American Journal of BotanyVolume 108, Issue 9 p. 1577-1579 NEWS & VIEWSFree Access A quick glance at noteworthy articles for September 2021 First published: 28 September 2021 https://doi.org/10.1002/ajb2.1741AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat WHEN SHARING ISN'T CARING: DRIVERS OF BETWEEN-SPECIES POLLEN TRANSFER AND ITS EFFECTS ON REPRODUCTION Plant species in a community can inadvertently exchange pollen when they rely on shared pollinators. Recent work indicates that this “heterospecific pollen transfer” is common but varies dramatically, even among individuals within species. The drivers of variation for this phenomenon and its consequences for reproduction in wild plant populations remain unclear. Smith et al. examined the causes and fitness consequences of heterospecific pollen receipt in Oenothera fruticosa. They find that pollinator type, the composition of nearby flowering plants, the interaction between those two factors, and the timing of flowering all influence the amount of heterospecific pollen received. Natural levels of heterospecific pollen receipt are great enough to reduce seed production, but the negative impact is abated when large amounts of Oenothera pollen is also present. These results suggest that although some plant traits reduce heterospecific pollen receipt, community context has as great an influence, favoring a tolerance strategy. References Gerard X. Smith et al. 2021. Causes and consequences of variation in heterospecific pollen receipt in Oenothera fruticosa. American Journal of Botany. https://doi.org/10.1002/ajb2.1720Google Scholar ASSOCIATIONS WITH MYCORRHIZAL FUNGI ARE MORE COMMON AMONG HAWAIIAN NATIVE PLANT SPECIES THAN AMONG CONTINENTAL SPECIES The mutualism between root-inhabiting fungi and plants, known as mycorrhizae, is common across most plant families and throughout the world. However, due to their age and isolation, remote oceanic islands such as Hawaiʻi have been predicted to harbor fewer mycorrhizal host plant species than mainlands. In a survey of 35 native Hawaiian plant species across the island of Oʻahu, Koko et al. found new evidence that the prevalence of the mycorrhizal symbiosis is actually much higher than continental averages on one of the most remote and youngest islands on earth. The survey focused on host plant species of conservation concern or commonly used in ecological restoration, and the results suggest that integrating these symbionts into future restoration practices could potentially increase their success, especially in regions such as Hawaiʻi where mycorrhizal species dominate the native flora. References Jerry H. Koko et al. 2021. Hawaiian Island endemic and indigenous plant species have. higher mycorrhizal incidence than the global average. American Journal of Botany. https://doi.org/10.1002/ajb2.1731Wiley Online LibraryPubMedWeb of Science®Google Scholar GENETIC SEQUENCING PROVIDES INSIGHT INTO THE RECENT EVOLUTION OF CHESTNUTS AND CHINQUAPINS IN NORTH AMERICA Although Chestnuts and Chinquapins (Castanea spp.) are well known, widely loved trees, their evolutionary history remains poorly understood. Using genetic sequencing and species distribution models, Spriggs and Fertakos infer the phylogeny of Castanea and delve into the recent history of the two North American lineages. Within the American Chestnut, there is a pattern of sequential northward migration with the most diverse populations found at the southern end of the range in Georgia. Meanwhile, multiple population clusters were identified in the Chinquapins, including one group that corresponds to the frequently recognized Castanea pumila var. ozarkensis. These results provide important context for ongoing conservation and restoration efforts that follow the devastating impact of the Chestnut Blight in North America, and the populations highlighted by this study will be valuable for future breeding programs. References Elizabeth L. Spriggs and Matthew E. Fertakos. 2021. Evolution of Castanea in North America: restriction-site-associated DNA sequencing and ecological modeling reveal a history of radiation, range shifts, and disease. American Journal of Botany. https://doi.org/10.1002/ajb2.1726Wiley Online LibraryPubMedWeb of Science®Google Scholar DEPAUPERATE LINEAGES WITH CONTINENT-SPANNING DISJUNCT DISTRIBUTIONS ARE LEGACIES OF ANCIENT CLIMATE CHANGE Taxa with few species but widespread, geographically discontinuous distributions are intriguing. Why are they species-poor? How did they achieve their broad, disjunct distribution? Culshaw et al. reconstruct the evolutionary history of Camptoloma, a genus of flowering plants with three species found in distant margins of the African continent: the Canary Islands in the west, Somalia-southern Arabia in the east, and Namibia in the south. This distribution is known as the Rand Flora, a biogeographic pattern observed in multiple angiosperm families, in which sister species occur in a ring around Africa, separated by thousands of kilometers of desert and tropical lowlands. Genetic and genomic data from the plastid and nuclear genomes reveal that Camptoloma's “extreme” distribution was the result of fragmentation and extinction/population bottlenecking events associated with historical aridification cycles dating back to the Early Miocene. The narrow distributions, high habitat specificity, and small population sizes of the three extant species make them vulnerable to anthropogenic activities and of high conservation value. References Victoria Culshaw et al. 2021. Rare and widespread: integrating Bayesian MCMC approaches, Sanger sequencing and Hyb-Seq phylogenomics to reconstruct the origin of the enigmatic Rand Flora genus Camptoloma. American Journal of Botany. https://doi.org/10.1002/ajb2.1727Wiley Online LibraryPubMedWeb of Science®Google Scholar METABARCODING REVEALS HIDDEN MICROBIAL DIVERSITY IN HORNWORTS Hornworts (Anthocerophyta) are the only plant phylum in which all species form specialized nitrogen-fixing symbioses. The interactions between a few hornworts and their nitrogen-fixing Nostoc cyanobacterial symbionts have been studied for decades, but the environmental diversity of cyanobacterial partners and the ecological factors impacting these communities are still largely unknown. Using long-read metabarcoding methods, Nelson et al. reveal a broad phylogenetic diversity of cyanobacteria living in three species of temperate hornworts. This diversity goes far beyond the genus Nostoc and also beyond clades previously known to contain plant symbionts. These diverse cyanobacterial communities lack a strong signal of host hornwort specificity but do show a strong similarity to the cyanobacteria in surrounding soils. The communities are also apparently quite dynamic, as they vary stochastically over the growing season and across short physical distances. References Jessica M. Nelson et al. 2021. The diversity and community structure of symbiotic cyanobacteria in hornworts inferred from long-read amplicon sequencing. American Journal of Botany. https://doi.org/10.1002/ajb2.1729Wiley Online LibraryWeb of Science®Google Scholar Volume108, Issue9September 2021Pages 1577-1579 ReferencesRelatedInformation