The unprecedented wheat yield increases during the Green Revolution were achieved through the introduc-tion of the Reduced height(Rht)-B1b and Rht-D1b semi-dwarfing alleles.These Rht-1 alleles encode growth-repressing...The unprecedented wheat yield increases during the Green Revolution were achieved through the introduc-tion of the Reduced height(Rht)-B1b and Rht-D1b semi-dwarfing alleles.These Rht-1 alleles encode growth-repressing DELLA genes containing a stop codon within their open reading frame that confers gibberellin(GA)-insensitive semi-dwarfism.In this study,we successfully took the hurdle of detecting wild-type RHT-1 proteins in different wheat organs and confirmed their degradation in response to GAs.We further demonstrated that Rht-B1b and Rht-D1b produce N-terminal truncated proteins through trans-lational reinitiation.Expression of these N-terminal truncated proteins in transgenic lines and in Rht-D1c,an allele containing multiple Rht-D1b copies,demonstrated their ability to cause strong dwarfism,resulting from their insensitivity to GA-mediated degradation.N-terminal truncated proteins were detected in spikes and nodes,but not in the aleurone layers.Since Rht-B 1b and Rht-D1b alleles cause dwarfism but have wild-type dormancy,this finding suggests that tissue-specific differences in translational reinitiation may explain why the Rht-1 alleles reduce plant height without affecting dormancy.Taken together,our findings not only reveal the molecular mechanism underlying the Green Revolution but also demonstrate that trans-lational reinitiation in the main open reading frame occurs in plants.展开更多
基金D.V.D.S.acknowledges Ghent University for financial support.S.T.was supported by the Biotechnology and Biological Sciences Research Council Designing Future Wheat Cross Institute Strategic Programme(grant BB/P016855/1).
文摘The unprecedented wheat yield increases during the Green Revolution were achieved through the introduc-tion of the Reduced height(Rht)-B1b and Rht-D1b semi-dwarfing alleles.These Rht-1 alleles encode growth-repressing DELLA genes containing a stop codon within their open reading frame that confers gibberellin(GA)-insensitive semi-dwarfism.In this study,we successfully took the hurdle of detecting wild-type RHT-1 proteins in different wheat organs and confirmed their degradation in response to GAs.We further demonstrated that Rht-B1b and Rht-D1b produce N-terminal truncated proteins through trans-lational reinitiation.Expression of these N-terminal truncated proteins in transgenic lines and in Rht-D1c,an allele containing multiple Rht-D1b copies,demonstrated their ability to cause strong dwarfism,resulting from their insensitivity to GA-mediated degradation.N-terminal truncated proteins were detected in spikes and nodes,but not in the aleurone layers.Since Rht-B 1b and Rht-D1b alleles cause dwarfism but have wild-type dormancy,this finding suggests that tissue-specific differences in translational reinitiation may explain why the Rht-1 alleles reduce plant height without affecting dormancy.Taken together,our findings not only reveal the molecular mechanism underlying the Green Revolution but also demonstrate that trans-lational reinitiation in the main open reading frame occurs in plants.
