Premium
Post‐transcriptional gene silencing of ACC synthase in tomato results from cytoplasmic RNA degradation
Author(s) -
Lee Kathleen Y.,
Baden Catherine,
Howie William J.,
Bedbrook John,
Dunsmuir Pamela
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.12051127.x
Subject(s) - transgene , biology , gene silencing , gene , genetically modified crops , rna , polysome , ripening , gene expression , cytoplasm , microbiology and biotechnology , genetics , botany , ribosome
Summary Transgenic tomato plants with the coding region of a predominantly fruit specific ACC synthase gene ( LE‐ACS2 ) driven by the CAMV35S promoter, fall into two phenotypic classes: (i) epinastic plants and (ii) plants which appear vegetatively normal with ripening impaired fruit. In leaf tissue from epinastic plants the transgene RNA pool is high, and in the vegetatively normal plants the transgene transcript level is very low. While the epinastic phenotype results from the expected high level expression of the ACC synthase transgene throughout the plant, the vegetatively normal, ripening impaired phenotype is a consequence of the silencing of both the transgene and the corresponding endogenous gene. As in several other cases of gene silencing, the mechanism is post‐transcriptional. Transgene RNA pools are similar in nuclei of epinastic and vegetatively normal tissue. However, the transgene mRNA pool is dramatically reduced in the cytoplasm of vegetatively normal plants, and furthermore, this reduction results from degradation from the 3′ end of the transcript. This degradation probably occurs on the polysomes where the transgene transcripts are localized.