Plastid phylogenomics shed light on intergeneric relationships and spatiotemporal evolutionary history of Melocanninae (Poaceae: Bambusoideae)

Abstract

Melocanninae is sister to other subtribes of Paleotropical woody bamboos with some 90 species mainly concentrated in Asia. However, phylogenetic relationships within the subtribe are poorly known. Here, we filled the gaps in complete plastome data of Melocanninae, reconstructed the phylogeny of Melocanninae, and further estimated divergence time and ancestral distribution range. Our results showed that the two major genera, Cephalostachyum Munro and Schizostachyum Nees, were paraphyletic. Species of Cephalostachyum were resolved in two successive basal clades, whereas Annamocalamus H. N. Nguyen, N. H. Xia, & V. T. Tran was embedded in the Schizostachyum clade. Different plastid regions provided inconsistent signals for the relationship of Melocanna and Pseudostachyum. Conservative loci supported a successive divergence rather than sister relationship between them and the difference may be caused by long‐branch attraction. We infer that Melocanninae originated in the East Himalaya to northern Myanmar in the early Miocene. Three routes were revealed in forming its present biogeographic pattern: in situ diversification on the Asian mainland, dispersing southwest to Sri Lanka and to the Western Ghats in South India, and spreading southeast to Malesia and Oceania by way of the Indo‐China Peninsula. The rapid uplift of the Tibetan Plateau and the intensification of Asian monsoons since the Miocene and the sea level fall events since the Late Miocene might be potential driving forces for diversification of Melocanninae and, particularly the latter event, for the species radiation of Schizostachyum.

Grasses through space and time: An overview of the biogeographical and macroevolutionary history of Poaceae

“…Wong (monogeneric) (Soreng et al, 2017). The first‐diverging lineage of the Paleotropical woody bamboos, Melocanninae, has estimated stem and crown dates of 15.72 and 10.02 Ma, different from the crown date of 19.68 Ma (Zhou et al, 2022, this volume). Members of the subtribe share an elongated hollow style and are distributed in tropical southeast Asia and South Asia.…”

Insights into the phylogeny and chloroplast genome evolution of Eriocaulon (Eriocaulaceae)

“…Recently, more and more studies have shown that variation in chloroplast genomes provides effective information that can be used to resolve phylogenetic relationships at multiple taxonomy levels, especially in taxonomically complex groups [35,36]. For example, chloroplast genome data had resolved the systematic positions of enigmatic taxa in Saxifragales [37] and shed lights on the intergeneric relationships and spatio-temporal evolutionary history of Melocanninae (Poaceae) [36]. Moreover, the chloroplast genome sequences showed variations at the intraspecies levels, and revealed the genetic difference and diversity of endangered species [38,39] and cultivated species [40,41].…”

The biogeography of grasses (Poaceae)

“…Four of the manuscripts in this issue include new dated biogeographical analyses (Gallaher et al, 2022;Peterson et al, 2022b;Soreng et al, 2022a;Zhou et al, 2022); three comprise new phylogenetic analyses with subsequent taxonomic novelties (Da Silva et al, 2022;Peterson et al, 2022aPeterson et al, , 2022c, one is an ecological study investigating functional traits in a clade of savanna/wetland grasses (Arthan et al, 2022), one looked at the current distribution of the grasses over the Australian continent to determine migration directionality (Bryceson & Morgan, 2022), and one is an updated classification of the family primarily based on molecular phylogenetic studies (Soreng et al, 2022).…”