Abstract
Congracilaria babae was first reported as a red alga parasitic on the thallus of Gracilaria salicornia based on Japanese materials. It was circumscribed to have deep spermatangial cavities, coloration similar to its host and the absence of rhizoids. We observed a parasitic red alga with morphological and anatomical features suggestive of C. babae on a Hydropuntia species collected from Sabah, East Malaysia. We addressed the taxonomic affinities of the parasite growing on Hydropuntia sp. based on the DNA sequence of molecular markers from the nuclear, mitochondrial and plastid genomes (nuclear ITS region, mitochondrial cox1 gene and plastid rbcL gene). Phylogenetic analyses based on all genetic markers also implied the monophyly of the parasite from Hydropuntia sp. and C. babae, suggesting their conspecificity. The parasite from Hydropuntia sp. has a DNA signature characteristic to C. babae in having plastid rbcL gene sequence identical to G. salicornia. C. babae is likely to have evolved directly from G. salicornia and subsequently radiated onto a secondary host Hydropuntia sp. We also recommend the transfer of C. babae to the genus Gracilaria and propose a new combination, G. babae, based on the anatomical observations and molecular data.
Highlights
Red algal parasites have been described from at least eight orders, including Ceramiales, Corallinales, Gigartinales, Gracilariales, Halymeniales, Palmariales, Plocamiales and Rhodymeniales [1,2]
In an algal collection from Sabah, East Malaysia, we found a red algal parasite suggestive of Congracilaria babae Yamamoto on the host Hydropuntia species attached to the monolines of Kappaphycus in aquaculture farms
Habit: The species was parasitic on a Hydropuntia sp. found attached on the monolines of Kappaphycus around Kampung Lok Butun in Pulau Bum Bum, Sabah, Malaysia
Summary
Red algal parasites have been described from at least eight orders, including Ceramiales, Corallinales, Gigartinales, Gracilariales, Halymeniales, Palmariales, Plocamiales and Rhodymeniales [1,2]. The term ‘red algal parasites’, in this context, strictly refers to the parasites that evolved from the free-living red algae lineage [3]. They are generally small and morphologically simple, composed of branching filaments of cells which penetrate between the cells of the pseudoparenchymatous host and a tissue mass that protrudes from the host thallus and bears reproductive structures [4]. A previous study [5] showed that the occurrence of red algal parasite reduced the growth rate of their hosts resulting in lower yield of the hosts This may have a negative impact on the economic potential of the seaweed mariculture system, there is no substantial evidence to show that the production and properties of phycocolloids extracted from the infected seaweeds are compromised [5]. An understanding in the systematics and taxonomy of a red algal parasite with reference to its host species would immensely help in identifying a potential model organism for functional studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
