Many genetic and breeding studies have shown that point mutations and indels (insertions and deletions) can alter elite traits in crop plants. Although nuclease-initiated homology-directed repair (HDR) can generate such changes, it is limited by its low efficiency. Base editors are robust tools for creating base transitions, but not transversions, insertions or deletions. Thus, there is a pressing need for new genome engineering approaches in plants.
A new computer application (app) could speed the search for genes that underpin important crop traits, like high yield, seed quality and resistance to pests, disease or adverse environmental conditions.
The researchers found that farms with diverse crops planted together provide more secure, stable habitats for wildlife and are more resilient to climate change than the single-crop standard that dominates today’s agriculture industry.
Few technologies have made as big a splash in recent years as CRISPR/Cas9, and rightfully so. CRISPR/Cas9, or clustered regularly interspaced palindromic repeats (CRISPR) and associated genes, is a bacterial gene editing toolbox that allows researchers to edit genomic sequences much more precisely and efficiently than previously possible, opening up doors to new ways of doing research. As with many new biotechnologies, the application of CRISPR in biology began with genetic model organisms such as Arabidopsis thaliana. In recent research authors review the prospects for expanding the use of CRISPR for research beyond genetic model plant species.
Plants can’t self-isolate during a disease outbreak, but they can get help from a friend — beneficial soil microbes help plants ward off a wide range of diseases. Now, scientists have uncovered a major part of the process in which beneficial fungi help corn plants defend against pathogens.
For plants, sunlight can be a double-edged sword. They need it to drive photosynthesis, the process that allows them to store solar energy as sugar molecules, but too much sun can dehydrate and damage their leaves. A primary strategy that plants use to protect themselves from this kind of photodamage is to dissipate the extra light as heat. However, there has been much debate over the past several decades over how plants actually achieve this.
Cyanobacteria – colloquially also called blue-green algae – can produce oil from water and carbon dioxide with the help of light. This is shown by a recent study. The result is unexpected: Until now, it was believed that this ability was reserved for plants. It is possible that blue-green algae will now also become interesting as suppliers of feed or fuel, especially since they do not require arable land.
Introverts take heart: When cells, like some people, get too squished, they can go into defense mode, even shutting down photosynthesis.
In a study recently published, a team at CU Boulder took advantage of a new microscopic technique to follow the lives of individual bacteria as they grew and divided in complex colonies.
The researchers discovered something unexpected in the process: Whenever these single-celled organisms, a type of cyanobacteria or blue-green algae, got too smushed, they began to switch off the machinery that was essential for them to turn sunlight into sugar.
The tiny organisms, in other words, slowed down their growth in a big way, said Jeffrey Cameron, an assistant professor in the Department of Biochemistry and coauthor of the new research.
“If a cell is between a rock and a hard place, internally everything says, ‘Yes, I have nutrients. I want to grow,’” said Cameron, also of the Renewable and Sustainable Energy Institute (RASEI) at CU Boulder. “But there also has to be a feedback that says, ‘I need to turn off photosynthesis so I don’t expand and rupture.’”
The findings, which appear in Nature microbiology, provide a new window on this process that sustains most life on Earth—and, in particular, how organisms regulate photosynthesis when the going gets tough. Cameron hopes that his team’s results will also help scientists to develop custom-made microbes that could one day turn light into electricity or even construct living buildings.
As Cameron explains, it all began almost by accident.
He launched this research several years ago with a deceptively simple goal in mind: He and his colleagues wanted to track the behavior of individual cells within a bacterial colony throughout their entire lifecycle.
That was a difficult feat—for simple-looking organisms, cyanobacteria can form pretty complex structures.
“The cells on the outside of a colony are exposed to a lot of light, while those on the inside have low light exposure,” Cameron said. “Over time as they grow and accumulate more cells, they shade themselves.”
To be able to see every single cell in a growing colony, Cameron developed a method of culturing cyanobacteria so that they spread out like flat pancakes. When he started peering at these two-dimensional growths under a microscope, he noticed something odd: The more the colonies grew, and the more the bacteria inside began to squeeze together, the more they began to glow, or “fluoresce,” under a certain type of light.
The microbes, he explained, were emanating heat out to their environment, almost like a person perspiring on a packed city bus.
“I dropped everything and spent the next four years figuring out what was happening,” Cameron said.
The key, he and his colleagues discovered, was that the cells in a colony weren’t all glowing the same. The cyanobacteria on the inside of a colony, for example, fluoresced a lot more than those on the fringes. They also grew a lot slower, dividing in two at about half the rate as their exterior cousins.
Put differently, when cells get squished, they shine.
“When the cells become confined, and they can’t expand, they become highly fluorescent,” Cameron said.
So why were those interior cells perspiring so much?
To answer that question, you have to get to know the phycobilisome. This teeny, protein-based structure is the antenna of the cell. Many of these phycobilisomes sit inside cyanobacteria where they collect sunlight, then transport it to the reaction sites where that energy can be converted into glucose, or sugar.
Or that’s what usually happens. Cameron and his colleagues found that when their cyanobacteria became too confined, they started to shed their phycobilisomes.
“If the cyanobacteria got more light than they could use for photosynthesis, these antennae would literally pop off,” Cameron said.
The microbes couldn’t use all that energy, so to keep from getting glutted, they turned off photosynthesis.
The group’s results, he said, show just how dynamic single-celled organisms can be: They have a lot of tools for staying healthy in a dynamic social environment.
Understanding that social environment could also one day help scientists put photosynthesis to work—tapping sunlight to design more sustainable buildings or make other biology-based tools.
“We might be able to develop small-scale machines that are using light to perform computations or work,” Cameron said.
It’s a whole new way to think about catching some rays.
Other coauthors on the new study include CU Boulder researchers Kristin Moore, a former graduate student in RASEI; Sabina Altus, a graduate student in the Department of Applied Mathematics; Jian Wei Tay, an image analysis specialist in RASEI; Janet Meehl, a professional research assistant in RASEI; Evan Johnson, lab manager; and David Bortz, an associate professor of applied mathematics.
Read the paper: Nature microbiology
Article source: University of Colorado at Boulder
Author: Daniel Strain
Image credit: Kristin A. Moore and Jeffrey C. Cameron
For billions of years life on Earth was restricted to aquatic environments, the oceans, seas, rivers and lakes.
Then 450 million years ago the first plants colonised land, evolving in the process multiple types of beneficial relationships with microbes in the soil.
These relationships, known as symbioses, allow plants to access additional nutrients. The most intimate among them are intracellular symbioses that result in the accommodation of microbes inside plant cells. A study recently published describes the discovery of a common genetic basis for intracellular symbioses.
Researchers have created the world’s first framework, to better guide the management of terrestrial invasive species. By using a big data approach the researchers found a way to prioritise targets in the control of invasive species.
