Abstract.
Nicotiana sylvestris Speg. & Comes transformed with a tobacco class-I β-1,3-glucanase (GLU I ) cDNA driven by CaMV 35S RNA expression signals exhibits posttranscriptional gene silencing (PTGS) which is triggered between the cotyledon and two-leaf stages of seedling development and is postmeiotically reset to the high-expressing state during seed development. The incidence of GLU I PTGS in sibling plants differed for the two different transformants tested and increased with the number of T-DNA loci. Comparison of host class-I and class-II β-1,3-glucanase gene expression suggests that a similarity of 60–70% in the coding-region is required for PTGS of the homologous host genes. The GLU I transformants exhibited a spatial gradient in PTGS, in which expression of the silent phenotype gradually increased in successive leaves toward the bottom of the plant. In contrast, transformants carrying an unrelated tobacco class I chitinase (CHN I ) cDNA in the same expression vector exhibited discontinuous patterns of PTGS with adjacent high-expressing and silent leaves. The GLU I- and CHN I-specific patterns were maintained in hybrids homozygous for both T-DNA's indicating that two different transgenes present in the same genome can exhibit independent and distinctive patterns of PTGS. This implies that the nature of the transgene rather than a general pre-pattern of competence for PTGS or propagation of the silent state are important for pattern determination.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 26 February 2000 / Accepted: 17 May 2000
Rights and permissions
About this article
Cite this article
Kunz, C., Schöb, H., Leubner-Metzger, G. et al. β-1,3-Glucanase and chitinase transgenes in hybrids show distinctive and independent patterns of posttranscriptional gene silencing. Planta 212, 243–249 (2001). https://doi.org/10.1007/s004250000383
Issue Date:
DOI: https://doi.org/10.1007/s004250000383