VIEW ARTICLE

Effect of Rust Infection of Oat Leaves on Cytoplasmic and Chloroplast Ribosomal Ribonucleic Acids. T. Tani, Laboratory of Plant Pathology, Faculty of Agriculture, Kagawa University, Kagawa 761-07, Japan; M. Yoshikawa(2), and N. Naito(3). (2)(3)Laboratory of Plant Pathology, Faculty of Agriculture, Kagawa University, Kagawa 761-07, Japan, (2)Present address: Department of Plant Pathology, University of California, Riverside 92502. Phytopathology 63:491-494. Accepted for publication 2 October 1972. DOI: 10.1094/Phyto-63-491.

In the susceptible oat cultivar, ‘Victoria’, the ratio of cytoplasmic ribosomal ribonucleic acid (rRNA) between inoculated and noninoculated control leaves increased slightly from 1.10 to 1.17, respectively, 2 and 3 days after inoculation, followed by a more pronounced increase of 1.62 and 2.14, 4 and 6 days after. By contrast, the chloroplast rRNA increased to 1.02 and 1.06, respectively, 2 and 3 days after inoculation, then decreased to 0.70 and 0.53, 4 and 6 days afterwards. The ratio of incorporation of ³²P into rRNA increased to about 1.3 for both cytoplasmic and chloroplast fractions 2 days after inoculation, but at 4 days, the cytoplasmic fraction increased to 1.81, whereas the chloroplast fraction remained unaltered. In the highly resistant cultivar ‘Shokan 1’, the ratios of cytoplasmic and chloroplast rRNA between inoculated and noninoculated controls did not change during the period when the resistant reaction occurred (28 and 48 hr after inoculation). The incorporation of ³²P into rRNA, however, increased in both fractions 1.57 to 1.81 times that of the noninoculated control.