Flower Power Genetics: The Hidden Link Between Genes and Flower Formation Revealed

A team of researchers from the University of Massachusetts at Amherst recently announced that they have discovered the genetic links governing flower formation. The reveal solves a long-standing mystery – how are there so many different types of flowers in the world? – and sheds a bright light on a dark corner of evolution. The research also demonstrates the power of a technique called “direct genetics” to unlock the mysteries of nature.

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Panicles of mutant maize in which programmed cell death has been suppressed. Credit: UMass Amherst

“The flowers are amazing,” says Madelaine Bartlett, a UMass Amherst biology professor and lead author of the paper, recently published in the Proceedings of the National Academy of Sciences. “They’re all built with the same components, and yet we have incredible diversity, from corncobs to orchids. We want to know how the same few pieces end up creating such different shapes. »

It has long been known that a process called “programmed cell death” is partly responsible for the morphological diversity of flowers. Programmed cell death is a genetic mechanism that voluntarily eliminates certain cells – which is why humans don’t have webbed fingers – and it’s at work in flower carpels, or the seed-bearing structures at the heart of the flower. Huge floral variety is governed by which parts of flower growth are suppressed, and one gene in particular, known as GRASSY TILLERS1 (GT1), influences suppression of carpel growth in maize. But it’s not the only gene regulating the process, and so far no one has been able to identify any others that interact with GT1 to suppress maize carpels.

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Madelaine Bartlett in the Cornfield
Madelaine Bartlett in the cornfield. Credit: UMass Amherst

Focusing on cornflowers – think of a corn cob or a branching tassel at the top of a corn plant – the team, led by Harry Klein, who completed this research as part of his PhD. in plant biology at UMass Amherst and now at the Dana-Farber Cancer Institute, designed a novel experiment to identify other genes regulating carpel suppression with GT1. At the heart of their experiment is a technique known as “direct genetics”, which is a way of working backwards from a known flower formation, or phenotype – in this case, a mutated corn flower caused by a genetic alteration in cell death. process – to the specific mutation causing this mutant formation.

According to Bartlett, finding the specific genes that govern any individual trait is like “finding a needle in a haystack,” so Klein performed a series of genomic analyzes with the complex maize genome. The result was that Klein and his co-authors discovered that another gene, RAMOSA3 (RA3), also plays a vital role in programmed carpel cell death in maize. This surprised Klein and his colleagues, as RA3 was previously thought to play only a role in how plants branch. But it turns out that RA3 is pleiotropic, meaning it influences more than one trait.

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Harry Klein in the cornfield
Harry Klein in the cornfield. Credit: UMass Amherst

Not only does the team’s discovery tell us more about the evolution of life on earth, it has implications for the applied science of plant breeding, since flowers give humans everything from apples to nuts. by the ear of corn which has become summer time. staple in much of the United States.

This research was supported by the National Science Foundation, USDA National Institute of Food and Agriculture, University of Massachusetts, Max Planck Society, Lotta M. Crabtree Foundation, and Institute for Applied Life Sciences (IALS ) from UMass Amherst, which combines knowledge and the interdisciplinary expertise of 29 departments on the UMass Amherst campus to translate fundamental research into innovations that benefit human health and well-being.

Harry D. Gonzalez