Gracilarioid algae (Rhodophyta): strains selections, reproductive aspects and gene expression

Abstract

This project is linked to a line of research initiated in our laboratory, as well as at the national level, related to the knowledge of the intraspecific diversity of seaweed, including approaches about reproduction, physiology and genetics. Two species of gracilarioid algae (Gracilariales, Rhodophyta), widely distributed on the Brazilian coast, are included in this project: Gracilaria caudata and Gracilariopsis tenuifrons. We proposed, for Gracilaria caudata: i, to select strains with greater vegetative vigor for future applications, such as integrated crops and mariculture tests; ii, to continue the investigations on aspects of life history, related to the germination of tetraspores on tetrasporophytes in a variant of green color and wild strain investigating the putative inheritance of this character; and iii, comparatively evaluate physiological aspects, such as growth rates, parameters of photosynthesis and pigment composition, of free-living gametophytes and epiphytes in parental tetrasporophytes, taking into account the color (red or green). For Gracilariopsis tenuifrons, we intend to evaluate genetic responses to thermal stress by transcriptome analysis. The overall analysis of these investigations should expand knowledge about the intraspecific diversity of the selected species. It should also allow interpretations about the adaptive advantages of the occurrence of epiphytism in tetrasporophytes and allow the selection of strains that may be used in practical applications. (AU)