Alexandrium

Hernández-Becerril, David U., Pichardo-Velarde, Jorge G., Alonso-Rodríguez, Rosalba, Maciel-Baltazar, Ebodio, Morquecho, Lourdes, Esqueda-Lara, Karina, Barón-Campis, Sofía A. & Quiroz-González, Nataly, 2023, Diversity and distribution of species of the planktonic dinoflagellate genus Alexandrium (Dinophyta) from the tropical and subtropical Mexican Pacific Ocean, Botanica Marina (Warsaw, Poland) 66 (6), pp. 539-557 : 549

3.2 Molecular phylogeny of Mexican Pacific Alexandrium species

Only sequences obtained from strains housed in CODIMAR were considered for the phylogenetic analysis: A. affine (AAMV-1, 2, 3, 4, from BahÍa Mazatlán), A. margalefii (AMCQ-1 from BahÍa Concepción), A. tamiyavanichii (AYPV-1, from BahÍa de La Paz) and A. tropicale (ATUV-1, from Jalisco) ( Figure 1 , Table 2). Seven sequences were obtained for the D1-D2 LSU rDNA, and six sequences for the ITS rDNA (Table 2). Both topologies of the trees following the Maximum likelihood and Bayesian inference were generally consistent, thus, only the maximum likelihood trees are shown

( Figures 70 and 71 ).

The trees showed that A. affine , A. margalefii , A. tropicale and A. tamiyavanichii strains from the Mexican tropical Pacific clustered together with the corresponding species reported from various marine regions worldwide, retrieved from the NCBI, with high and moderate values of bootstrap and Bayesian posterior probabilities for LSU ( Figure 70 ) and for A. affine , A. margalefii and A. tropicale for ITS ( Figure 71 ). In the LSU rDNA tree, A. tamiyavanichii clustered close to the presumably closely related species A. cohorticula ( Figure 70 ), whereas the ITS tree showed A. tropicale close to A. fraterculus , but with moderate support values ( Figure 71 ).

The Jukes-Cantor genetic distance matrix calculated based on LSU and ITS rDNA showed the values of intraspecific distance of A. affine , A. margalefii , A. tamiyavanichii and A. tropicale compared with strains of these species from other regions of the world, and with other species of

BAMAZ, Bahía de Mazatlán, Sinaloa; BACO, Bahía Concepción, Baja California Sur; BAPAZ, Bahía de La Paz, Baja California Sur; BACUA, Bahía de

Cuastecomates, Jalisco; –, no information.

Figures

Figure 1: Map with the sampling points where species of Alexandrium were found and the sites from which the established strains were isolated.

Figure 70: Maximum-likelihood (ML) tree inferred from D1-D2 LSU rDNA sequences of Alexandrium. ML bootstrap and Bayesian posterior probabilities values are shown at branches.Bold letters indicate newly generated sequences in this study.Bootstrap values <50 and posterior probabilities <0.50 are not shown.

Figure 71: Maximum-likelihood (ML) tree inferred from ITS sequences of Alexandrium. ML bootstrap and Bayesian posterior probabilities values are shown at branches. Bold letters indicate newly generated sequences in this study. Bootstrap values <50 and posterior probabilities <0.50 are not shown.