One thousand plant transcriptomes and the phylogenomics of green plants

Abstract: Green plants (Viridiplantae) include around 450,000–500,000 species1, 2 of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life

Novitates neocaledonicae VI : Acropogon mesophilus (Malvaceae, Sterculioideae), a rare and threatened new species from the mesic forest of New Caledonia

A new species, Acropogon mesophilus Munzinger & Gateble (Malvaceae, Sterculioideae), is described from New Caledonia. This species is endemic to non-ultramafic areas, along the southwestern coast of Grande-Terre. The species has large leaves, widely ovate to ovate, and entire, and might be confused with only two other endemic species, namely A. bullatus (Pancher & Sebert) Morat and A. veillonii Morat. However, A. mesophilus differs from the other two species most evidently by its leaves 3-nerved, flat, and with truncate to rounded bases, versus leaves 5-nerved, bullate, and with cordate bases. A line drawing and color photos are provided for the new species, along with a discussion of its morphological affinities and a preliminary risk of extinction assessment of Endangered

One new endemic plant species on average per month in New Caledonia, including eight more new species from ile Art (Belep Islands), a major micro-hotspot in need of protection

The New Caledonian biodiversity hotspot contains many micro-hotspots that exhibit high plant micro-endemism, and that are facing different types and intensities of threats. The Belep archipelago, and especially ile Art, with 24 and 21 respective narrowly endemic species (1 Extinct, 21 Critically Endangered and 2 Endangered), should be considered as the most sensitive micro-hotspot of plant diversity in New Caledonia because of the high anthropogenic threat of fire. Nano-hotspots could also be defined for the low forest remnants of the southern and northern plateaus of ile Art. With an average rate of more than one new species described for New Caledonia each month since January 2000 and five new endemics for the Belep archipelago since 2009, the state of knowledge of the flora is steadily improving. The present account of eight new species from ile Art (Bocquillonia montrouzieri Gateble & McPherson, Cleidion artense Gateble & McPherson, Endiandra artensis Munzinger & McPherson, Eugenia belepiana J.W.Dawson ex N.Snow, Eugenia insulartensis J.W.Dawson ex N.Snow, Macaranga latebrosa Gateble & McPherson, Planchonella serpentinicola Swenson & Munzinger and Psychotria neodouarrei Barrabe & A.Martini) further demonstrates the need both to recognise the Belep Islands as a major New Caledonian micro-hotspot and to formulate concrete conservation programs for the archipelago

Structure and genetic diversity of Ixora margaretae an endangered species. A baseline study for conservation and restoration of natural dry forest of New Caledonia

International audienceThe dry forests of New Caledonia are an excep- tional ecosystem because of their numerous endemic botan- ical species and their highly diversified fauna of insects, mollusks, reptiles and birds. Unfortunately, the area of the dry forests has been significantly reduced, mainly by human activities. Ecological, phenological and genetic analysis of Ixora margaretae, a symbolic species of the sclerophyll forest, has revealed contrasting traits among natural stands. The division of the natural range and then the separation of forest islands has greatly reduced the existing genetic vari- ability of this species. The genetic diversity is strongly structured in genetic clusters which correspond well to spe- cific ecotypes according to the environmental conditions and the forest types. Furthermore, genetic analysis of the reproductive and non-reproductive trees as well the half- sib families obtained by complete protection of mothertrees has revealed substantial genetic drift which has resulted in increased loss of allelic variability. The total consumption of seeds by mainly rats confirms the ob- served absence of natural regeneration. All these results show that measures taken to protect the stands of dry forests will not be enough to maintain sufficient genetic variability of I. margaretae populations in the long term. Assisted regeneration with control of the increase in var- iability will be necessary to maintain the biodiversity of the species. The results obtained for I. margaretae must be confirmed with other symbolic species in order to take the necessary measures for the effective preservation of the dry forests in New Caledoni

State of the World’s Plants and Fungi 2020. Royal Botanic Gardens, Kew

Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity