New Phytologist Editors’ Choice: November 2014, 204:3
Last updated: 17 Oct, 2014
New clues to the molecular basis of vegetative regeneration in plants
Ckurshumova W, Smirnova T, Marcos D, Zayed Y, Berleth T. 2014. Irrepressible MONOPTEROS/ARF 5 promotes de novo shoot formation. New Phytologist 204: 557–567.
Vegetative propagation from organs, tissues or even individual cells is an amazing property of plants. Indeed, animal stem cell researchers should be green with envy given the ease at which some plant cells can be coaxed to divide, differentiate, and produce new organs. However, many plants are recalcitrant to vegetative propagation, and the reason why some plants perform well and others do not is not clear. Indeed, surprisingly little is known about the fundamental processes regulating vegetative reproduction, although it is clear that the plant hormones auxin and cytokinin are important.
The experiments in this paper from the Berleth lab provide critical new insights into how auxin affects regeneration and shoot formation from callus in Arabidopsis. The Arabidopsis transcription factor, MONOPTEROS/AUXIN RESPONSE FACTOR5 (MP), is a key mediator of auxin response and cytokinin signaling. In this work, MP was shown to be expressed in daughter cells of root primordia, as well as in cells giving rise to shoots from callus cultures. Mutants lacking MP performed poorly in regenerating shoots from callus cultures. In contrast, mutants expressing a MP that lacks a domain involved in negative regulation of MP (i.e. is irrepressible) excelled at producing shoots from callus. Together these results provide insights into the mechanisms underlying vegetative propagation, and also provide a key target gene that can be targeted to increase vegetative propagation success in recalcitrant species.
Vegetative propagation faithfully preserves the genotype of the plant, and is widely used to maintain valuable horticultural varieties, and provide clonal plants for agriculture and forestry. Importantly, vegetative propagation does not involve sexual reproduction or recombination, and all of the genetic gains realized in a superior individual can be captured and deployed in commercial plantings. This new research has the potential for major impacts for agriculture and plant research.
Andrew Groover, Editor New Phytologist
US Forest Service, Davis CA 95618, USA
Originally posted 17 October 2014