Yu Ito, Yuki Tamura, Yukiko Saito, Hiroshi Ikeda, Kyong-Sook Chung, Hyoung-Tak Im, Keshab Raj Rajbhandari, Tian-Chuan Hsu, Okihito Yano
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Abildgaardia ovata (Cyperaceae) is a widely distributed herbaceous plant found in tropical to warm-temperate regions, including East, South-east and South Asia, Oceania, Africa and Central and South America. Preliminary data suggested intraspecific diversity in A. ovata in Japan; thus, we investigated the genetic diversity of A. ovata using chloroplast DNA and the internal transcribed spacers of nuclear ribosomal DNA (nrITS) sequence data and analysed its distribution patterns and morphological traits. Further, we observed its chromosomes. We identified two distinct major lineages with slightly overlapping yet unique distribution patterns, one in Japan’s Honshu, Kyushu, Nansei, Korea’s Jeju Isl. and Nepal, while the other was restricted to Nansei and Taiwan. Species delimitation analysis supported the existence of two A. ovata intraspecies. Ecological niche modelling further suggested ecological differentiation between the two intraspecies. Samples with heterogeneous nrITS sequences were also found in Nansei where the two species are distributed; those may have resulted from hybridisation between the above-mentioned two intraspecies. Other samples with heterogeneous nrITS distributed in Kyushu. With respect to chromosome numbers, the former is a homoploid hybrid between 2n = 20 intraspecies while the latter is an allopolyploid with 2n = 40. Together, we identified novel cryptic diversity within the widespread polyploid species complex; however, the lack of diagnostic characters precludes formal description at this point. Further taxon sampling and additional genetic analyses may reveal whether the more narrowly distributed lineage differentiated from the widely distributed one in Asia.
Research papers (academic journals)
