Tweaked plants grow less but handle drought

Tweaked plants grow less but handle drought.
A group of proteins called WRKYs (pronounced ‘workies’) govern both stress response and growth in plants, report researchers.
This makes the proteins of particular interest to plant breeders and crop growers eager for varieties that will withstand dry conditions.
“They are important regulators for the balance of drought response and growth,” says Yanhai Yin, a professor of genetics, development, and cell biology at Iowa State University.
“They are very promising targets for plant breeding.” The paper describes how researchers in Yin’s lab managed to cross Arabidopsis plants in such a manner as to eliminate, or “knock out,” three different WRKYs genes, named for the several critical amino acids of which they’re composed.
Arabidopsis is a small flowering plant often used as a model in experiments.
Much of Yin’s research has centered on a plant protein known as BES1, an important switch in plant genomes regulated by a plant steroid called brassinosteroid that influences thousands of other genes.
Yin says WRKYs and BES1 work together to promote plant growth under normal conditions.
Previous studies have shown that WRKYs also help to govern bacterial response in plants as well.
Yin says his future studies will tease out how growth, drought tolerance, and bacterial response interact with one another.

Tardigrades use unique protein to protect themselves from desiccation

Tardigrades use unique protein to protect themselves from desiccation.
"In addition, the proteins that these genes encode can be used to protect other biological material — like bacteria, yeast, and certain enzymes — from desiccation."
But biochemical studies of tardigrades have found trehelose at low levels or not at all, and sequencing has not revealed the gene for the enzyme required to make this sugar.
The researchers identified genes that were upregulated and expressed at high levels when the animals began to dry out.
The proteins that these genes encode, the TDPs, are in a class of proteins called intrinsically disordered proteins (IDPs).
After they found the TDP genes expressed at high levels during the drying-out period in one species of tardigrade, the team looked at two other species and found the same genes.
"We think it can do this because it has so many of these proteins around already and doesn’t need time to make them," Boothby says.
To verify that these TDPs were what gave tardigrades their unique abilities, the researchers put the genes encoding them into yeast and bacteria, and confirmed that the TDPs protected these other organisms.
Trehelose helps other organisms to survive drying out by forming glass-like solids when they dry, rather than crystals.
These real-world applications are one of the things that led me to study tardigrades."

Overlooked plants defy drought

Overlooked plants defy drought.
A feature thought to make plants sensitive to drought could actually hold the key to them coping with it better, according to new findings published in eLife.
The new research suggests breeders should explore them for "stay green" traits.
"When breeders are looking for plants able to withstand drought, they discount those resistant to ABA, but our findings show that a subset of ABA-resistant plants may be a great source of drought-tolerant germplasm," says Professor Kathryn Barton from the Carnegie Institution for Science in California.
Drought and ABA trigger several water conserving strategies in the plant: pores on the leaf close to prevent evaporation, growth is slowed and some leaves yellow and fall from the plant.
The new research identifies a protein as the agent that retards growth and causes leaves to yellow.
Un-watered plants without the crucial ABIG1 protein retain double the number of green leaves, are able to remain upright and retain a healthier root system.
Barton and colleagues hypothesize that reducing the amount of ABIG1 in the plant increases the threshold at which the plant triggers drastic water conserving measures.
Raising this threshold may be one way to breed plants that remain green and growing during short-term drought episodes.
Plants that retain their leaves are able to continue to provide nutrition from the environment to the parts of the plants that we harvest, for example to the seeds we use for food.