Researchers at Penn State screened nearly 500 lines of corn over four years in South Africa
According to Penn State researchers, the discovery of a gene that regulates the angle of root growth in corn is a new tool to enable the breeding of deeper-rooting crops with an enhanced ability to take up nitrogen.
The gene, called ZmCIPK15- a moniker indicating where it is located in the genome and how it functions- was found to be missing in a naturally occurring mutant corn line that grows roots at steeper angles that make them go deeper into the soil. They identified the gene using a technique called a genome-wide association study, which involves a painstaking statistical analysis of a genome-wide set of genetic variants in different plant lines to see what genes are associated with a trait.
Identifying a gene that controls the angle of root growth in corn- influencing the depth to which roots forage- is important because deeper roots have a greater ability to capture nitrogen, according to research team leader Jonathan Lynch, distinguished professor of plant science in Penn State’s College of Agricultural Sciences.
Researchers at Penn State screened nearly 500 lines of corn over four years in South Africa to find the gene regulating the angle of roots. Field experiments at Penn State’s Russell E Larson Agricultural Research Center and greenhouse experiments at the University Park campus were conducted to confirm the phenotype of the mutant and wild-type plants and to test the functional utility of changes in root angle for nitrogen capture.
Roots of selected plants were excavated and measured, validating the functional importance of the ZmCIPK15 gene. It caused an approximate 10-degree change in root angle, noted Hannah Schneider, a former postdoctoral scholar in the Lynch lab, now a faculty member at Wageningen University in the Netherlands, who spearheaded the research.
In findings recently published in Plant, Cell and Environment, the researchers reported that a steeper root growth angle markedly improved nitrogen capture. In field studies under suboptimal nitrogen availability, the cipk15 mutant with steeper growth angles had 18 per cent greater shoot biomass and 29 per cent greater shoot nitrogen accumulation compared to the wild type, after 70 days of growth.
