New Light on Seed Germination Genetics

Scientists have identified a key gene that helps seeds decide whether to germinate.

The study was conducted on Arabidopsis, a very close relative of oilseed rape.

The MFT gene stops seeds germinating in the dark or under shady conditions, where their chances of survival would be poor, according to new research from the University of York.

The study, conducted on Arabidopsis, a very close relative of oilseed rape, increases our understanding of one of the most important stages in the life cycle of a plant and may help to improve the seed quality of agricultural crops in the future.

Signals

Scientists have known for some time that two plant hormones play an important role in regulating if and when a seed will germinate - “Abscissic Acid” or ABA blocks germination and “Gibberelins” or GA promotes it.

However, in a breakthrough in our understanding of the mechanism by which these hormones control germination in response to light quality, the researchers have discovered that MFT is the key component that integrates and interprets signals coming from both ABA and GA.

The MFT gene is regulated by light quality and receives signals from both ABA and GA. In dark or shady conditions, it then directs the production of the MFT protein, which regulates germination by switching on a block of genes that prevent growth and switching off another block of genes that promote growth.

Sophisticated mechanism

This prevents a plant from germinating under the wrong conditions such as when there is not enough light to grow.

Professor Ian Graham, corresponding author, from the Centre for Novel Agricultural Products in the Department of Biology at the University of York, said: “This is another great example of how plants have evolved very sophisticated molecular mechanisms to stay in tune with their environment. This allows seeds to survive in the soil for many years so that when the time is right, such as when a tree falls in a forest or soil is turned over, seeds can suddenly spring into action.”

For many plant species the ability of a seed to sense the quality of light can inform it if it is located in direct sunlight, under a canopy of other plants that only allow a certain quality of light to pass through or in the dark, which is often the case when seeds are buried in the soil.

Survival

In wild plant species the ability for seeds to remain dormant even under conditions that would allow them to germinate is important for survival. For crops species, eliminating this dormancy is one of the first traits that has to be dealt with in a plant breeding programme.

Lead author of the work, Dr Fabian Vaistij, from the Department of Biology at the University of York added: “Understanding the molecular genetic basis of how seed germination is controlled will provide new tools to improve seed quality and seedling vigour in developing new crops for the future.” 

This work provides some ideas about how light interacts with seeds and germination.  Especially where species are known to respond to light during germination.  Zoysia turf grass is one of the species that does require light to germinate - if buried, even at shallow depth, germination and subsequent establishment is greatly impaired.

[ adapted from University of York press release 7 August 2018]

Mosquito Control with Sterile Insects

The world's most dangerous animal isn't a lion, shark, snake or croc: it's the menacing mosquito. 

While many mosquitos are harmless to humans and ecologically important, three groups of mozzies, the Aedes, Anopheles and Culex, are found almost all over the world and are responsible for around 17 per cent of infectious disease transmissions globally. 

In a landmark trial working with international partners, CSIRO were able to suppress the invasive and disease spreading Aedes aegypti mosquito by 80 per cent along the Cassowary Coast, Queensland. 

Millions of non-biting male Aedes aegypti mosquitoes were reared, sterilised using a natural bacteria and re-released into the area.

Click through on the link to read the story - Australian science at work - for good! Read more by clicking through below.

Very sharp, smart science!

Our infertile mozzies are now wiping out the invasive irritants.

Click here

Innovative Methodology For Multiple Gene Insertion Into Plants - Easier Plant Improvement

Agricultural Research Service (ARS) scientists in Albany, California, have found a way to streamline the process that scientists use to insert multiple genes into a crop plant, developing a reliable method that will make it easier to breed a variety of crops with vastly improved traits.

The technology is expected to speed up the process for developing new varieties of potatoes, rice, citrus and other crops that are better equipped to tolerate heat and drought, produce higher yields and resist a myriad of diseases and pests. Crops with greater resistance to pathogens and insects could greatly reduce pesticide use and prevent billions of dollars in crop losses.

“Making genetic improvements that were difficult or impossible before will be much easier because we can now insert not just one or two genes, but multiple genes, into a plant in a way that will lead to predictable outcomes,” said Roger Thilmony, an ARS molecular biologist in Albany.

A paper describing the achievement by Thilmony, James Thomson, an ARS geneticist in Albany, and Ray Collier, a former ARS postdoctoral researcher, was published recently in the August issue of The Plant Journal.

The GAANTRY gene stacking technology will be freely available to anyone interested, and a commercial firm in the US is planning to use it to introduce multiple genes into potatoes to make them more resistant to late blight, which is caused by a fungus-like organism. Late blight can destroy entire fields and force some farmers to spray fungicides up to 15 times a year.

“We have struggled to put multiple late blight resistance genes into potatoes for years. They are very long, complex genes, and with existing technologies it’s been extremely difficult. But the GAANTRY technology will help us tremendously,” said Craig Richael, a director of research and development for J.R. Simplot Co., an Idaho-based company that produces French fries, frozen vegetables, fertilizer, turf grass seed and other products.

Scientists over the years have modified the genetics of soybeans, corn, canola and other crop plants to develop varieties that tolerate specific herbicides and resist insect pests. But those traits were controlled by one or two genes, and in most crop plants, important traits such as cold and drought tolerance, yield and seed production are almost always controlled by multiple genes. Inserting more than two or three genes into the same site on a plant chromosome has been notoriously difficult.

The researchers’ unique platform stabilizes large “stacks” of DNA needed for conferring key traits, allowing researchers to insert suites of genes “so precisely that no unintended DNA is added or lost during the process,” says Thomson.

“Before this, assembling 10 genes to insert into a new line would be difficult or impossible, but this technology basically stabilizes the stack and makes for results that are more stable and much easier to predict,” Thilmony said.

Read the report in The Plant Journal.

This technology offers some very smart options for plant improvement, and is potentially likely to be assessed similarly as the CRSPR system whereby derived plant lines are not assessed as GM plants, easing regulatory approvals. 

The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. 

Each dollar invested in agricultural research through the ARS results in $20 of economic impact.

That is a very good return on the investment.   I wonder if those returns are achieved in Australian institutions?

[ modified from publicly available press release of ARS ]