"We make our world significant by the courage of our questions
and the depth of our answers."
- Carl Sagan
"We make our world significant by the courage of our questions
and the depth of our answers."
- Carl Sagan
I’m a master’s candidate in Plant Breeding and Genetics at Montana State University’s Durum Breeding Lab, driven by a passion for understanding the genetic factors that will shape wheat’s success in tomorrow’s climates. In both lab and field settings—using controlled-environment aeroponic systems and traditional trials—and applying quantitative analytics, I investigate how genetic and environmental variables influence tillering, biomass allocation, and yield stability—with the goal of developing adaptable, high-performing cultivars. Equally devoted to outreach, I translate these complex insights into clear, engaging communications—whether through posters, presentations, or other media—so that both scientific peers and the broader community can connect with—and benefit from—the latest advances in wheat breeding.
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Sergei O’Sullivan, Caleb Hale, Jack Martin, Michael Giroux
National Association Plant Breeding | 2025 | Kona, HI
Abstract:
The TEOSINTE BRANCHED1 (TB1) gene is a key regulator of shoot branching and tiller formation in monocots, including tetraploid durum (Triticum turgidum) and hexaploid modern wheat (Triticum aestivum). While its aboveground effects have been well characterized emerging research suggests that TB1 may also influence root system architecture, a critical trait for nutrient uptake, stress resilience, and agronomic performance of wheat. In this study, we investigate root branching in durum wheat near isogenic lines (NILs) segregating for four different TB1 alleles combinations across polyploid genomes, using a custom aeroponic system to capture clean, high-resolution root phenotyping data. By comparing total root length, root number, and branching metrics across genotypes, we aim to quantify how allelic variation at TB1 contributes to root development. Preliminary results indicate that TB1 mutant alleles significantly increase total crown root number with no detectable difference in seminal root count, suggesting that TB1 has influence on post-germination root initiation. Going forward, we aim to assess how TB1 functions in agronomic systems and its potential for breeding regionally adapted cultivars by conducting hormonal and metabolic profiling of TB1 alleles across planting densities, and by evaluating root response to varying fertilizer regiments in an aeroponics system. This work will reveal how TB1 shapes shoot-root coordination and whether specific alleles confer advantages in environments with early-season moisture followed by terminal drought.
Reference:
1.) Callwood, J. B., Cowling, C. L., Townsend, E. G., Malik, S., Draves, M. A., Khor, J., Marshall, J. P., Sweers, H., Walley, J. W., & Kelley, D. R. (2025). Identification of phenotypic and transcriptomic signatures underpinning maize Crown Root Systems. Plant Phenomics, 7(1), 100008. https://doi.org/10.1016/j.plaphe.2025.100008
2.) Dixon, L. E., Greenwood, J. R., Bencivenga, S., Zhang, P., Cockram, J., Mellers, G., Ramm, K., Cavanagh, C., Swain, S. M., & Boden, S. A. (2018). teosinte branched1 regulates inflorescence architecture and development in bread wheat (triticum aestivum). The Plant Cell, 30(3), 563–581. https://doi.org/10.1105/tpc.17.00961
3.) Gaudin, A. C., McClymont, S. A., Soliman, S. S., & Raizada, M. N. (2014). The effect of altered dosage of a mutant allele of Teosinte branched 1 (TB1-ref) on the root system of modern maize. BMC Genetics, 15(1). https://doi.org/10.1186/1471-2156-15-23
4.) Volkman, M. M., Martin, J. M., Hogg, A. C., Wright, L., Hale, C., Carr, P. M., & Giroux, M. J. (2022). Durum wheat teosinte branched1 null mutations increase tillering. Crop Science, 62(4), 1522–1530. https://doi.org/10.1002/csc2.20775
Oiestad, A. J., Blake, N. K., Tillett, B. J., O’Sullivan, S. T., Cook, J. P., & Giroux, M. J.
Crop Science | 2025 | Journal article ( https://doi.org/10.3390/plants14040512 )
Abstract:
"Shifts in the environment due to climate change necessitate breeding efforts aimed at adapting wheat to longer, warmer growing seasons. In this study, 21 modern wheat (Triticum aestivum L.) cultivars and 29 landraces were screened for flag leaf starch levels, with the goal of identifying a genetic marker for targeted breeding. The landrace PI 61693 was identified as having exceptionally high flag leaf starch values. Yield trials were carried out in a Berkut × PI 61693 recombinant inbred line (RIL) population and a negative correlation was observed between leaf starch, flowering time, and yield. Genetic mapping identified a Quantitative Trait Loci (QTL) explaining 22–34% variation for leaf starch, flowering time, biomass, and seed yield. The starch synthase TraesCS7D02G117800 (wSsI-1) is located in this region, which possibly accounts for leaf starch variation in this population; also within this QTL is TraesCS7D02G111600 (FT-D1). Sequencing of FT-D1 identified a single base pair deletion in the 3rd exon of the Berkut allele. This indel has recently been shown to significantly impact flowering time and productivity, and likely led to significant variation in flowering date and yield in this population. Here, we illustrate how allelic selection of FT-D1within breeding programs may aid in adapting wheat to changing environments."
Sergei O'Sullivan
Montana Wheat and Barley March Madness | 2025 | Bozeman, MT
Abstract:
CRISPR has quickly become one of the most promising tools in plant breeding, offering a precise, efficient way to generate targeted mutations. Unlike traditional EMS mutagenesis, which introduces thousands of random mutations across the genome, CRISPR allows us to edit specific genes of interest—eliminating the need for massive screening and reducing the risk of unintentionally damaging important traits. While EMS has played a major role in developing useful alleles, it often comes at the cost of background noise and reduced genetic diversity over generations of backcrossing and selection.
One major concern in modern breeding programs is the ongoing loss of genetic diversity as elite lines are repeatedly crossed and narrowed for specific traits. CRISPR offers a way to reintroduce variation without completely disrupting elite backgrounds. It also allows for the exploration of gene function in a much more controlled way, giving breeders the ability to create novel alleles or mimic naturally occurring ones lost in domestication.
This project looks at how CRISPR is reshaping our approach to mutagenesis and where it fits within real-world breeding pipelines. Its speed, precision, and adaptability make it an attractive tool for breeding labs—especially those looking to speed up trait development without compromising genetic integrity.
Sergei O'Sullivan
Montana State University - Office of Sustainability | 2025 | Newsletter
Since the dawn of agriculture, plant breeding has been a cornerstone of civilization across the globe, shaping societies and sustaining populations. From the first domestication events to the modern day, plant breeding has evolved greatly over the span of many millennia. Early plant breeding efforts resulted in significant advancements in crop improvement, leading to higher-yielding crops that have promoted the exponential growth of the human population. This increase in food supply through breeding efforts has been the catalyst for wealth and prosperity, the impetus for trade and growth, and ultimately, the foundation of all societies that have ever existed.
Despite all the successes plant breeding efforts have fostered, the path forward has not been without challenges. As the field of plant breeding progresses, so do the challenges that breeders must overcome. Today, plant breeders face unprecedented challenges in the wake of climate change, demonstrated by increasing unpredictability in weather patterns, rising pest and disease pressures, and numerous other environmental stresses. These consequences of climate change threaten current crop production across the globe, and action must be taken.
Plant breeding programs in the Department of Plant Science and Plant Pathology at Montana State University aim to mitigate, if not improve upon, the projected yield losses caused by increasing environmental stress created by climate change. How, you may ask? This is being accomplished through the combination of conventional breeding techniques (crossing two plants to create a superior offspring) and the utilization of advancements in the field of plant biotechnology.
Conventional breeding techniques have and will continue to play a crucial role in agricultural development. These techniques are the bedrock of advancing plant varieties, as demonstrated in the Green Revolution of the 1950s with Norman Borlaug’s development of semi-dwarfing wheat varieties, which drastically improved yields and have been credited with increasing the Earth’s carrying capacity. Conventional breeding has undoubtedly played a major role in the improvement of crops, but in recent decades, large strides in progress of advancing crops has become increasingly challenging due to breeding populations lacking genetic variation- the key to ALL crop improvement.
When said genetic variation is nonexistent, breeders must turn to sources outside of their breeding populations to find such variation. This is often done by incorporating variants of genes from other breeding programs or heirloom populations. When no allelic variation is found here, breeders create their own variation.
A gene central to my own research, Reduced height1 (Rht), plays a significant role in determining the height of wheat. This is the same gene that Norman Borlaug leveraged during the Green Revolution while developing semi-dwarfing wheat, previously discussed. In durum wheat, or pasta wheat, taller plants allocate more resources to their inedible structures due to elevated stem elongation. Further, the tall stature can lead to an increasing risk of wind damage— commonly know as lodging. Together, this ultimately can lead to reduced yield. Conversely, the mutant variant of rht results in wheat too short to harvest, being especially concerning in arid conditions commonly experienced in Montana. So what is the solution? Utilizing a technique called, Targeted Induced Local Lesions in Genomes” (TILLING), the Giroux Durum breeding team at MSU created a mutation in rht that results in intermediate height falling between a tall and short stature. This intermediate height strikes an optimal balance, avoiding shortcomings of either short or tall wheat.
This employment of biotechnology to improve wheat would not have been possible without the advancements made in recent decades regarding the field of plant biotechnology. Plant biotechnology is a relatively new scientific endeavor, (at least in contrast to the history of conventional breeding), that has significantly enhanced traditional plant breeding efforts by introducing precise and efficient tools to develop improved crop varieties. Through advancements such as genetic engineering, marker-assisted selection, and tissue culture, biotechnology allows breeders to introduce specific traits that enhance crop resilience, nutritional content, and overall performance of any crop. For example, the use of genetic markers enables breeders to select for drought tolerance or disease resistance with greater accuracy, reducing the time needed to develop climate-resilient varieties. Additionally, genetic modification techniques, such as CRISPR-Cas9, provide the ability to precisely edit plant genomes, allowing for the targeted improvement of key traits without the need for extensive crossbreeding. These innovations have opened new possibilities for addressing agricultural challenges, from combating emerging pests and diseases to adapting crops to unpredictable weather conditions caused by climate change. As a result, plant biotechnology is poised to play an increasingly vital role in ensuring food security and sustainability for future generations.
Plant biotechnology is already making significant strides in improving crops to meet the demands of a changing climate and a growing population. Through genetic engineering and advanced breeding techniques, scientists have developed crops with enhanced drought tolerance, allowing them to thrive in water-scarce environments. Pest-resistant varieties, such as Bt corn, reduce the need for chemical pesticides, leading to more sustainable farming practices and lower environmental impact. Additionally, biofortified crops, such as Golden Rice enriched with vitamin A, address critical nutritional deficiencies in developing regions. Advances in biotechnology also enable crops to utilize nutrients more efficiently, improving yields while reducing fertilizer dependency. These breakthroughs demonstrate the potential of this intersection of traditional breeding and biotechnology to revolutionize agriculture, making it more resilient, efficient, and sustainable in the face of global challenges.
As plant biotechnology (and traditional breeding efforts) advances to tackle agricultural challenges, its success in combating climate change depends not only on scientific progress but also on public trust. The adoption of biotechnological innovations is crucial to ensuring food security and environmental sustainability in this increasingly unpredictable world. However, skepticism fueled by misinformation has shown to, and will continue to hinder progress. Building trust requires transparency, open dialogue, and clear communication of the benefits and safety of these advancements. Ultimately, fostering trust in plant science and biotechnology is not just about accepting innovation; it is about ensuring the long-term resilience of agriculture and the well-being of future generations. Trust the science.
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