Science Enabled by Specimen Data

Calleja-Satrustegui, A., A. Echeverría, I. Ariz, J. Peralta de Andrés, and E. M. González. 2024. Unlocking nature’s drought resilience: a focus on the parsimonious root phenotype and specialised root metabolism in wild Medicago populations. Plant and Soil. https://doi.org/10.1007/s11104-024-06943-w

Abstract  Background and aims Crop wild relatives, exposed to strong natural selection, exhibit effective tolerance traits against stresses. While an aggressive root proliferation phenotype has long been considered advantageous for a range of stresses, it appears to be counterproductive under drought due to its high metabolic cost. Recently, a parsimonious root phenotype, metabolically more efficient, has been suggested to be better adapted to semiarid environments, although it is not clear that this phenotype is a trait exhibited by crop wild relatives. Methods Firstly, we analysed the root phenotype and carbon metabolism in four Medicago crop wild relatives adapted to a semiarid environment and compared them with the cultivated M. truncatula Jemalong (A17). Secondly, we exposed the cultivated (probably the least adapted genotype to aridity) and the wild (the most common one in arid zones) M. truncatula genotypes to water deficit. The carbon metabolism response in different parts of their roots was analysed. Results A reduced carbon investment per unit of root length was a common trait in the four wild genotypes, indicative of an evolution towards a parsimonious root phenotype. During the water deficit experiment, the wild M. truncatula showed higher tolerance to drought, along with a superior ability of its taproot to partition sucrose and enhanced capacity of its fibrous roots to maintain sugar homeostasis. Conclusion A parsimonious root phenotype and the spatial specialization of root carbon metabolism represent two important drought tolerance traits. This work provides relevant findings to understand the response of Medicago species roots to water deficit.

Saunders, T. C., I. Larridon, W. J. Baker, R. L. Barrett, F. Forest, E. Françoso, O. Maurin, et al. 2024. Tangled webs and spider‐flowers: Phylogenomics, biogeography, and seed morphology inform the evolutionary history of Cleomaceae. American Journal of Botany 111. https://doi.org/10.1002/ajb2.16399

Premise Cleomaceae is an important model clade for studies of evolutionary processes including genome evolution, floral form diversification, and photosynthetic pathway evolution. Diversification and divergence patterns in Cleomaceae remain tangled as research has been restricted by its worldwide distribution, limited genetic sampling and species coverage, and a lack of definitive fossil calibration points.MethodsWe used target sequence capture and the Angiosperms353 probe set to perform a phylogenetic study of Cleomaceae. We estimated divergence times and biogeographic analyses to explore the origin and diversification of the family. Seed morphology across extant taxa was documented with multifocal image‐stacking techniques and morphological characters were extracted, analyzed, and compared to fossil records.ResultsWe recovered a well‐supported and resolved phylogenetic tree of Cleomaceae generic relationships that includes 236 (~86%) species. We identified 11 principal clades and confidently placed Cleomella as sister to the rest of the family. Our analyses suggested that Cleomaceae and Brassicaceae diverged ~56 mya, and Cleomaceae began to diversify ~53 mya in the Palearctic and Africa. Multiple transatlantic disjunct distributions were identified. Seeds were imaged from 218 (~80%) species in the family and compared to all known fossil species.ConclusionsOur results represent the most comprehensive phylogenetic study of Cleomaceae to date. We identified transatlantic disjunctions and proposed explanations for these patterns, most likely either long‐distance dispersals or contractions in latitudinal distributions caused by climate change over geological timescales. We found that seed morphology varied considerably but mostly mirrored generic relationships.

H. S. Min, H. Shinwoo, and K. K. Soo. 2024. Ensemble Projection of Climate Suitability for Alfalfa (Medicago Sativa L.) in Hamkyongbukdo. Journal of The Korean Society of Grassland and Forage Science 44: 71–82. https://doi.org/10.5333/kgfs.2024.44.2.71

It would be advantageous to grow legume forage crops in order to increase the productivity and sustainability of sloped croplands in Hamkyongbukdo. In particular, the identification of potential cultivation areas for alfalfa in the given region could aid decision-making on policies and management related to forage crop production in the future. This study aimed to analyze the climate suitability of alfalfa in Hamkyongbukdo under current and future climate conditions using the Fuzzy Union model. The climate suitability predicted by the Fuzzy Union model was compared with the actual alfalfa cultivation area in the northern United States. Climate data obtained from 11 global climate models were used as input data for calculation of climate suitability in the study region to examine the uncertainty of projections under future climate conditions. The area where the climate suitability index was greater than a threshold value (22.6) explained about 44% of the variation in actual alfalfa cultivation areas by state in the northern United States. The climatic suitability of alfalfa was projected to decrease in most areas of Hamkyongbukdo under future climate scenarios. The climatic suitability in Onseong and Gyeongwon County was analyzed to be over 88 in the current climate conditions. However, it was projected to decrease by about 66% in the given areas by the 2090s. Our study illustrated that the impact of climate change on suitable cultivation areas was highly variable when different climate data were used as inputs to the Fuzzy Union model. Still, the ensemble of the climate suitability projections for alfalfa was projected to decrease considerably due to summer depression in Hamkyongbukdo. It would be advantageous to predict suitable cultivation areas by adding soil conditions or to predict the climate suitability of other leguminous crops such as hairy vetch, which merits further studies.

Zhang, H., W. Guo, and W. Wang. 2023. The dimensionality reductions of environmental variables have a significant effect on the performance of species distribution models. Ecology and Evolution 13. https://doi.org/10.1002/ece3.10747

How to effectively obtain species‐related low‐dimensional data from massive environmental variables has become an urgent problem for species distribution models (SDMs). In this study, we will explore whether dimensionality reduction on environmental variables can improve the predictive performance of SDMs. We first used two linear (i.e., principal component analysis (PCA) and independent components analysis) and two nonlinear (i.e., kernel principal component analysis (KPCA) and uniform manifold approximation and projection) dimensionality reduction techniques (DRTs) to reduce the dimensionality of high‐dimensional environmental data. Then, we established five SDMs based on the environmental variables of dimensionality reduction for 23 real plant species and nine virtual species, and compared the predictive performance of those with the SDMs based on the selected environmental variables through Pearson's correlation coefficient (PCC). In addition, we studied the effects of DRTs, model complexity, and sample size on the predictive performance of SDMs. The predictive performance of SDMs under DRTs other than KPCA is better than using PCC. And the predictive performance of SDMs using linear DRTs is better than using nonlinear DRTs. In addition, using DRTs to deal with environmental variables has no less impact on the predictive performance of SDMs than model complexity and sample size. When the model complexity is at the complex level, PCA can improve the predictive performance of SDMs the most by 2.55% compared with PCC. At the middle level of sample size, the PCA improved the predictive performance of SDMs by 2.68% compared with the PCC. Our study demonstrates that DRTs have a significant effect on the predictive performance of SDMs. Specifically, linear DRTs, especially PCA, are more effective at improving model predictive performance under relatively complex model complexity or large sample sizes.

Benson, C. W., M. R. Sheltra, P. J. Maughan, E. N. Jellen, M. D. Robbins, B. S. Bushman, E. L. Patterson, et al. 2023. Homoeologous evolution of the allotetraploid genome of Poa annua L. BMC Genomics 24. https://doi.org/10.1186/s12864-023-09456-5

Background Poa annua (annual bluegrass) is an allotetraploid turfgrass, an agronomically significant weed, and one of the most widely dispersed plant species on earth. Here, we report the chromosome-scale genome assemblies of P. annua’s diploid progenitors, P. infirma and P. supina, and use multi-omic analyses spanning all three species to better understand P. annua’s evolutionary novelty. Results We find that the diploids diverged from their common ancestor 5.5 – 6.3 million years ago and hybridized to form P. annua  ≤ 50,000 years ago. The diploid genomes are similar in chromosome structure and most notably distinguished by the divergent evolutionary histories of their transposable elements, leading to a 1.7 × difference in genome size. In allotetraploid P. annua, we find biased movement of retrotransposons from the larger (A) subgenome to the smaller (B) subgenome. We show that P. annua’s B subgenome is preferentially accumulating genes and that its genes are more highly expressed. Whole-genome resequencing of several additional P. annua accessions revealed large-scale chromosomal rearrangements characterized by extensive TE-downsizing and evidence to support the Genome Balance Hypothesis. Conclusions The divergent evolutions of the diploid progenitors played a central role in conferring onto P. annua its remarkable phenotypic plasticity. We find that plant genes (guided by selection and drift) and transposable elements (mostly guided by host immunity) each respond to polyploidy in unique ways and that P. annua uses whole-genome duplication to purge highly parasitized heterochromatic sequences. The findings and genomic resources presented here will enable the development of homoeolog-specific markers for accelerated weed science and turfgrass breeding .

Cousins-Westerberg, R., N. Dakin, L. Schat, G. Kadereit, and A. M. Humphreys. 2023. Evolution of cold tolerance in the highly stress-tolerant samphires and relatives (Salicornieae: Amaranthaceae). Botanical Journal of the Linnean Society. https://doi.org/10.1093/botlinnean/boad009

Low temperature constitutes one of the main barriers to plant distributions, confining many clades to their ancestrally tropical biome. However, recent evidence suggests that transitions from tropical to temperate biomes may be more frequent than previously thought. Here, we study the evolution of cold and frost tolerance in the globally distributed and highly stress-tolerant Salicornieae (Salicornioideae, Amaranthaceae s.l.). We first generate a phylogenetic tree comprising almost all known species (85-90%), using newly generated (n = 106) and published nuclear-ribosomal and plastid sequences. Next, we use geographical occurrence data to document in which clades and geographical regions cold-tolerant species occur and reconstruct how cold tolerance evolved. Finally, we test for correlated evolution between frost tolerance and the annual life form. We find that frost tolerance has evolved independently in up to four Northern Hemisphere lineages but that annuals are no more likely to evolve frost tolerance than perennials, indicating the presence of different strategies for adapting to cold environments. Our findings add to mounting evidence for multiple independent out-of-the-tropics transitions among close relatives of flowering plants and raise new questions about the ecological and physiological mechanism(s) of adaptation to low temperatures in Salicornieae.

Gharde, Y., R. P. Dubey, P. K. Singh, and J. S. Mishra. 2023. Littleseed canarygrass (Phalaris minor Retz.) a major weed of rice-wheat system in India is predicted to experience range contraction under future climate. International Journal of Pest Management: 1–12. https://doi.org/10.1080/09670874.2023.2199258

Modelling was carried out using maximum entropy model (MaxEnt) to explore and predict the invasion potential of littleseed canarygrass (Phalaris minor Retz.) in India under current as well as future climatic conditions under Representative Concentration Pathways (RCPs) 4.5 and 8.5 for the years 2050 and 2070. Mutually least correlated 8 bioclimatic variables along with soil and elevation data were used for the modelling over 223 occurrence locations of the species. Jackknife test revealed the significance of temperature derived variables viz. temperature seasonality, annual mean temperature and minimum temperature of the coldest month in governing the potential distribution of P. minor. Currently, 21% of India’s area is either highly (9%) or moderately (12%) suitable as habitat for P. minor. Our model predicts approximately 90% contraction in the area considered to be highly or moderately suitable climatically between 2050 and 2070 under both moderate and high emissions scenarios. Thus, under future climate, a significant niche shift by the species and decreased suitability was observed compared to the current distribution. The present study is first of its kind in exploring the invasion potential of alien invasive weed P. minor under climate change scenarios which is a current threat to rice-wheat system in Indo-Gangetic plains of India.

Escolástico-Ortiz, D. A., L. Hedenäs, D. Quandt, D. Harpke, J. Larraín, M. Stech, and J. C. Villarreal A. 2022. Cryptic speciation shapes the biogeographic history of a northern distributed moss. Botanical Journal of the Linnean Society. https://doi.org/10.1093/botlinnean/boac027

Abstract Increasing evidence indicates that wide distributed bryophyte taxa with homogeneous morphology may represent separate evolutionary lineages. The evolutionary histories of these cryptic lineages may be related to historical factors, such as the climatic oscillations in the Quaternary. Thus, the post-glacial demographic signatures paired with cryptic speciation may result in complex phylogeographic patterns. This research has two aims: to determine whether the widespread moss Racomitrium lanuginosum represents cryptic molecular taxa across the Northern Hemisphere and to infer the effects of Quaternary glaciations on spatial genetic diversity. We used the internal transcribed spacer (ITS) marker to resolve the phylogeographic history of the species and single nucleotide polymorphisms (genotyping-by-sequencing) to infer the genetic structure and demographic history. Finally, we assessed the historical changes in the distribution range using species distribution models. Racomitrium lanuginosum comprises distinct molecular lineages sympatrically distributed in the Northern Hemisphere. We also uncovered long-distance dispersal from eastern North America to Scandinavia and potential in situ survival in northern Scandinavia. Due to the genetic signatures, the Alaska Peninsula could be considered a glacial refugium. The species experienced post-glacial expansion northwards in the Northern Hemisphere, mainly from the Alaska Peninsula. Our results exemplify the complex phylogeographic history in cold environments and contribute to recognizing evolutionary patterns in the Northern Hemisphere.

Filartiga, A. L., A. Klimeš, J. Altman, M. P. Nobis, A. Crivellaro, F. Schweingruber, and J. Doležal. 2022. Comparative anatomy of leaf petioles in temperate trees and shrubs: the role of plant size, environment and phylogeny. Annals of Botany 129: 567–582. https://doi.org/10.1093/aob/mcac014

Background and Aims Petioles are important plant organs connecting stems with leaf blades and affecting light-harvesting ability of the leaf as well as transport of water, nutrients and biochemical signals. Despite the high diversity in petiole size, shape and anatomy, little information is availabl…

Mairal, M., S. L. Chown, J. Shaw, D. Chala, J. H. Chau, C. Hui, J. M. Kalwij, et al. 2021. Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub‐Antarctic. Molecular Ecology 31: 1649–1665. https://doi.org/10.1111/mec.16045

The link between the successful establishment of alien species and propagule pressure is well-documented. Less known is how humans influence the post-introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differen…