Bünger W, Feierabend J. Capacity for RNA synthesis in 70S ribosome-deficient plastids of heat-bleached rye leaves.
PLANTA 1980;
149:163-169. [PMID:
24306248 DOI:
10.1007/bf00380878]
[Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/1979] [Accepted: 01/23/1980] [Indexed: 06/02/2023]
Abstract
In the leaves of rye seedlings (Secale cereale L.) grown at an elevated temperature of 32°C the formation of plastidic 70S ribosomes is specifically prevented. The resulting plastid ribosome-deficient leaves, which are chlorotic in light, represent a system for the identification of translation products of the 80S ribosomes among the chloroplastic proteins. Searching for the primary heat-sensitive event causing the 70S ribosome-deficiency, the thermostability of the chloroplastic capacity for RNA synthesis was investigated. The RNA polymerase activity of isolated normal chloroplasts from 22°-grown rye leaves was not inactivated in vitro at temperatures between 30° and 40°C. The ribosome-deficient plastids purified from bleached 32°-grown leaf parts contained significant RNA polymerase activity which was, however, lower than in functional chloroplasts. After application of [(3)H]uridine to intact leaf tissues [(3)H]uridine incorporation was found in ribosome-deficient plastids of 32°C-grown leaves. The amount of incorporation was similar to that in the control chloroplasts from 22°C-grown leaves. According to these results, it is unlikely that the non-permissive temperature (32°C) causes a general inactivation of the chloroplastic RNA synthesis in rye leaves.
Collapse