Diversification of cytoplasmic male sterility systems through somatic cell hybridization

摘要

Cytoplasmic male sterility (CMS) occurs widely in higher plants and is due to interactions between nuclear and cytoplasmic (mitochondrial)genome transcripts. Most hybrid rice currently grown is based on wild abortive cytoplasm. Using sexual crossing, CMS sources from closely related A genome Oryzae have been transferred into the nuclear background of cultivated rice. Somatic hybridization offers the ability to speed up the process of hybrid production and to produce novel nuclear-cytoplasmic combinations not possible by sexual crossing. In Japan, asymmetric protoplast fusion has been employed for the transfer of CMS to a wide range of japonica cultivars.The aim of our work is to develop, via somatic hybridization,alloplasmic lines between a range of cultivated rice and Oryza species other than A genome ones. Cell suspension cultures of O. australiensis, O. granulata, and O. latifolia have begun. Japanese studies have already produced two novel lines based on BT-type CMS and have demonstrated that somatic hybridization has considerable potential for transferring a well-established source of CMS into a broad range of cultivars. At Nottingham, a more speculative approach is being employed, which will produce more diverse CMS lines for use in rice breeding for the next millennium.