A new study published in Cell demonstrates how combining citizen science data with controlled research experiments can help scientists better understand how plants adapt to different environments.
The research, led in part by Iowa State University agronomy professor Jianming Yu, examined flowering patterns in switchgrass and other perennial prairie grasses. By integrating artificial intelligence-powered analysis of thousands of publicly shared photographs with field experiments and genetic research, scientists identified genetic mechanisms that help explain differences in flowering behavior across regions.
Researchers analyzed nearly 44,000 online photographs of warm-season grasses that included time and location information. The AI screening process produced about 5,000 observations of flowering switchgrass, big bluestem, little bluestem and Indian grass. Across all four species, flowering generally occurred earlier in northern locations than in southern locations.
However, when researchers grew genetically diverse switchgrass samples at 10 research sites across the Midwest and Gulf Coast regions, they observed the opposite trend. Plants flowered an average of 2.3 days later for every degree of latitude farther north.
The apparent contradiction prompted a deeper investigation into the genetic and environmental factors influencing flowering time.
Genetic Variants Linked to Regional Adaptation
Focusing on switchgrass, researchers analyzed genetic mapping populations and identified a network of genes associated with flowering. The team found three major haplotypes, or combinations of genetic variants, linked to flowering behavior. These haplotypes were concentrated in different geographic regions, including one commonly found in the Midwest and another prevalent along the Gulf Coast.
Further analysis showed that temperatures between April 25 and May 5 had the strongest relationship with flowering time. Warmer temperatures during that period accelerated flowering by an average of 3.4 days for each degree Celsius increase.
The Gulf Coast-associated haplotype, designated H1, flowered approximately 45 days later than the Midwestern haplotype, H2. Researchers also found that H2 was more responsive to temperature changes during the critical spring period.
The differences appear to reflect adaptation to local environmental conditions. In northern regions, earlier flowering allows switchgrass to complete reproduction and prepare for winter before colder fall temperatures arrive. In southern regions, delayed flowering helps plants avoid reproducing during the hottest part of summer while taking advantage of generally milder autumn conditions.
Combining Data Sources
The study highlights the value of integrating publicly collected observations with traditional plant breeding and genetics research.
According to the researchers, the flowering adaptations observed in natural habitats would likely have been missed without the large public database of photographs. At the same time, the genetic basis of those adaptations could not have been identified without controlled experiments using genotyped plants.
The study, titled “Harnessing citizen science to contextualize adaptation mechanism discovery,” included 27 co-authors from multiple institutions, including scientists from the U.S. Department of Agriculture.
Researchers said the work demonstrates the potential of combining citizen science observations with designed experiments to study plant adaptation across broad geographic and time scales. The approach may help future studies better understand phenotypic plasticity, or how plants alter their growth and development in response to environmental conditions.
Yu said publicly available observational data should be incorporated into plant research whenever appropriate, allowing scientists to compare findings from controlled experiments with patterns observed in natural environments.
Source: Iowa State University, "Integrating ‘citizen science’ with experimental data helps uncover how plants adapt"