Polyploidy plays an important role in plant evolutionary processes. Despite extensive studies, the association between polyploidy and species diversification remains difficult to interpret.
In a recent issue of journal New Phytologist, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) reported a study providing new insights into the effect of polyploidy on diversification, considering both the effects of intraspecific polyploid frequency and habitat or trait shifts.
The researchers examined the relationship between intraspecific polyploid frequency and diversification in Allium (one of the largest monocotyledonous genera in the family Amaryllidacea) and its association with shifts in habitats or traits.
They built a phylogeny of 448 Allium species (representing 46% of the total) by using eight plastid and nuclear ribosomal markers.
Using trait‐dependent diversification models, the researchers quantified intraspecific ploidy diversity, heterogeneity in diversification rates, and their relationship along the phylogeny. They then evaluated the association between polyploidization and habitat or trait shifts.
They showed that Allium lineages with high polyploid frequencies had increased diversification or speciation rates in conjunction with habitat shifts under particular soil conditions.
“We also detected a significant polyploidy-related diversification rate shift in East Asia”, said Prof. XING Yaowu, principal investigator of the study.
“Our results suggest that the intraspecific frequency of polyploidy is a determinant of the rate of polyploid speciation and ecological radiation in Allium, which may explain plant radiations more generally”, said Prof. XING.
XING Yaowu Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
Phylogenetic reconstruction of Allium. (Image by HAN Tingshen)