Comparative phylogeography of two Agarophyton species in the New Zealand archipelago

Abstract

Molecular studies have reported the coexistence of two species of Agarophyton in New Zealand: the newly described A.transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more widespread A.chilense. Here, we compared the distribution, genetic diversity, and structure of both Agarophyton species throughout the archipelago using sequences of the nuclear Internal Transcribed Spacer 2 (ITS2) marker. Agarophyton chilense’s distribution was continuous and extensive along the North and South Islands, Stewart Island, and Chatham Island, and the genetic clusters were mostly concordant with boundaries between biogeographic regions. In contrast, specimens of A.transtasmanicum were collected in four sites broadly distributed in both the North and South Islands, with no clear spatial structure of the genetic diversity. Populations, where the species co‐occurred, tended to display similar levels in genetic diversity for the two species. Demographic inferences supported a postglacial demographic expansion for two A.chilense genetic clusters, one present in the South Island and the eastern coast of the North Island, and the other present in northern South Island. A third genetic cluster located on the western coast of the North Island had a signature of long‐term demographic stability. For A.transtasmanicum, the skyline plot also suggested a postglacial demographic expansion. Last, we developed a new molecular tool to quickly and easily distinguish between the two Agarophyton species, which could be used to ease future fine‐scale population studies, especially in areas where the two species coexist.

Pre‐domestication bottlenecks of the cultivated seaweed Gracilaria chilensis

“…Samples were collected across the entire distributional range of Gracilaria chilensis in the Pacific Ocean (Guillemin et al, 2008(Guillemin et al, , 2014Robitzch et al, 2019;Huanel et al, 2020), including North and South Islands of New Zealand, Chatham Island, and the south of Peru and Chile (Figure 1, Table 1; Table S1). Samples were collected from both rocky shores (i.e., attached individuals resulting from spore settlement, and therefore from sexual reproduction) and soft bottoms (i.e., free-floating thalli propagating vegetatively) when available (Table S1).…”

“…Yet, the observation of private alleles in Chilean populations of G. chilensis suggests that population expansion after colonization may have restored some level of genetic diversity (Guillemin et al, 2014). However, the poor polymorphism of the markers used so far (ITS in Guillemin et al, 2014 andHuanel et al, 2020;microsatellites in Guillemin et al, 2008) did not allow precise and statistically powerful assessment of the historical demography of G. chilensis.…”

Development of tools to rapidly identify cryptic species and characterize their genetic diversity in different European kelp species

“…Finally, we have presented species specific primers based on the mitochondrial COI gene in order to discriminate L. digitata, L. hyperborea, L. ochroleuca and H. nigripes based on the rapid species identification method developed in Brachionus (Seudre et al 2019) and Agarophyton (Huanel et al 2020). The multiplex PCR amplification of the specific primers produced fragments of different sizes for each species and the specific primers were tested in a small panel of other co-occurring and potentially confounding kelp species (Saccharina latissima 1902), confirming the sensitivity of the approach and they never produced band patterns similar to L. digitata, L. hyperborea, and H.nigripes.…”

Characterization of an Agarophyton chilense Oleoresin Containing PPARγ Natural Ligands with Insulin-Sensitizing Effects in a C57Bl/6J Mouse Model of Diet-Induced Obesity and Antioxidant Activity in Caenorhabditis elegans

“…The edible Chilean red macroalgae Agarophyton chilense (formerly Gracilaria chilensis) [1], commonly known as "pelillo", has been used as a food and medicinal herb since pre-Hispanic times in Chile, as indicated by findings at the archaeological site of Monte Verde (~14,000 years ago) [2]. Agarophyton chilense (A. chilense) is distributed in New Zealand (including Chatham Island) and South America [3][4][5][6], and although this species has good nutritional potential, it is mainly exploited for the extraction of agar-agar, a hydrocolloid [7,8].…”