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Gene blocking lettuce germination also regulates flowering time - Discovery could be crucial for adapting to climate change
Descubren que el gen que regula la germinación de las lechugas también se encarga de su floración 


Davis, California, USA
March 28, 2016

Two men in greenhouse examine flowering lettuce plant.Kent Bradford, left, and Alfred Huo, seen here with a flowering lettuce plant, found that lettuce could be prevented from flowering by increasing the expression of a specific microRNA in the plants. The high levels of this microRNA prevent the plant from transitioning to adulthood and flowering, and the plant continues to make numerous baby leaves rather than forming a compact head of lettuce. (Gregory Urquiaga/UC Davis)

  • Gene functions by acting on certain microRNAs
  • Process helps adapt timing of seed dormancy and flowering to environmental conditions
  • Findings important for $1.9 billion U.S. lettuce industry

Like most annuals, lettuce plants live out their lives in quiet, three-act dramas that follow the seasons. Seed dormancy gives way to germination; the young plant emerges and grows; and finally in the climax of flowering, a new generation of seeds is produced. It’s remarkably predictable, but the genetics that coordinates these changes with environmental cues has not been well understood.

In a recent study of lettuce and the model plant Arabidopsis, researchers at the UC Davis Seed Biotechnology Center and in China show for the first time that a gene known to direct the depth of seed dormancy and the timing of germination also influences flowering. The study further suggests that the gene does this by influencing production of certain microRNAs — tiny snippets of genetic material that govern transition from one phase of the plant’s life cycle to another.

The findings, which have important implications for the $1.9 billion annual U.S. lettuce crop, will be reported during the week of March 28 in the Proceedings of the National Academy of Sciences.

“It appears that the ‘Delay of Germination 1,’ or DOG1, gene is an environmental sensor, detecting environmental changes and enabling the plant to not only keep the seed dormant but to also delay flowering,” said study co-author Kent Bradford, a plant scientist and director of the Seed Biotechnology Center.

“This gene could be a particularly valuable tool as climate change shifts our growing seasons and we are forced to develop plants that can adapt to those environmental changes,” Bradford said.

Germination and flowering

Annual flowering plants match their life cycles­ — especially seed germination and flowering — to the appropriate season. If a flowering plant germinates too early, the seedling might appear before temperatures are warm enough for the plant to survive.

Such coordination of life cycles and environmental conditions is equally important for cultivated crops. An entire lettuce crop can be lost if the plants respond to early warm temperatures and “bolt,” producing flowers and seeds before marketable heads of lettuce have formed.

In the new study, the researchers found that suppressing the DOG1 gene in lettuce or Arabidopsis decreased the levels of one microRNA and increased levels of another. As a result, seeds germinated at higher temperatures, and the plants flowered earlier than normal.

“This provides evidence of a molecular genetic mechanism that is at work, coordinating adaptation of seed dormancy and flowering traits in the plants to accommodate environmental conditions,” said study co-author Heqiang “Alfred” Huo, a postdoctoral researcher in the Bradford lab.

“Our results also suggest that the period between seed dormancy and seed germination is a distinct phase in the plant’s lifecycle and that this phase appears to be influenced by the same microRNA systems that govern the plant’s maturation and flowering stages,” Huo said.

Collaborators and funding

Collaborating with Bradford and Huo was Shouhui Wei of the Chinese Academy of Agricultural Sciences in Beijing.

Funding for the study was provided by the U.S. Department of Agriculture competitive grants program and Rijk Zwaan seed company, headquartered in the Netherlands.


Source: Fundacion Antama

Descubren que el gen que regula la germinación de las lechugas también se encarga de su floración 

Un reciente estudio de la lechuga y la planta modelo Arabidopsis ha descubierto que el gen que regula su germinación también se encarga de la floración. El estudio, llevado a cabo por investigadores del Centro de Semillas Biotecnológicas de la Universidad de California (Estados Unidos), ha demostrado por primera vez que el gen conocido por determinar el momento de germinación de las semillas también influye en la floración. El estudio sugiera además que el gen tiene esta doble función al influir en al producción de ciertos microARNs, material genético que rige la transición de una fase del ciclo de vida de una planta a otra.

Kent Bradfor, científico co-autor del estudio y director del Centro de Semillas Biotecnológicas de la Universidad de California, explica que el ‘Retardo de germinación 1’, o gen DOG1, es un sensor capaz de detectar los cambios ambientales y que permite a la planta no sólo mantener la semilla latente, sino también retrasar la floración. Los investigadores encontraron que la supresión del gen DOG1 disminuye los niveles de un microARN y aumenta los niveles de otro. El resultado es la germinación de las semillas a temperaturas más altas y una floración temprana.

“Nuestros resultados también sugieren que el periodo entre latencia de las semillas y la germinación de las semillas es una fase distinta del ciclo de vida de la planta, y que esta fase parece estar influenciada por los mismos sistemas de microARN que controlan las etapas de maduración y floración de la planta”, explica el co-autor del estudio, Heqiang Alfred Huo.



More news from:
    . Rijk Zwaan BV
    . University of California, Davis


Website: http://www.rijkzwaan.nl

Published: March 28, 2016

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