Population genomics reveal apomixis in a novel system: uniclonal female populations dominate the tropical forest herb family, Hanguanaceae (Commelinales). Issue 6 (24th September 2020)

• Record Type: Journal Article
• Authors: Niissalo, Matti A; Leong-Škorničková, Jana; Šída, Otakar; Khew, Gillian S
• Editors: Brennan, Adrian
• Is Part Of: AoB plants. Volume 12:Issue 6(2020)
• Publication Date: 2020-09-24
• Subjects: Apomixis -- chromosome count -- clonality -- Commelinales -- ddRADseq -- genome size -- Hanguana; Plants -- Periodicals; Botany -- Periodicals; 580.5
• DOI: 10.1093/aobpla/plaa053
• Languages: English
• ISSNs: 2041-2851

Abstract

Abstract: The abundance of apomixis in tropical plant genera is poorly understood, and this affects the understanding of speciation and evolution. Hanguanaceae is a tropical monogeneric, dioecious plant family. All but two species are solitary herbs with no capability to spread vegetatively. Viable seeds are often produced when males have not been observed. Our aim was to investigate the presence of apomixis in Hanguana . We used reduced representation genomics to study phylogenetics and genetic variability in all populations of Hanguana in Singapore. We measured genome sizes and estimated ploidy levels in 10 species. Almost all taxa tested were genetically uniform (uniclonal) regardless of the extent of their distribution. The distribution of single clones over distinct localities supports our hypothesis of apomictic reproduction. Only one sexually reproducing native species was detected. Triploid and pentaploid states support our hypothesis that the type of apomixis in Hanguana is gametophytic. Population genomics tools offer a quick and cost-effective way of detecting excess clonality and thereby inferring apomixis. In the case of Hanguana, the presence of male plants is a strong indicator of sexual reproduction, whereas genome triplication is indicative of apomictic reproduction. Abstract : We used reduced representation genomics to observe population diversity in the dioecious herb genus Hanguana in Singapore. Our results suggest that most of the studied species reproduce exclusively via apomictic seeds, and form populations that are composed of single, widely distributed clones. This explains a lack of records of male plants in the area. The relationships of apomictic clones to sexual populations, for example possible hybridization, require further study. Apomictic clones of Hanguana are associated with uneven ploidy levels.