A Cornell University research highlights a success in the attempt to boost photosynthesis in certain crops, a step toward adapting plants to rapid climate change and raising yields to feed the world's estimated 9 billion people by 2050.
The study, titled "Improving Rubisco Efficiency by Resurrecting Its Ancestors in the Family Solanaceae," was published on April 15 in Science Advances.
Maureen Hanson, the Liberty Hyde Bailey Professor of Plant Molecular Biology at the College of Agriculture and Life Sciences, is the senior author.
Myat Lin, the first author, is a postdoctoral research associate in Hanson's group.
Ancient rubisco enzyme
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The researchers devised a computer method for predicting favorable gene sequences that produce Rubisco, a critical plant enzyme for photosynthesis.
The approach enabled the scientists to find interesting candidate enzymes that may be incorporated into current crops, hence increasing photosynthesis efficiency and agricultural yields.
Earth's carbon dioxide (CO2) levels were greater than they are now and Rubisco enzymes in plants were suited to those levels.
Early discoveries indicate promise for producing quicker, more efficient Rubisco enzymes to insert into crops and help them adapt to hot, dry future circumstances by reviving old Rubisco.
Modern developments have increased heat-trapping CO2 gas concentrations in Earth's atmosphere, as per Sciencedaily.
"We were able to find projected ancestral enzymes that indeed have superior capabilities compared to current-day enzymes," Hanson said in a Cornell College of Agriculture and Life Sciences press release (CALS).
Myat Lin, the first author, used Solanaceae plants to rebuild a Rubisco phylogeny, the tree-like graphic demonstrated the plants' evolutionary relatedness.
"By obtaining a large number of Rubisco genetic sequences from contemporary plants, a phylogenetic tree could be formed to determine which Rubiscos likely existed 20 to 30 million years ago," Hanson added, as per Seedworld.
Read more: E. Coli Can Improve Photosynthesis With the Use of the Rubisco Enzyme
Gene editing of rubisco sequence
The benefit of detecting putative old Rubisco sequences is that carbon dioxide levels in the atmosphere were probably as high as 500 to 800 parts per million (ppm) 25 million to 50 million years ago.
Heat-trapping CO2 levels are now growing significantly as a result of several human activities, with current values about 420 ppm, after remaining relatively steady under 300 ppm for hundreds of millennia until the 1950s.
Lin, Hanson, and colleagues then employed an experimental method established in Hanson's group for tobacco and detailed in a Nature Plants study published in 2020, which utilizes E. coli bacterium to evaluate the efficiency of several Rubisco formulations in a single day. Similar experiments in plants take months to validate.
The researchers discovered that ancient Rubisco enzymes anticipated from modern-day Solanaceae plants showed considerable potential in terms of efficiency.
The next step is to use CRISPR, a sort of gene-editing technique, to replace the genes for the present Rubisco enzyme in tobacco with these ancestral sequences, and then see how it impacts biomass production, according to Hanson.
"We absolutely expect that our trials will prove that by adjusting Rubisco to current circumstances, we will be able to produce plants with higher yields."
If their strategy is effective, these efficient Rubisco sequences might be applied to crops like tomatoes, as well as those from other plant families like soybeans and rice.
