Structural changes in the plastid DNA of rice (Oryza sativa L.) during tissue culture

• Published in: Theoretical and applied genetics Vol. 90; no. 3-4; pp. 364 - 371
• Main Authors: Kawata, M, Ohmiya, A, Shimamoto, Y, Oono, K, Takaiwa, F. (Forage Crop Breeding and Seed Research Inst., Nishinasuno (Japan))
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-03-1995; Berlin
• Subjects: ADN; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; Biological and medical sciences; CHLOROPLASTE; CITOLOGIA; Classical genetics, quantitative genetics, hybrids; CLOROPLASTO; CULTIVO DE TEJIDOS; CULTURE DE TISSU; CYTOLOGIE; Deletion; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; ORYZA SATIVA; Pflanzenzuechtung; Plastid DNA; Plastid morphology; ptDNA; Pteridophyta, spermatophyta; Vegetals; Monocotyledones; Callus; Chloroplast DNA; Tissue culture; Plastid; Cereal crop; Oryza sativa; Gramineae; Ultrastructure; Angiospermae; Gene rearrangement; Deletion; Spermatophyta; Mutation
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/BF00221978

To investigate the rearrangement of the plastid genome during tissue culture, DNA from rice callus lines, which had been derived individually from single protoplasts isolated from seed or pollen callus (protoclones), was analyzed by Southern hybridization with rice chloroplast DNA (ctDNA) clones as probes. Among 44 long-term cultured protoclones, maintained for 4, 8 or 11 years, 28 contained plastid DNA (ptDNA) from which portions had been deleted. The ptDNA of all protoclones that had been maintained for 11 years had a deletion that covered a large region of the plastid genome. The deletions could be classified into 15 types from their respective sizes and positions. By contrast, no deletions were found in the ptDNA of 38 protoclones that had been maintained for only 1 month. These results indicate that long-term culture causes deletions in the plastid genome. Detailed hybridization experiments revealed that plastid genomes with deletions in several protoclones were organized as head-to-head or tail-to-tail structures. Furthermore, ptDNAs retained during long-term culture all had a common terminus at one end, where extensive rearrangement is known to have occurred during the speciation of rice and tobacco. Morphological analysis revealed the accumulation of starch granules in plastids and amyloplasts in protoclones in which the plastid genome had undergone deletion. These observations indicated that novel structural changes in the plastid genome and morphological changes in the plastid had occurred in rice cells during long-term tissue culture. Moreover, the morphological changes in plastids were associated with deletions in the plastid genome.