The behavior of Bupleurum scorzonerifolium as a parent of somatic hybrid introgressed lines is associated with UV resistance of its chromosomes

Abstract

Protoplasts of Bupleurum scorzonerifolium irradiated with 380 μW/cm2 UV for 5 min were fused by the PEG-mediated method with untreated protoplasts of Arabidopsis thaliana. The fusion products were cultured in the P5 liquid medium for single hybrid cell clone formation. As a total, 81 independent putative hybrid clones (cell lines) were obtained, and seventeen of them were identified as somatic hybrids by chromosome counting, GISH, RAPD, and SSR analyses. More than 80 B. scorzonerifolium-like green introgressed plants and leaves were regenerated from 49 somatic hybrid cell lines, which contained chromatin and DNA characteristic of A. thaliana. To assess the UV tolerance of both parents with chromatin exclusion and introgression, their protoplasts were UV-irradiated (380 μW/cm2 for 0 and 5 min), and the protoplasts of A. thaliana were more sensitive to UV than those of B. scorzonerifolium as judged by Single Cell Gel Electrophoresis analysis. The possible relationship between UV resistance of B. scorzonerifolium and A. thaliana chromosome elimination and the formation of somatic introgressed hybrid plants is discussed.