Phylogenetic Relationship Of Audouinella Based On Gene Sequences

Since the establishment of the genus Audouinella Bory in1823, the definition had been proposed by different scholars, and classification standard also differ. Now, the characteristics of Audouinella are such:Thallus is branch wire body made up of single cells, each cell have a few circumambient, discoid chromatophore, sometimes edge shallowly crack, no protein nuclear. It can produce single sporangium for asexual reproductive and has sexual reproduction. All the report were freshwater. The alge is belong to Rhodophyta, Rhodophyceae, Florideophycidae, Acrochaetiales, Acrochaetiaceae. Now on, the report about genus Audouinella Bory in China is10species and2change species, but have no sexual reproduction report.The life-history of Audouinella consists of three kinds of thallus: isomorphic gametophyte, tetrasporaphite, the filament in which asexual reproduction relies on monospore. In general, the genus mainly is asexual reproductive, so we rarely found the specimen with carpogonium, spermatangium or tetrasporangium. The two other orders of red alga, Batrachospemale and Thoreales, the life history of which also contain three kinds of thallus, gametophyte, carposporophyte and the filament in which asexual reproduction relies on monospore. What’s more, the filament of the two orders appear to be very similar with Audouinella, morphological identification is very difficult.This study observed the morphological structure of two kinds of Audouinella plant, A.heterospora and A.sinensis collected from Shanxi province in China, constructed the system evolutionary tree of BA (Bayesian analysis), ML (maximum likelihood), NJ (maximum parsimony) based on sequences of three genes.The research of morphological structure found that Audouinella heterospora and Audouinella sinensis are all the filament in which asexual reproduction relies on monospore, have no sexual reproduction. The outline and microstructure were all accord with the characteristic of morphology. molecular classification system research showed that both two Audouinella plant don’t get together with the genus Audouinella Bory, yet genetic relationship of which is very close to Thoreales and the support rate are very high, in especial rbcL、SSU COI Therefore, based on the molecular and morphological research, the "Audouinella" plant can belong to Thoreales, not Audouinella Bory. The material collecting zone also exist Thoreales plants, so the two Audouinella plant can be the vegetative body period of Thoreales plants.