A recent study in the Plant Genetic Engineering Laboratory (PGEL) at the University of Queensland has resulted in a mutant Arabidopsis line with highly desirable agricultural traits. This line has been named ‘PLENTIFUL’ because of its striking phenotype of unusually high numbers of leaves and flowers. Compared to wildtype Arabidopsis, PLENTIFUL is bushier, more compact and has delayed flowering.(LEFT) Wildtype Arabidopsis with the normal number of flowers, and
(RIGHT) PLENTIFUL with the highly desirable trait of many more
flowers.
PLENTIFUL was created by over-expressing a gene belonging to a large family of transcription factors in Arabidopsis thaliana. This family of transcription factors are basic helix-loop-helix (bHLH) proteins which form hetero- or homo- dimers with other bHLH proteins and bind to DNA to activate transcription. PLENTIFUL is part of a subfamily of bHLH proteins that cannot bind to DNA. It is predicted that members of this subfamily dimerise with DNA-binding bHLH proteins to prevent transcription.
The exciting results of the PLENTIFUL study have lead to current research characterising more genes in the non-DNA-binding subfamily of bHLH proteins.
Although the over-expressed gene responsible for PLENTIFUL is yet to be definitively characterised, the delayed flowering phenotype poses the idea that it may be involved in a flowering pathway. The delayed flowering of PLENTIFUL explains the bushier phenotype with more leaves but the most exciting thing is that PLENTIFUL also has more flowers! Having both more flowers and more leaves is a trait that is highly desired in agriculture and it appears that through manipulating transcription factors and the complex networks they regulate, it will be possible to enhance the yield of economically important crops.
References:
Ferris, R, Plentiful’s Tale (2001). Honours thesis, University of Queensland
Gabriela Toledo-Ortiz, Enamul Huq,and Peter H. Quail (2003) The Arabidopsis Basic/Helix-Loop-Helix Transcription Factor Family. The Plant Cell, Vol. 15, 1749–1770
Gabriela Toledo-Ortiz, Enamul Huq, and Peter H. Quail (2003) Supplementary Material Table 2. AtbHLH proteins predicted to be Non-DNA-binders.
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