Welcome to Pocket Science: a glimpse at recent research from Husker scientists and engineers. For those who want to quickly learn the “What,” “So what” and “Now what” of Husker research.
What?
It’s no surprise that genes are the first thing people think of in understanding the heritability of traits. “Good genes” is the common explanation given. But genetic science is now moving beyond a focus on individual genes to consider a larger, more important factor: An offspring’s traits and functions aren’t determined by a single “trait” gene. Instead, they result from interactions among complex genetic networks. And those networks are guided by master regulatory genes, or “hotspots.”
Gen Xu, research assistant professor with the Department of Agronomy and Horticulture, and Jinliang Yang, the Charles O. Gardner Professor of Agronomy, are using this scientific insight to point out key ramifications for crop breeding. As explained in their new paper in Nature Communications, the Husker scientists and their collaborators analyzed hundreds of corn seedlings and identified regulatory hotspots (technical name: trans-eQTLs) that help corn hybrids outperform their parents, a phenomenon known as hybrid vigor, or heterosis. By balancing or buffering weaker gene variants, heterosis contributes to improved plant performance and yield. One important regulator they identified, ZmR1, appeared to give hybrids significantly improved growth and vigor.
So what?
This strengthened genetic understanding has direct relevance for modern crop breeding, especially for understanding how hybrids can achieve increased vigor. Xu’s research underscored, for example, that for hybrids, traits and functionalities aren’t a simple averaging of the two parents. One parent’s stronger regulatory systems — gene co-expression networks, scientists call them — can help a hybrid compensate for weaker genetic variants from the other parent. The potential benefits include significant improvements in yield or drought tolerance.
The greater the understanding of these master control systems, the greater the chances for improved plant breeding.
Now what?
Xu plans to deepen the understanding of this crop science by looking at the full range of biological “omics” — traits-focused DNA, regulation-connected RNA, function-affecting proteins and activity-relevant metabolites. As this knowledge progresses, crop breeders ultimately may be able to target these genetic regulatory networks to create more resilient hybrids more efficiently. Current breeding methods can be time-consuming and involve considerable trial and error. Using advanced quantitative models that focus on genetic hotspots could more quickly predict the best-performing parental crosses.
This science also offers promise for hybrid-related gene editing. Bioengineers could target key regulatory hubs to promote heterosis and achieve sustained vigor across succeeding generations.
Thanks to this increased understanding, credit for the progress would go less to “good genes” than to “good hotspots.”
