Climatic niche evolution and niche conservatism of Nymphaea species in Africa, South America, and Australia.

BACKGROUND: Interest in the evolution of climatic niches, particularly in understanding the potential adaptive responses of species under climate change, has increased both theoretically and within macroecological studies. These studies have provided valuable insights into how climatic traits of species influence their niche evolution. In this study, we aim to investigate whether niche conservatism plays a role in the species diversification of Nymphaea, a group of aquatic plants with a cosmopolitan distribution that is facing severe habitat loss. We will use climatic models and phylogenetic data for 23 species to reconstruct Nymphaea's niche evolution, measure niche overlap, and assess disparity through time while testing for evolutionary models. RESULTS: There was a lot of overlap in niches both within and between groups, especially for species that can be found in many places. The breadth and peaks of the niche profile varied depending on the bioclimatic variables, which suggested that the species evolved differently to cope with changes in climate. The analysis also showed that evolutionary changes happened across the phylogeny, with weak to moderate signals. The morphological disparity index (MDI) values indicated that there were disparities within subclades over time but not between or among them. Niche reconstruction and evolution analysis revealed both convergent and divergent evolution among various variables. For example, N. immutabilis, N. atrans, N. violancea, and N. nouchali evolved towards intermediate temperatures for bio2 and bio3 (isothermity) while moving towards extreme temperatures for bio8 and bio9 (wettest and driest average quarterly temperatures). CONCLUSION: Our study will improve our understanding of how changes in climatic niches are potentially driving the evolution of Nymphaea. It has significant scientific implications for the limits, assemblages, evolution, and diversification of species. This information is crucial for the ongoing efforts of conservation and management, particularly considering the inevitable effects of climate change.

The complete chloroplast genomes of two species in threatened monocot genus Caldesia in China.

Caldesia is a genus in the family Alismataceae mainly found in the tropical and temperate regions of the Northern hemisphere. In China, two species, Caldesia parnassifolia, and Caldesia grandis are recorded as critically endangered in sporadic regions. Available protection of the genetic resource of these threatened species has been impeded due to limited genomic information. Here, we sequence the whole chloroplast (cp) genome of the two Caldesia species using high throughput sequencing technology. The whole cp genomes of C. parnassifolia and C. grandis were 167,647 bp and 168,500 bp, respectively with a typical quadripartite structure. There were 115 unique genes with 81 protein-coding genes, 31 tRNA genes, and four rRNA genes. Both species showed a GC content of 37.1%. A duplication of two tRNA genes and a ~ 6 kb inversion region in the LSC was noted in both species. Mononucleotide simple sequence repeats (SSRs) A/T were most abundant for both Caldesia species. High nucleotide variability was recorded in ycf1 gene and trnK-UUU/rps16 intergenic spacer region. All RNA editing conversions were C-U in 23 and 24 protein-coding genes for C. parnassifolia and C. grandis, respectively. Phylogenetic analysis placed both Caldesia species as sister to Sagittaria lichuanensis. This study will be useful for further evolutionary, systematic researches and conservation of the genus Caldesia.

Ecological Niche Modeling of Water Lily (Nymphaea L.) Species in Australia under Climate Change to Ascertain Habitat Suitability for Conservation Measures.

The International Panel on Climate Change (IPCC) projects a global temperature rise of 4.3 ± 0.7 °C by 2100 and an extinction of 8.5% in one out of every six species. Australia's aquatic ecosystem is no exception; habitat loss, fragmentation, and loss of biodiversity are being experienced. As the center for Nymphaea species distribution, it presents the culturally, ecologically, and scientifically important genus as the best candidate for habitat suitability assessment in climate change, whose habitat suitability is presumed to decline. The models were run according to the maximum entropy (MaxEnt) method, using one general circulation model (GCM). Projections were made for the current, past, and future in medium (4.5) and high (8.5) representative concentration pathways. Significantly, bio2 and bio15 were highly preferred among the species. Less distribution was noted in West Australia compared to the north, east, and south of the continent, while north of the continent in Western Australia, Northern Territory, and Queensland indicate more habitat contractions compared to the east and southeast of Queensland and New South Wales, although it receives high precipitation. Generally, the species respond variably to both temperature and precipitation variables which is a key species response factor for planners and decision makers in species habitat and biodiversity conservation.

The complete chloroplast genome of Protea kilimandscharica Engl. (Proteaceae).

Protea kilimandscharica is endemic to the heath zone of Mt Kenya, restricted to the rocky slopes of the mountain. The complete chloroplast genome of P. kilimandscharica was determined by next-generation sequencing technology, with a total length of 158,657 bp. The cp genome encodes 115 unique genes, with four rRNA genes, 81 protein-coding genes (PCGs), and 30 tRNA genes. A 3.1 kb inversion was noted in the LSC. Phylogenetic analysis, based on 75 common protein-coding genes revealed P. kilimandscharica as sister to Macadamia integrifolia and Macadamia ternifolia.

The complete plastome sequences of five Aponogeton species (Aponogetonaceae): Insights into the structural organization and mutational hotspots.

Members of the aquatic plant genus Aponogeton are widely used commercially in aquariums because of their variable leaf shape and unique inflorescences. However, due to extensive similarity between species in this genus, morphological characters are generally inadequate for taxonomic classification. Currently, molecular makers available for taxonomic and phylogenetic studies of Aponogeton are limited. One approach to clarifying relationships between species in these complex groups is to use divergence hotspot regions within the genome. Here, we sequenced and analyzed the plastomes of five Aponogeton species collected from China, Zambia, and Kenya, and subsequently screened these plastomes for divergent DNA hotspots. The five plastomes are circular structures with sizes ranging from 154,167 bp to 154,860 bp. The Large and the Small Single Copies are separated by two Inverted Repeats. One hundred and thirteen unique genes were identified including 79 protein-coding, 30 tRNA, and four rRNA genes. We found that the most abundant repeats in all but one species were mononucleotide repeats (A/T) and that there were 23 potential RNA ending sites. Interestingly, a ~3 kb inversion, which includes the accD gene, was detected within the Asian species of Aponogeton. The inversion may be related to more frequent exchanges between this region and the nuclear genome. Furthermore, we detected mutational hotspot sites among the five Aponogeton species. Three of these hotspots are intergenic spacer regions (accD-psaI, rbcL-accD and trnH-GUG-psbA) that might be suitable for use as barcodes to resolve intra-generic relationships. We also identified four highly variable protein-coding genes (ccsA, rpl22, rps16 and ycf1) may be used as barcodes to resolve the higher-level phylogenies. Our study will provide valuable molecular resources for the taxonomic and phylogenomic study of the complex genus Aponogeton.