Anti-sense RNA efficiently inhibits formation of the 10 kd polypeptide of photosystem II in transgenic potato plants: analysis of the role of the 10 kd protein.

Abstract

A chimeric gene encoding an anti‐sense RNA of the 10 kd protein of the water‐splitting apparatus of photosystem II of higher plants under the control of the CaMV 35S promoter was introduced into potato using Agrobacterium based vectors. The expression of the anti‐sense RNA led to a significant reduction of the amounts of the 10 kd protein and RNA in a number of transgenic plants. In three out of 36 plants tested, the level of the 10 kd protein was only up to 1‐3% compared with the wild‐type control. The drastic reduction of the 10 kd protein did not influence the accumulation of other photosystem II associated polypeptides at both the RNA and protein level. Furthermore no phenotypic differences were observed between potato plants expressing wild‐type and drastically reduced levels of the 10 kd protein with respect to growth rate, habitus or ultrastructure of the chloroplasts. Measurements of the relaxation of the flash‐induced enhancement in the fluorescence quantum yield as determined in intact leaves and the rates and characteristic oscillation pattern of O2 evolution as determined in isolated thylakoid samples however, show that the elimination of the 10 kd protein on the one hand retards reoxidation of QA‐ and on the other hand introduces a general disorder into the PSII complex.

Accumulation of plant antenna complexes is regulated by post-transcriptional mechanisms in tobacco.

“…The level of antisense RNA and of detectable sense transcripts varied considerably among individual anticab and antiTP plants. A similar degree of variation has been observed earlier (Stockhaus et al, 1990;Tieman et al, 1992). The minimal steady state cab mRNA concentration is ~1% when calculated after correction for equal loading of RNA or ~5% when calculated from the 18S to cab ratio.…”

PsbR, a Missing Link in the Assembly of the Oxygen-evolving Complex of Plant Photosystem II

“…On the other hand, the characterization of PsbR antisense mutants of potato resulted in a contradictory conclusion of the PsbR protein having no effect on OEC proteins (30). However, a closer look at the Western blots of this latter study reveals a high variation in the amounts of PsbP, particularly depending on the extent of silencing of the PsbR protein in different antisense plants.…”

Formation and Deposition of Amylose in the Potato Tuber Starch Granule Are Affected by the Reduction of Granule-Bound Starch Synthase Gene Expression

“…This points toward a premature termination of transcription, which has also been reported for antisense genes for patatin (Hofgen and Willmitzer, 1992), polygalacturonase (Smith et al, 1988), andCHS (van der Krol et al, 1988). The specificity at the mRNA level of antisense RNA-mediated inhibition of gene expression has been reported for several antisense systems (Rodermel et al, 1988;Stockhaus et al, 1990;van der Krol et al, 1990), although antisense inhibition of one of the subunits of AGPase in potato was shown to affect the mRNA steady state levels of sucrose phosphate synthase and of storage protein genes (Müller-Rober et al, 1992). Because the inhibition of GBSS gene expression specifically down-regulates the biosynthesis of amylose, we concluded that antisense RNA-mediated inhibition of GBSS gene expression can be effectively applied for the suppression of the biosynthesis of amylose in potato.…”

“…The absence in individual tubers of a relationship between the GBSS mRNA steady state level and the extent of inhibition of GBSS gene expression contrasts with the presence in other antisense systems of a relation between the target mRNA level and the protein or enzyme level (van der Krol et al, 1988;Stockhaus et al, 1990;Müller-Rober et al, 1992). Tuber RNA analysis has revealed fluctuations in the GBSS mRNA steady state level in several nontransformed potato genotypes (A.G.J.…”

“…This led to the inhibition of starch synthesis in tubers and accumulation of soluble sugars. Antisense-mediated inhibition of chalcone synthase (CHS) gene expression in petunia results in a reduction of CHS protein level varying for individual transformants (van der Krol et al, 1988). Furthermore, variation in flower phenotype is observed both between and within individual transformants .…”