MICROPROTOPLAST FUSION TECHNIQUE - A NEW TOOL FOR GENE-TRANSFER BETWEEN SEXUALLY-INCONGRUENT PLANT-SPECIES

Various aspects of a microprotoplast fusion technique and the strategi es followed for intergeneric partial genome transfer (one or a few chr omosomes) and alien genes from sexually-incongruent donor species to r ecipient species are described. The essential requirements of the micr oprotoplast fusion technique are the induction of micronuclei at high frequencies, as well as the isolation and enrichment of sub-diploid mi croprotoplasts in donor species, efficient fusion of the donor micropr otoplasts with normal recipient protoplasts and stable regeneration of plants from fusion products. The results on the production of micropr otoplast hybrid plants between the transformed donor lines of Solanum tuberosum and Nicotiana plumbaginifolia carrying various genetic marke rs, and a recipient line of Lycopersicon peruvianum or Nicotiana tabac um, and on the transfer and expression of alien genes (kanamycin resis tance, beta-glucuronidase) are presented. The data obtained on micropr otoplast hybrid plants between S. tuberosum and L. peruvianum showed t hat many of the hybrids contained one potato chromosome carrying nptII and GUS, and 24 or 48 L. peruvianum chromosomes (monosomic additions) , and that they were male- and female-fertile. Various applications of chromosome transfer by this technique, especially for economically-im portant traits (e.g. disease or stress resistance) from sexually-incom patible wild species, for construction of chromosome-specific DNA libr aries through microdissection and microcloning of chromosomes, or by f low-sorting of chromosomes for genome analysis, are discussed.