Stanford Scientists Unlock Mysteries of Plant Growth and Health

The breakthrough will aid in the development of heat-tolerant crops and the manufacture of algal biofuels.

Plants, like all other living things, use DNA to pass on their properties. Animal genetics normally focuses on parentage and lineage, but this may be difficult in plant genetics since plants, unlike most animals, can be self-fertile.

Many plants have special genetic abilities that facilitate speciation, such as being polyploidy tolerant. Plants are unique in that they can produce energy-dense carbohydrates through photosynthesis, which is carried out by chloroplasts. Chloroplasts contain their own DNA, allowing them to act as a reservoir for genes and genetic variation, as well as adding a depth of genetic complexity not observed in mammals. Plant genetic research, despite its difficulties, has enormous economic ramifications. Many crops may be genetically engineered to boost production and nutritional value while also gaining resistance to pests, herbicides, and diseases.

Genes hold all of an organism's instructions for survival, development, and reproduction. However, there is a big difference between discovering a gene and knowing what it does. Many genes have inexplicable instructions, and scientists don't know what they do. UC Riverside, Princeton University, and Stanford University recently published a study that revealed the activities of hundreds of genes in algae, some of which are also found in plants. The innovation will help scientists develop climate-resistant agricultural crop kinds and genetically alter algae for biofuel generation.

“Plant and algae genetics are understudied. These organisms make the foods, fuels, materials, and medicines that modern society relies on, but we have a poor understanding of how they work, which makes engineering them a difficult task,” said corresponding author Robert Jinkerson, an associate professor of chemical and environmental engineering at UC Riverside. “A common way to learn more about biology is to mutate genes and then see how that affects the organism. By breaking the biology we can see how it works.” 

Using algal mutants and automated technologies, the researchers ran tests that generated millions of data points. By examining these datasets, the researchers were able to discover the functional role of hundreds of poorly described genes and discover numerous novel roles for previously recognized genes. Photosynthesis, DNA damage response, heat stress response, toxic chemical reaction, and algal predator response are all regulated by these genes.

Several of the genes found in algae have plant equivalents with similar functions, indicating that the algal data can aid scientists in understanding how those genes operate in plants.

High-throughput technologies, which automate the analysis of tens of thousands of mutants fast, are commonly employed in model systems like yeast and bacteria to investigate gene function on a genome-wide scale. This is a more effective and time-saving method than examining each gene separately. Crop plants, on the other hand, do not respond well to high-throughput approaches due to their bigger size and the difficulties of evaluating thousands of plants.

As a result, the researchers employed a high-throughput robot to create over 65,000 mutants of Chlamydomonas reinhardtii, a single-celled green algae closely related to plants that is easy to genetically modify. They used 121 different treatments on the mutants, resulting in a dataset of 16.8 million data points. Each mutant had a unique DNA barcode that the scientists could read to evaluate how it fared in various environmental stress situations.

Hundreds of genes were revealed to have novel roles by the team. They discovered, for example, that a gene common in multicellular creatures aids in the repair of damaged DNA. When another 38 genes were disrupted, it resulted in issues utilising light energy, demonstrating that these genes were involved in photosynthesis.

Another set of genes aided the algae in processing carbon dioxide, the second and most important phase in photosynthesis. Other clusters harmed the algae's microscopic hairs, or cilia, which help them swim. This finding might lead to a better understanding of some human lung and esophageal malignancies, which may be caused in part by cilia motility defects.

Toxins that impair cytoskeleton expansion were protected by a newly found gene cluster. These genes are also found in plants, and the discovery might aid scientists in developing plants that can thrive even in polluted environments.

Many of the gene functions reported in algae have been found in plants as well. This knowledge may be used to modify plants to be more resistant to heat or cold stress, temperature stress, or to increase photosynthesis, all of which will become more relevant as climate change threatens the world's food supply.

A deeper knowledge of algal genetics will help enhance engineering tactics for increasing the number of items they can generate, such as biofuels.

“The data and knowledge generated in this study is already being leveraged to engineer algae to make more biofuels and to improve environmental stress tolerance in crops,” Jinkerson added.