Understanding biological conservation strategies: a molecular-genetic approach to the case of myrtle (Myrtus communis L.) in two Italian regions: Sardinia and Calabria

Abstract

Myrtle (Myrtus communis L.), a shrub widespread in the Mediterranean area, is the only species belonging to the Myrtaceae family growing in Europe. The pharmacological and aromatic properties of myrtle have caused a growing interest in this plant. The use of myrtle as an aromatic plant is traditionally established in the Italian regions of Sardinia and Calabria, where it is subjected to an ecological stress due to the large biomass removal for liquor production and environmental damage. The reduction in size and number of wild populations is often related to a loss of genetic variation and reproductive potential. In this study fluorescent amplified fragment length polymorphisms (fAFLPs) were employed to assess the genetic variation within and among natural populations of myrtle from Sardinia and Calabria to gain new insights into their fitness and survival potential. AMOVA analysis indicated that genetic variation was greater within populations (51.86%) than among populations (16.99%), as previously reported for outcrossing species. A significant amount of variation (31.15%) was attributed to variation between Sardinia and Calabria population groups, suggesting a genotypic differentiation between the myrtle populations of these two regions. Intra-population genetic variation, assessed by estimating expected unbiased heterozygosity (H E ), ranged from 0.0595 to 0.2595. These values resulted correlated with population extension (r = 0.918; P < 0.01) and with two reproductive parameters: seed germinability (r = 0.793; P < 0.01) and number of seeds per fruit (r = 0.631; P < 0.05). A moderate gene flow among Sardinia myrtle populations and Calabria populations (1.2719 and 1.0478, respectively) counteracts the low level of genetic variation observed in some populations and avoids their differentiation and isolation.

Variabilidade genética em populações de pitangueira oriundas de autopolinização e polinização livre, acessada por AFLP

“…Essa característica pode ser uma estratégia para atrair polinizadores (O´Brien & Calder, 1993) e, em espécies autocompatíveis que necessitam da ação de polinizadores para maior frutifi cação, a fl oração em massa pode ser uma estratégia para promover a autofertilização (Beardsell et al, 1993), pois, além de atrair polinizadores, faz com que eles permaneçam mais tempo forrageando na mesma planta. A possibilidade de aumento de endogamia por autopolinização é levantada em outras espécies da família Myrtaceae, como em Myrtus communis, uma espécie típica da fl ora Mediterrânea (Agrimonti et al, 2007), e em Syzygium nervosum, espécie de polinização cruzada endêmica da Austrá-lia (Shapcott, 1999).…”

Progress in Myrtaceae genetics and genomics: Eucalyptus as the pivotal genus

“…Genetic diversity was low while genetic differentiation was high in the endangered Metrosideros boninensis of West Pacific Islands (Kaneko et al 2008), thus indicating that, to conserve its genetic diversity, many populations need to be conserved. The level of genetic variation in Italian populations of Myrtus communis was highly correlated with the size of the population (r00.92), which appears to be caused by overharvesting of native populations for liquor production (Agrimonti et al 2007). However, in many species, there is only a weak or no correlation between genetic diversity and population size, e.g., in Myrciaria floribunda, a common tree species in the Amazonian Atlantic Forest (Franceschinelli et al 2007) or in Luma apiculata a tree species in north-western Patagonia (Caldiz and Premoli 2005), probably because the cause of the decrease in population size is relatively recent.…”

Morphological, chemical, and genetic diversity of wild myrtle(Myrtus communis L.) populations in Sicily

“…Ancient Mediterranean populations largely used myrtle for its ornamental and aromatic value (Agrimonti et al, 2007). Today the species is probably better known for its medicinal proprieties and uses in food industries (Gastaldo, 1987;Flamini et al, 2004;Barboni et al, 2010).…”