Plant breeding: Using ‘invisible’ chromosomes to pass on packages of positive traits

The ideal crop plant is tasty and high-yielding while also being resistant to diseases and pests. But if the relevant genes are far apart on a chromosome, some of these positive traits can be lost during breeding.

To ensure that positive traits can be passed on together, researchers at Karlsruhe Institute of Technology (KIT) have used CRISPR/Cas molecular scissors to invert and thus genetically deactivate nine-tenths of a chromosome.

The traits coded for on this part of the chromosome become “invisible” for genetic exchange and can thus be passed on unchanged. The researchers have reported on their findings in Nature Plants.

Targeted editing, insertion or suppression of genes in plants is possible with CRISPR/Cas molecular scissors. (CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats.) This method can be used to make plants more resistant to pests, diseases or environmental influences.

“In recent years, we were able for the first time to use CRISPR/Cas not only to edit genes but also to change the structure of chromosomes,” says Professor Holger Puchta, who for 30 years has been researching applications for gene scissors with his team at KIT’s Botanical Institute.

“Genes are linearly arranged along chromosomes. By changing their sequence, we were able to show how desired traits in plants can be separated from undesired ones.”

‘Dream’ discovery could sow crops better equipped to weather the climate change storm

Scientists from The Australian National University (ANU) and James Cook University (JCU) have identified an “exquisite” natural mechanism that helps plants limit their water loss with little effect on carbon dioxide (CO2) intake – an essential process for photosynthesis, plant growth and crop yield.

The discovery, led by Dr Chin Wong from ANU, is expected to help agricultural scientists and plant breeders develop more water-efficient crops.

Study co-author Dr Diego Marquez from ANU said the findings will have significant implications for the agricultural industry and could lead to more resilient crops that are capable of withstanding extreme weather events, including drought.

“Plants continuously lose water through pores in the ‘skin’ of their leaves. These same pores allow CO2 to enter the leaves and are critical to their survival,” Dr Marquez said. 

“For every unit of CO2 gained, plants typically lose hundreds of units of water. This is why plants require a lot of water in order to grow and survive.

“The mechanism we have demonstrated is activated when the environment is dry, such as on a hot summer day, to allow the plant to reduce water loss with little effect on CO2 uptake.”

How stressed plants produce their own aspirin – discovery could protect plants from climate change

Plants protect themselves from environmental hazards like insects, drought and heat by producing salicylic acid, also known as aspirin. A new understanding of this process may help plants survive increasing stress caused by climate change.

UC Riverside scientists recently published a seminal paper in the journal Science Advances reporting how plants regulate the production of salicylic acid.

The researchers studied a model plant called Arabidopsis, but they hope to apply their understanding of stress responses in the cells of this plant to many other kinds of plants, including those grown for food.

“We’d like to be able to use the gained knowledge to improve crop resistance,” said Jin-Zheng Wang, UCR plant geneticist and co-first author on the new study. “That will be crucial for the food supply in our increasingly hot, bright world.”

Environmental stresses result in the formation of reactive oxygen species or ROS in all living organisms. Without sunscreen on a sunny day, human skin produces ROS, which causes freckles and burns. High levels of ROS in plants are lethal.

As with many substances, the poison is in the amount. At low levels, ROS have an important function in plant cells.

“At non-lethal levels, ROS are like an emergency call to action, enabling the production of protective hormones such as salicylic acid,” Wang said. “ROS are a double-edged sword.”

The research team discovered that heat, unabated sunshine, or drought cause the sugar-making apparatus in plant cells to generate an initial alarm molecule known as MEcPP.

Going forward, the researchers want to learn more about MEcPP, which is also produced in organisms such as bacteria and malaria parasites. Accumulation of MEcPP in plants triggers the production of salicylic acid, which in turn begins a chain of protective actions in the cells.

“It’s like plants use a painkiller for aches and pains, just like we do,” said Wilhelmina van de Ven, UCR plant biologist and co-first study author.

The acid protects plants’ chloroplasts, which are the site of photosynthesis, a process of using light to convert water and carbon dioxide into sugars for energy.

“Because salicylic acid helps plants withstand stresses becoming more prevalent with climate change, being able to increase plants’ ability to produce it represents a step forward in challenging the impacts of climate change on everyday life,” said Katayoon Dehesh, senior paper author and UCR distinguished professor of molecular biochemistry.

“Those impacts go beyond our food. Plants clean our air by sequestering carbon dioxide, offer us shade, and provide habitat for numerous animals. The benefits of boosting their survival are exponential,” she said.

Journal Reference

1. Jin-Zheng Wang, Wilhelmina van de Ven, Yanmei Xiao, Xiang He, Haiyan Ke, Panyu Yang, Katayoon Dehesh. Reciprocity between a retrograde signal and a putative metalloprotease reconfigures plastidial metabolic and structural states. Science Advances, 2022; 8 (22) DOI: 10.1126/sciadv.abo0724

Source:  ScienceDaily 

Infected pines starve and disease-causing fungi thrive as the globe warms

The high heat and low water conditions produced by global warming weaken pine trees’ resistance to disease by hindering their ability to mount an effective defense at the same time that pathogenic fungi in their tissues become more aggressive, new research suggests.

The study is the first to simultaneously examine metabolic gene expression in both host trees and the pathogens attacking them under normal and climate-change conditions. The findings help explain the mechanisms behind what has become a well-known fact: The warming world makes trees more susceptible to disease.

The study was conducted on Austrian pines, which are native to southern Europe and used ornamentally in the United States. Researchers tested climate change conditions’ effects on the trees after infection by two related fungi that have killed large swaths of these pines over time.

New research centre signals step change for plant production industry

Lincoln University has formalised a Memorandum of Understanding with the board of New Zealand Plant Producers Inc (NZPPI).

The agreement will result in the launch of a centre to provide education, research and extension capability and capacity-building programmes for the plant production industry in New Zealand.

The new research centre, based at Lincoln University, will comprise research and education facilities and equipment, access to science capability and knowledge, a central administrative function, as well as physical premises for hosting conferences, workshops and other collaborative gatherings of industry leaders.

The new centre will be at the hub of a more open innovation and knowledge network that will be positioned to rapidly initiate and accelerate the transfer and adoption of new science and technology throughout all regions of the country.

Historically, New Zealand’s research model in horticulture and forestry has been based around the long-term national priorities of biosecurity, the environment and growth of the export sector.

Climate change: researchers are bolstering plant immunity against the heat

When heat waves hit, they take a toll on the plants we depend on for food because certain plant defenses don’t work as well when temperatures get too high.  This leaves them more susceptible to attacks from pathogens and insect pests.

Scientists now say they have identified a specific protein in plant cells that explains why immunity falters as temperatures rise.  They have also found a way to reverse the loss and bolster plant defenses against the heat.

The findings, appearing June 29 in the journal Nature, were found in a spindly plant with white flowers called Arabidopsis thaliana that is the “lab rat” of plant research.

Artificial photosynthesis can produce food without sunshine

Scientists have found a way to bypass the need for biological photosynthesis altogether and create food independent of sunlight by using artificial photosynthesis. The technology uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate. Food-producing organisms then consume acetate in the dark to grow.

The hybrid organic-inorganic system could increase the conversion efficiency of sunlight into food, up to 18 times more efficient for some foods.

Photosynthesis has evolved in plants for millions of years to turn water, carbon dioxide, and the energy from sunlight into plant biomass and the foods we eat. This process, however, is very inefficient, with only about 1% of the energy found in sunlight ending up in the plant.

Scientists at UC Riverside and the University of Delaware have found a way to bypass the need for biological photosynthesis altogether and create food independent of sunlight by using artificial photosynthesis.

Hybrid plant varieties – how they could tackle the challenges of food security and climate change

A recent article posted on Phys.org notes that hybrid agricultural and horticultural crops can play an important role in supporting global food security. They produce higher yields and are often more resistant than non-hybrid varieties to diseases and climate stress.

But no hybrid varieties are available for many crops.

Referencing an article published in Nature Plants, thephys.org article looks into the reasons for this.  It says:

Maize is a globally very important crop, and the use of hybrid varieties is routine. The first type was introduced as far back as 1930. But that hasn’t happened for other major crops such as wheat and cassava. Now, for the first time, a comprehensive study has been done of all the factors that determine whether commercial plant breeders can come up with a hybrid variety. Sometimes there are biological challenges. Often, economic factors come into play.

It’s a uniquely comprehensive survey, published in the journal Nature Plants. The authors of the article are associated with hybrid potato breeding company Solynta and Wageningen University & Research. The lead author is Emily ter Steeg, a Ph.D. candidate in development economics.

Gene-edited tomatoes could be a new source of vitamin D

Tomatoes gene-edited to produce vitamin D, the sunshine vitamin, could be a simple and sustainable innovation to address a global health problem.

Researchers used gene editing to turn off a specific molecule in the plant’s genome which increased provitamin D3 in both the fruit and leaves of tomato plants. It was then converted to vitamin D3 through exposure to UVB light.

Vitamin D is created in our bodies after skin’s exposure to UVB light, but the major source is food. This new biofortified crop could help millions of people with vitamin D insufficiency, a growing issue linked to higher risk of cancer, dementia, and many leading causes of mortality. Studies have also shown that vitamin D insufficiency is linked to increased severity of infection by Covid-19.

Higher wheat yields and protein content on the horizon

A team of international researchers has discovered a way to produce higher-quality wheat.

The scientists from the University of Adelaide and the UK’s John Innes Centre have identified a genetic driver that improves yield traits in wheat, which unexpectedly can also lead to increasing protein content by up to 25 per cent.

“Little is known about the mechanism behind drivers of yields and protein content in wheat production,” said the University of Adelaide’s Dr Scott Boden, School of Agriculture, Food and Wine who led the research.

“Discovering a gene that controls these two factors has the potential to help generate new wheat varieties that produce higher quality grain.

“As wheat accounts for nearly 20 per cent of protein consumed worldwide, the impact of this research can significantly benefit society by providing grains with a higher protein content, which could therefore help produce more nutritious food, such as bread and breakfast cereals.”