Patterns of Endemism in Lichens: Another Paradigm-Shifting Example in the Lichen Genus Xanthoparmelia from Macaronesia.

It has long been assumed that lichen-forming fungi have very large distribution ranges, and that endemic species are rare in this group of organisms. This is likely a consequence of the "everything small is everywhere" paradigm that has been traditionally applied to cryptogams. However, the description of numerous endemic species over the last decades, many of them in oceanic islands, is challenging this view. In this study, we provide another example, Xanthoparmelia ramosae, a species that is described here as new to science on the basis of morphological, chemical, and macroclimatic data, and three molecular markers (ITS rDNA, nuLSU rDNA, and mtSSU). The new species is endemic to the island of Gran Canaria but clusters into a clade composed exclusively of specimens collected in Eastern Africa, a disjunction that is here reported for the first time in lichen-forming fungi. Through the use of dating analysis, we have found that Xanthoparmelia ramosae diverged from its closely related African taxa in the Pliocene. This result, together with the reproductive strategy of the species, points to the Relict theory as a likely mechanism behind the disjunction, although the large gap in lichenological knowledge in Africa makes this possibility hard to explore any further.

Biostimulant activity of Galaxaura rugosa seaweed extracts against water deficit stress in tomato seedlings involves activation of ABA signaling.

Water scarcity is a serious constraint for agriculture, and global warming and climate change can exacerbate it in many areas. Therefore, sustainable approaches must be implemented to deal with current and future water scarcity scenarios. Genetic and chemical approaches are being applied to manage this limitation and maintain crop yields. In particular, biostimulants obtained from natural sources such as marine algae are promising aids for coping with water deficit stress in agriculture. Here we present a bioprospection study of extracts of the macroalgae Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis, Ulva clathrata, Cystoseira foeniculacea, Cystoseira humilis, Lobophora dagamae, Colpomenia sinuosa and Halopteris scoparia from the north coast of Tenerife, in the Canary Islands. The aqueous extracts of Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis and Cystoseira humilis show biostimulant activity against water deficit stress in tomato seedlings under controlled conditions, providing higher tolerance than the mock-treated control. The Galaxaura rugosa extract showed the highest biostimulant activity against water deficit stress. We demonstrate that this positive effect involves the activation of the abscisic acid (ABA) pathway in Arabidopsis thaliana (arabidopsis) and Solanum lycopersicum (tomato). Application of G. rugosa extract to the root system by drenching tomato seedlings subjected to water deficit leads to improved CO2 assimilation and water use efficiency (WUEp), compared to mock-treated plants. These results highlight a new potential seaweed source of substances with osmoprotectant properties, useful for biostimulant development. Future studies may provide further insight into which components of the seaweed extract induce activation of the ABA pathway.

A New Species from the Canary Islands Increases the Diversity of the Red Algal Genus Pterocladiella in the Northeastern Atlantic.

Environmental and human factors are inducing a drastic decline in many marine algae in regions with a high floristic richness as in the Canary Islands. Simultaneously, undescribed algal species continue to be discovered, suggesting a probable loss in diversity, before being properly identified and catalogued. Turf-forming Gelidiales occur in marine littoral communities from tropical to warm temperate regions and are challenging to identify correctly because of their small size and simple morphology. In the present study, we combined morphological and molecular phylogenetics methods to study a turf-forming species of the genus Pterocladiella from the Canary Islands (NE Atlantic). Both cox1 and rbcL gene analyses revealed a novel species described here, Pterocladiella canariensis sp. nov. The new species has no single unique morphological feature, but it is different by a distinctive combination of attributes, namely, minute size less than 18 mm in height, ribbon-like erect axes, small polygonal cortical cells, cystocarp circular in outline with placental tissue attached to the floor, spermatangial sori with sterile margins with spermatangia simultaneously formed on both sides of the blade, and tetrasporangia arranged in V-shaped rows. Phylogenies inferred from cox1 and concatenated genes (cox1 + rbcL) suggest a link to only two Pterocladiella species endemic to South Africa and Madagascar; nevertheless, the rbcL gene establishes P. canariensis as the earliest divergent lineage of the genus.

Environmental and human factors drive the subtropical marine forests of Gongolaria abies-marina to extinction.

Large brown macroalgae are foundational threatened species in coastal ecosystems from the subtropical northeastern Atlantic, where they have exhibited a drastic decline in recent years. This study describes the potential habitat of Gongolaria abies-marina, its current distribution and conservation status, and the major drivers of population decline. The results show a strong reduction of more than 97% of G. abies-marina populations in the last thirty years and highlight the effects of drivers vary in terms of spatial heterogeneity. A decrease in the frequency of high waves and high human footprint are the principal factors accounting for the long-term decline in G. abies-marina populations. UV radiation and sea surface temperature have an important correlation only in certain locations. Both the methodology and the large amount of data analyzed in this study provide a valuable tool for the conservation and restoration of threatened macroalgae.