A novel species in the genusHeveochlorella(Trebouxiophyceae, Chlorophyta) witnesses the evolution from an epiphytic into an endophytic lifestyle in tree-dwelling green algae

Abstract

(2013) A novel species in the genus Heveochlorella (Trebouxiophyceae, Chlorophyta) witnesses the evolution from an epiphytic into an endophytic lifestyle in tree-dwelling green algae, European Journal of Phycology, 48:2, 200-209, DOI: 10.1080/09670262.2013 Roystonea regia is a popular landscape palm famous for its smoothly sculpted white trunk, but sometimes it is spoiled by epiphytic green algae inhabiting the bark. We identified a trebouxiophycean green alga as the single dominant species growing on the trunk of a royal palm in Hainan, China. Light and transmission electron microscopy showed adult cells to be spherical with a diameter of 6.4-13.7 μm, and to contain a single cup-shaped parietal chloroplast. Each chloroplast contained a pyrenoid of 1.4-2.1 μm in diameter. The pyrenoid was penetrated by radially arranged tubular invaginations surrounded by pyrenoglobuli, which is similar to Heveochlorella hainangensis. Phylogenetic analyses inferred from nuclear-encoded 18S rRNA sequences placed strain ITBB A3-8 in the Watanabea clade (Trebouxiophyceae, Chlorophyta), closely related to H. hainangensis. But strain ITBB A3-8 differs sufficiently from H. hainangensis in significant aspects of ultrastructure, physiology, and nuclear and plastid ribosomal RNA and ITS sequences to be treated as a novel species, H. roystonensis Shuai Ma, V. Huss, Xuepiao Sun & Jiaming Zhang, sp. nov. The growth of the epiphytic H. roystonensis seems to be promoted by air pollution in the city, while the endophytic H. hainangensis requires an organic carbon source for optimal growth. Thus in the genus Heveochlorella both an epiphytic and an endophytic lifestyle of tree-dwelling green algae can be observed.

Community structure of corticolous microalgae within a single forest stand: evaluating the effects of bark surface pH and tree species

“…Traditional taxonomy of these organisms, based on their cellular morphology, generally underestimates their true phylogenetic diversity (riNdi et al 2009;friedl & ryBalKa 2012). Consequently, a number of new coccoid taxa were recently described using molecular methods (Němcová et al 2011;ma et al 2013;. However, despite the low morphological diversity of corticolous microalgae, their ecology and community structure can still be successfully studied using a combination of cultivation techniques and detailed light microscopy.…”

Molecular diversity of green corticolous microalgae from two sub-Mediterranean European localities

“…A number of new taxa of chlorelloid green microalgae, isolated from various corticolous biofilms, were recently described taxonomically and defined by molecular phylogenetic methods (e.g. Darienko et al, 2010;Ma et al, 2013;Neustupa et al, 2013a, b). Notably, the species and genera belonging to the phylogenetically defined Watanabea clade of Trebouxiophyceae seem to be especially abundant in various subaerial microhabitats.…”

“…The sister genus Parachloroidium includes two recently described species that are only known from corticolous biofilms (Neustupa et al, 2013b). In addition, the genera Kalinella and Heveochlorella were described from tropical South-East Asian corticolous assemblages (Zhang et al, 2008;Neustupa et al, 2009;Ma et al, 2013). Kalinella apyrenoidosa, one of the two species of the genus Kalinella, was recently described from a sub-Mediterranean corticolous sample (Neustupa et al, 2013a).…”

Phyllosiphon ari sp. nov. (Watanabea clade, Trebouxiophyceae), a new parasitic species isolated from leaves of Arum italicum (Araceae)<br />

“…Three of four species of the genus Chloroidium have beeen frequently found in subaerial biofilms, while a single species occurs in freshwater habitats (Darienko et al 2010). The genera Kalinella and Heveochlorella were described from corticolous biofilms in tropical South-East Asia (Zhang et al 2008, Neustupa et al 2009, Ma et al 2013. The genus Parachloroidium was recently described from corticolous samples in sub-Mediterranean habitats (Neustupa et al 2013b).…”