Molecular identification of fungal isolates and hatching success of green turtle (Chelonia mydas) nests

Abstract

The aim of this study is to investigate the fungal diversity of green turtle nests and to examine phylogenetic relationships among these isolates. During the nesting season, samples of intra-nest sand and failed eggs were collected from 25% of the surviving nests in Sugözü Beaches, which are amongst the most important nesting beaches for endangered green turtles in the Mediterranean. Twenty-three fungi were identified by molecular techniques. Fungal isolates belonged to genera Aspergillus, Emericella, Rhizopus, Actinomucor and Apophysomyces with two undescribed species. Aspergillus variecolor, Aspergillus quadrilinieatus, Aspergillus tubingensis, Rhizopus oryzae, Actinomucor elegans and Apophysomyces variabilis were firstly detected in all sea turtle nests within this study. Our results demonstrate that 36.4% of the nests had fungal contamination. Also hatching success of the nests contaminated by fungi were significantly lower than the uncontaminated nests (P = 0.029). Also, this may represent a threat to marine turtles and a risk for the health of conservation workers. This study is the first molecular phylogenetic study associated with sea turtle nests in the eastern Mediterranean coast and contributes to the wider body of literature on fungal invasion of sea turtle nests with firstly isolated species. These findings are important for improving potential conservation measures for the nest sites.

First data on microflora of loggerhead sea turtle (Caretta caretta) nests from the coastlines of Sicily (Italy)

“…Additionally, Bailey et al (2018) demonstrated the presence of Fusarium DNA (F. falciforme and F. keratoplasticum) in embryonic fluid and biofilms from 73 fully incubated, unhatched loggerhead sea turtle eggs collected from different regions of North America. However, a recent molecular study from Turkey identified fungi from five genera (Aspergillus, Emericella, Rhizopus, Actinomucor and Apophysomyces) isolated from successfully hatched green turtle (Chelonia mydas) nests on eastern Mediterranean coasts (Candan, 2018). Moreover, these authors demonstrated that the hatching success of nests contaminated by fungi was significantly lower than those of uncontaminated nests.…”

“…In terms of Gram-positive bacteria, the most frequently isolated species of staphylococci from C. mydas nests in Costa Rica were Staphylococcus aureus, Staphylococcus intermedius, Staphylococcus epidermidis and Staphylococcus cromogenes (Santoro et al, 2006). Those fungal species isolated from sea turtle nests and eggs come from Aspergillus, Fusarium, Chrysosporium, Penicillium, Emericella, Rhizopus, Actinomucor and Apophysomyces genera (Bailey et al, 2018;Candan, 2018;Güçlü et al, 2010;Phillott et al, 2002). These genera are predominantly saprophytic species that become opportunistic pathogens under particular conditions, e.g.…”

Newly emerging diseases of marine turtles, especially sea turtle egg fusariosis (SEFT), caused by species in the Fusarium solani complex (FSSC)

“…Species in the FSSC are not the only fungi found to penetrate sea turtle egg shells. For example, Candan ( 2018 ) also identified several species of Aspergillus, Emericella, Rhizopus, Actinomucor , and Apohysomyces in the nests of living green turtles using molecular methods. There are reports of fungal pathogens of sea turtles in many parts of the world, including Australia, North America, South America, Asia, Europe and Africa ( Table 1 ).…”

The Investigations of the Nesting Status of the Green Turtle Chelonia Mydas on Yeniyurt Beach (Hatay) in the Northeastern Mediterranean, Turkey

“…This value was found higher on other green turtle nesting beaches such as Akyatan 76% [19], Kazanlı 82.9% [20], Samandağ 69.9% [25], Northern Cyprus 84.2% [26]. Hatching success can be influenced by fungal infections [27], moisture [28] and clutch size [29]. However, [30] concluded that environmental factors they examined were not correlated with hatching success.…”