Mahin Abedinia

The use of microsatellite polymorphisms for the identification of Australian breeding lines of rice (Oryza sativa L.)

Ten microsatellite loci were analysed for 43 cultivars or breeding lines of rice. Polymorphism-Information-Content values ranged from 0.62 to 0.92. The microsatellite markers were found to be useful for cultivar identification and assessment of genetic relationships. Most of the cultivars could be uniquely identified by at least one microsatellite marker. Genetic heterogeneity was detected within rice samples by amplification of microsatellites from DNA extracted from multiple individual plants and also from bulked DNA preparations.

An efficient transformation system for the Australian rice cultivar, Jarrah

A rapid and efficient transformation system for the generation of large numbers of transformed, fertile, transgenic rice (Oryza sativa L.) plants of the Australian rice cultivar, Jarrah, is described. Embryogenic callus pieces derived from mature seeds were bombarded with gold particles coated with DNA. Two plasmids were used, one containing a gene encoding hygromycin phosphotransferase (hph, conferring hygromycin resistance) as a selectable marker and the other containing uidA (gus) as a reporter gene. The calli were selected for their resistance to hygromycin. DNA uptake, integration and expression of the hph and gus gene in selected rice were investigated by various PCR methods and dot blot and Southern analysis of genomic DNA extracted from transformed rice plants. On average one independently transformed hygromycin resistant plant was recovered from every 2.4 pieces of callus bombarded. Selection with Biolaphos using the Bar gene as selectable marker was not successful in this system.

Accessing genes in the tertiary gene pool of rice by direct introduction of total DNA from Zizania palustris (wild rice)

Transfer of useful genes from wild relatives of crop plants has relied upon successful conventional crossing or the availability of the cloned gene. Co-bombardment of rice callus with total genomic DNA from wild rice (Zizania palustris) and a plasmid containing a gene confirming hygromycin resistance allowed recovery under selection of transgenic plants with grain characteristics from wild rice. Amplified Fragment Length Polymorphism (AFLP) analysis suggested that a significant amount of DNA fromZizania was introduced by this procedure. One plant had 16 of a possible 122Zizania specific AFLP markers detected with the primers used. This approach may have potential for introgression of genes from wild relatives in other cases where highly efficient transformation methods are available.

Distribution and phylogeny of Potamophila parviflora R. Br wild rice from eastern Australia

Potamophila parviflora is a wild relative of rice from Eastern Australia. The species was found in the Richmond, Clarence, Macleay and Hastings River systems of northern New South Wales. Existing populations had wider leaves (10–15 mM) than those previously reported (4–6 mM). This species and North American wild rice, Zizania palustris were investigated as genetic resource for rice improvement. Both species, Potamophila , and Zizania , occur in colder climates than rice (Oryza sativa). Sequencing of the ITS1 of the ribosomal genes of these two species indicated that Zizania and Potamophila were more closely related to each other than either was to Oryza sativa. Potamophila has a similar number of chromosomes (n=12) and a greater sequence homology to rice and may thus be a better source of useful genes for rice improvement.