Genome size variation and endopolyploidy in the diverse succulent plant family Aizoaceae

Abstract

Abstract Aizoaceae are one of the most diverse succulent plant families in the world, with c. 2 400 species, and they are a major component of the Greater Cape Floristic Region of South Africa. Despite this diversity, genome size (GS) has only been recorded in three of the c. 144 genera of Aizoaceae. This study provides the first comprehensive assessment of GS in the family with 109 genera measured (76% of genera). GS (2C) is conserved in Aizoaceae, varying from 0.54 to 6.34 pg (0.53–6.20 Gbp), with a mean of 2.6 pg. No significant differences between GS and the ecological and environmental traits tested were recovered. Infrageneric GS was explored in the most diverse stoneplant genus, Conophytum, and was found to be extremely conserved [0.98–2.24 pg (1C)]. Furthermore, the extent of endoreduplication in Conophytum was determined across 46 species. Leaf and flower tissues of Conophytum are highly polysomatic and ploidy states of 2C–64C were typically observed across the genus, with some instances of 128C. The relatively conserved and small GS measured across Aizoaceae and in Conophytum is possibly linked to the recent and rapid radiation of the family.