Spartina versicolor Fabre: Another case of Spartina trans-Atlantic introduction?

Abstract

International audienceIntercontinental introductions are widespread in the genus Spartina, with important ecological and evolutionary consequences. The native or introduced status of Spartina species is then critical with regard to biodiversity assessment, especially for vulnerable Mediterranean coastline ecosystems. Spartina versicolor was first recorded in southern France in 1849, then successively in various places on the European and North-African Mediterranean and Atlantic coasts. This species is considered to be either a European native or an invasive species introduced from North America which has a high morphological similarity to the Atlantic American species Spartina patens. We performed extensive sampling of S. versicolor in Europe and North Africa (from natural populations and herbarium collections) and compared these samples to other European and American Spartina species (including S. patens). Chromosome counts were reported for the first time and revealed that S. versicolor is tetraploid (2n = 4x = 40). Phylogenetic analyses based on chloroplast and nuclear ribosomal DNA sequences did not reveal any molecular variation within S. versicolor. In this species, a single haplotype, that is identical to one haplotype of S. patens, was found in the four chloroplast and the nuclear ribosomal ITS regions investigated. In addition, simple sequence repeat markers were used and revealed a low level of genetic diversity within S. versicolor, suggesting that the introduction of S. versicolor occurred from a narrow genetic pool of S. patens from North Ameri

Low genetic diversity contrasts with high phenotypic variability in heptaploid Spartina densiflora populations invading the Pacific coast of North America

“…() who recorded low genetic diversity among S. densiflora plants in San Francisco Bay and Humboldt Bay, which is consistent with the origin of San Francisco Bay population as transplants introduced from Humboldt Bay (Faber, ). Low genetic diversity is also encountered in S. versicolor populations from Europe which appear to be introduced plants from the Native American range of S. patens (Baumel et al., ). Our value of genetic differentiation among populations (Φ PT = 0.159) is in the range of those reported previously for other invasive species such as S. alterniflora in China ( F ST = 0.234, Guo et al., ; F ST = 0.100, Bernik, Li, & Blum, ), the polyploid red algae Asparagopsis taxiformis (Delile) Trevis.…”

“…The protocol used for microsatellite locus amplification by Baumel et al. () was modified as follows: Amplifications were performed in 15 μl that contained 0.4 ng/μl DNA, 1× GoTaq Flexi Buffer (Promega), 0.02 U/μl GoTaq (Flexi, Promega), 0.2 mmol/L dNTPs, 2 mmol/L MgCl 2 , and 0.04 μmol/L reverse and forward primers. FAM‐labeled reverse primers were used.…”

“…The 50 S. densiflora DNA samples previously extracted were diluted to a concentration of 10 ng/μl and amplified using the eight microsatellite primer pairs selected. The protocol used for microsatellite locus amplification by Baumel et al (2016) was modified as follows: Amplifications were performed in 15 μl that contained 0.4 ng/ μl DNA, 1× GoTaq Flexi Buffer (Promega), 0.02 U/μl GoTaq (Flexi, Promega), 0.2 mmol/L dNTPs, 2 mmol/L MgCl 2 , and 0.04 μmol/L reverse and forward primers. FAM-labeled reverse primers were used.…”

Genetic structure of Spartina hybrids between native Spartina maritima and invasive Spartina densiflora in Southwest Europe

“…densiflora (Castillo et al, 2018). The protocol used for microsatellite locus amplification followed that of Baumel et al, (2016) and Castillo et al, (2018). DNA extracts were diluted to a concentration of 10 ng µL -1 and amplified using the 8 microsatellite primer pairs selected.…”

Taxonomical and chorological notes 4 (38–58)

“…21998 It is a N American and/or W Mediterranean species, considered to be a native or invasive species in Europe. According to the recent results, European populations are likely to be derived from an introduction of S. patens (Baumel et al 2016). It is widespread in W Europe, and has recently been found also in the eastern part of Greece (Dimopoulos et al 2013).…”