Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2007
Publication Date: 7/20/2007
Citation: Castillo, N.F., Reed, B.M., Bassil, N.V. 2007. Fingerprinting and Genetic Stability of Rubus Using Molecular Markers. HortScience. 42(4):914.
Interpretive Summary: The United States Department of Agriculture (USDA) - Agricultural Research Service (ARS) - National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, preserves 2094 blackberries, raspberries and relatives. This collection represents 193 species originating from 64 countries. In this study, 13 Simple Sequence Repeat (SSR) molecular markers were developed and generated a unique fingerprint for 96 types of blackberry, raspberry, hybrids and unusual species relatives chosen from the collection. Two types of molecular markers, Amplified Fragment Length Polymorphisms (AFLPs) and SSRs were also used to evaluate the genetic stability of small shoots preserved under long-term storage conditions in liquid nitrogen for over 12 years. AFLP markers detected variation in three out of the four varieties that were propagated in tissue culture for seven months while no variation was detected in those analyzed immediately after recovery from long-term storage. Such variation might have been generated from unorganized plant tissue during propagation. The new SSR markers will be used to fingerprint additional blackberry and raspberry relatives and will assist genebank managers, nurserymen and growers in verifying the identity of plants. The stability of the variation observed in the three plant types regenerated after long term storage will be investigated further after growth in the field.
Technical Abstract: DNA markers were used to identify raspberries and blackberries and to evaluate genetic stability of four cryopreserved Rubus accessions following 12 years of storage in liquid nitrogen. In the first study, 12 genomic Simple Sequence Repeat (SSR) markers and one Expressed Sequence Tag- (EST)-SSR were used to fingerprint 48 raspberry and 48 blackberry cultivars stored at the United States Department of Agriculture (USDA) - Agricultural Research Service (ARS) - National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon. The Rubus SSR markers were polymorphic and distinguished between the raspberry and blackberry cultivars but not between clones like ‘Logan’ or ‘Boysen’ sports. In the second study, SSRs and Amplified Fragment Length Polymorphisms (AFLP) were used to evaluate genetic fidelity of Rubus shoot tips that were regrown following 12 years of cryostorage in liquid nitrogen. SSR analysis using 10 markers failed to detect variation in any of the regenerated shoots. AFLP revealed polymorphism in three out of the four Rubus genotypes that were subcultured for seven months while no polymorphism was detected in those analyzed immediately after recovery from cryopreservation. Such polymorphism might have been generated through somaclonal variation, possibly from callus tissue during propagation. This variation will be investigated using additional morphological and molecular analysis of adult regrown cryopreserved plants.