Anastatica hierochuntica L., the True Rose of Jericho, is a monotypic genus endemic to the Saharo-Arabian deserts. This annual plant is an extremophyte, exhibiting exceptional tolerance to drought, high salinity, and intense solar radiation. It has evolved a unique hygrochastic seed dispersal mechanism, forming persistent aboveground seed banks that enable rapid germination following rare rainfall events. Cytogenomic studies have revealed that Anastatica underwent a lineage-specific whole-genome duplication followed by descending dysploidy from 2n = 32 to 2n = 22, accompanied by extensive chromosome repatterning. These features make it an ideal model for studying genome evolution and adaptation to arid environments.
Here, chromosome numbers were determined in 32 populations of Anastatica hierochuntica sampled across its distribution range. This broad sampling was designed to capture potential cytotypic variation across geographically and ecologically distinct regions, especially given the species’ fragmented distribution and hypothesized historical disjunctions. All analyzed individuals exhibited a chromosome number of 2n = 22, consistent with previous cytogenetic report. No aneuploidy or B chromosomes were observed. The uniformity of chromosome number across all populations supports the hypothesis of a stabilized post-polyploid genome structure in this mesohexaploid lineage, despite its ecological breadth and evolutionary history.
