Atlantic Forest; Conservation Biology; Rocky Outcrops.