Flowers aren't just pretty to look at, they are how plants reproduce. In agricultural plants, the timing and regulation of flower formation has economic significance, affecting a crop's yield.
A new paper by researchers at the University of Pennsylvania published in the journal Science has revealed that a plant hormone once believed to promote flower formation in annual plants also plays a role in inhibiting flowers from forming. The dual role of this hormone, gibberellin, could be exploited to produce higher-yielding crop plants.
The study was led by Nobutoshi Yamaguchi and Doris Wagner of the School of Arts and Sciences' Department of Biology. Wagner is professor and graduate chair, and Yamaguchi is a postdoctoral researcher. Department co-authors included Cara M. Winter, Miin-Feng Wu and Ayako Yamaguichi. The Penn team collaborated with Yuri Kanno and Mitsunori Seo of RIKEN Center for Sustainable Resource Science in Japan.
Plant scientists used to think that short-lived plants, annuals or bi-annuals, use a different strategy from long-lived plants, perennials, to regulate flower production.
"Anecdotal evidence was that the hormone gibberellin promoted the switch to flower formation in short-lived plants, along with other cues such as temperature, season and photoperiod," Wagner said. "But in the long-lived plants, like in fruit trees, people have known that if you sprayed them with the hormone it inhibited flower production. So it was a big puzzle: why would the same hormone do one thing in short-lived plants and another in long-lived plants?"
To address this paradox, the Penn team began by looking for new genes important to the flower-forming process. Specifically, they performed a genome-wide search of the plant species Arabidopsis thaliana to find direct targets of the protein LEAFY, which is known to promote flower formation.
One gene that turned up was called ELA1, which produces a c
|Contact: Katherine Unger Baillie|
University of Pennsylvania