At UC Davis, the Ronald lab is on a mission: use biotechnology to tackle food insecurity, especially when it comes to rice. One of the landmark successes of the Ronald lab is the development of rice resistant to flooding, as “[i]n India and Bangladesh alone, submergence destroys 4 million tons of rice each year, enough to feed 30 million people.” Rice is prolific and filling, and countless people rely on the crop to keep from starving, especially in regions subject to flooding. Losses due to submergence can devastate populations, and these events are expected to be exacerbated by climate change. Fortunately, these researchers had a plan.

Although most rice varieties will die after just three days underwater, a few varieties have been identified that can endure submergence for longer. One variety, flood-resistant 13A (FR13A), can tolerate two weeks of submergence, though its grain is undesirable and suffers from relatively low yields. 

Thanks to modern biotechnology, though, this unfortunate combination does not mark the end for flood-resistant rice. Researchers at the Ronald lab were able to identify the gene responsible for FR13A’s endurance to submergence, aptly named Sub1A. The general location of this gene had been discovered by other UC Davis researchers years prior, but attempts to selectively breed the gene into traditional varieties had been unsuccessful, as extraneous genes from FR13A lingered in hybrids. However, identifying the precise gene responsible for flood tolerance allowed researchers to genetically engineer another rice variety to contain Sub1A. This test confirmed Sub1A’s role; the GM strain significantly outperformed its traditional counterpart under flooded conditions. 

The potential of this trait is not to be understated; not only does flood tolerance prevent losses due to uncontrollable weather conditions, but flooding can be used intentionally by farmers to kill off weeds without harming their harvests. However, researchers knew GMO opposition could hinder the potential impacts of this incredible innovation. 

Instead of introducing Sub1A rice as a GMO, they used marker-assisted breeding, a technique that allows new rice varieties with the Sub1A gene to be considered non-GMO. Marker-assisted breeding is a type of selective breeding technique, but instead of crossing two varieties and hoping just one gene is transferred from FR13A, it uses molecular data to analyze the crossed seeds. FR13A was bred with Swarna, a rice variety known for its quality and high yields. First, researchers discarded the hybrids without the Sub1A region. Then, since nobody wants FR13A’s other genes to replace Swarna’s, they basically filtered all of its other genes out. They did this by finding the seeds with the most overlap with Swarna’s genome and backcrossed those with Swarna. This process was repeated until they achieved a strain identical to Swarna except for the Sub1A region, resulting in a flood-resistant Swarna strain without the GMO label.

In addition to Swarna, the Sub1A gene was introduced to other popular rice types, maintaining species diversity while protecting farmers’ yields. In a YouTube video published by the International Rice Research Institute (IRRI), one of these popular strains, IR64, was grown next to its counterpart with the Sub1A gene, under the same flooding conditions. While the traditional variety produced 1.4 tons of rice per hectare, the Sub1A version yielded 3.8 tons per hectare, a staggering 270% increase. According to the IRRI, Sub1A rice can save $700 in protected yields per hectare, something direly needed in Africa, where events of severe flooding are rising due to climbing global temperatures.

Fortunately, adoption of Sub1A rice by farmers is predicted to increase, especially in those with access to information about it. Rough estimates from a Cambridge University paper predict that new farmers implementing Sub1A rice would save an additional $109.56 million annually in Assam, Odisha, and West Bengal, adding to the 6 million global farmers already growing it in 2017. Estimates from this paper assert that if all farmers in the three Indian states are informed about Sub1A rice, the value of annual preserved yields would surpass $500 million.

The relatively rapid spread of Sub1A rice can be largely attributed to marker-assisted breeding. Though GMOs face many regulatory hurdles, including outright bans in many countries, marker-assisted breeding is much more accepted. By utilizing this method to create Sub1A varieties, the Ronald lab maximizes the number of people able to access this improved rice. However, this technique doesn’t work to replace every GMO. Marker-assisted breeding cannot be applied to GMOs like Golden Rice, because since cross-breeding is integral to the process, both organisms involved must be closely related. With two rice species, this is no problem, but Golden Rice contains transgenes from corn and a bacterium, which are not so easily bred with rice. For example, the Ronald lab has also modified rice varieties using CRISPR-Cas9 to amplify carotenoid production. The GM rice resulting from this project is subject to strict regulatory hurdles that would prevent farmers from growing and distributing it. Although Sub1A rice was able to broaden its reach through marker-assisted breeding, advocacy for GMOs must persist, as the misconceptions of their safety prevent innovations like Golden Rice from saving thousands of lives every year.

The time I’ve dreaded for the past two years has finally come: time to make decisions.

Last week, I was accepted to UC Davis with the Regent’s Scholarship I had only dreamed of receiving, along with additional financial aid from the university. Immediately, I searched for Davis labs researching plant genome editing, but was disappointed with how few results I found. When it comes to plants, it seems like UC Davis is less involved in gene editing when compared to institutions like UC Berkeley, which have a greater focus on the molecular scale. On Friday, I was accepted to Berkeley with zero aid. Which brings us back to my aforementioned concern: decisions.

Though I was disappointed with the quantity of labs I found studying plant genome editing, I was blown away by what I did find, Dr. Pamela Ronald’s lab. Dr. Ronald is the pinnacle of what I aspire to be; not only incredibly prolific, but doing research to benefit humanity, while emphasizing the importance of science communication. She’s appeared on videos with Neil DeGrasse Tyson, given a TED talk with millions of views, and co-wrote Tomorrow’s Table, which I’m currently reading. Everything she says precisely reflects my views on GMOs, their potential, and the challenges posed by skepticism fueled by misinformation. She speaks eloquently and effectively, always careful to never alienate any fraction of her audience. She’s speaking at a research symposium next month, and I am highly considering ditching my classes to attend, just to hear what she has to say. Anyway, I just thought her research was too interesting not to write about! Plus, there’s a lot more I didn’t get into, so there might be more about the Ronald lab!

So what does Serene do if she doesn’t get into a cool lab like this one? Go on a transformative journey and realize she actually wants to be a car salesperson? Spontaneously combust? Comment your guesses below and tune in next week to learn with me!

Prevalence of flooding and Sub1A Rice: https://cropgeneticsinnovation.ucdavis.edu/engineering-submergence-tolerance-rice

Sub1A Rice: Ronald PC, Adamchak RW. 2018. Tomorrow’s table : organic farming, genetics, and the future of food. New York, Ny: Oxford University Press.

Marker-associated breeding: https://pmc.ncbi.nlm.nih.gov/articles/PMC2610170/ 

Golden Rice transgenes: https://ift.onlinelibrary.wiley.com/doi/10.1111/j.1541-4337.2007.00029_7.x 

IR64 vs Sub1: https://www.youtube.com/watch?v=shCHe1eAQoQ

Sub1’s financial discrepency: http://books.irri.org/AR2023_content.pdf

Cambridge’s rough estimates: https://www.cambridge.org/core/journals/environment-and-development-economics/article/information-quality-adoption-of-climatesmart-varieties-and-their-economic-impact-in-floodrisk-areas/4BD406346E8A96CAC3B28D01C44F4EC9 

Projects at the Ronald lab: https://cropgeneticsinnovation.ucdavis.edu/initiatives

Carotenoid-enriched rice: https://cropgeneticsinnovation.ucdavis.edu/sites/g/files/dgvnsk6996/files/inline-files/Olivers%20Nature%20Comm%20paper_1.pdf