Molecular Evidence for Bidirectional Hybrid Origin and Hippophae rhamnoides ssp. sinensis as the Mainly Maternal Plant of the Diploid Hybrid H.goniocarpa(Elaeagnaceae)
Abstract:Hippophae goniocarpa is a natural hybrid species through homoploid hybridization between H.rhamnoides ssp. sinensis and H.neurocarpa distributed sympatrically. Maternally inherited cpDNA trnS-G sequence was used to detect the genetic relationship among 93 individuals of H.goniocarpa and its parent species which distributed sympatrically in Gongbeiwan and river land of Babao of Qilian, Qinghai. The results showed that H.goniocarpa and its parent species in the Gongbeiwan and river land of Babao had 12 and 7 haplotypes, respectively. H.goniocarpa shared common haplotypes with both H.rhamnoides ssp. sinensis and H.neurocarpa in the two places. Twenty-eight out of 36 individuals of H.goniocarpa shared common haplotypes with H.rhamnoides ssp. sinensis(H2, H4, H5), only two individuals shared common haplotypes with H.neurocarpa at Gongbeiwan. Seven out of 10 individuals of H.goniocarpa shared common haplotypes with H.rhamnoides ssp. sinensis(H4), 3 out of 10 individuals of H.goniocarpa shared common haplotypes with H.neurocarpa(H7) at river land of Babao. Phylogenetic tree of H.goniocarpa and its parent species from two regions was constructed by Maximum Parsimony (MP), and the results showed that most individuals of H.goniocarpa were clustered together with H.rhamnoides ssp. sinensis. In addition, 6 individuals of H.goniocarpa with 4 typical haplotypes (H3, H7, H8 and H9) were also clustered with H.rhamnoides ssp. sinensis. The bidirectional hybrid origin of H.goniocarpa is further proved here and H.rhamnoides ssp. sinensis is found to be the main maternal source.