Cereal crops have a secret trait that gives them deeper roots

Scientists at Penn State have discovered a trait that provides some cereal crops with roots that can push through dry, compacted soils. By harnessing this trait, experts could grow crops with stronger roots, higher yields, and more resistance to climate change. 

“This discovery bodes well for American and global agriculture because the trait helps corn, wheat and barley grow deeper roots, which is important for drought tolerance, nitrogen efficiency and carbon sequestration,” said study co-author Professor Jonathan Lynch. “Breeding for this trait should be helpful in developing new crops for climate mitigation.”

For deeper root penetration in compacted soils, the plants use multiseriate cortical sclerenchyma (MCS). Cereal crops with the MCS genotype have a greater concentration of lignin that creates tough, rigid roots.

The extra lignin gives the MCS roots greater tensile strength and greater root tip bending to penetrate hard soil layers.

The experts found that corn genotypes with MCS had root systems with 22 percent greater depth and 39 percent greater shoot biomass in compacted soils compared to lines without MCS.

According to study lead author Hannah Schneider, soil compaction reduces porosity, limits water infiltration, reduces aeration and restricts root growth by presenting a physical impediment.

“Compacted soil layers constrain crop productivity by restricting root growth and exploration in deeper soil layers, which in turn limits access to nutrients and water,” said Schneider. “Plants with roots that are able to penetrate hard soil and forage deeper have an advantage in capturing water and nutrients – ultimately performing better in drought or low soil fertility.”

To visualize the anatomy of the plant roots, the researchers used laser ablation tomography (LAT). This technology was created by Professor Lynch’s team in 2011.

Genetic variation for MCS was found in each of the cereal crops examined by the researchers. They noted that heritability was relatively high, which suggests that this trait can be selected in breeding programs. Overall, MCS was present in 30 to 50 percent of modern corn, wheat, and barley.

Schneider pointed out that the implications of corn crops growing deeper roots to range farther for water and nutrients – and as a consequence producing larger yields – would be immense in regions where the populace is food-insecure. 

“We observe MCS in corn, wheat, barley and many other cereal crops, and our work suggests that many of the benefits of MCS may be analogous across different species,” said Schneider. “MCS could be an important trait for stress tolerance and increased yields in cereal crops.”

The study is published in the journal Proceedings of the National Academy of Sciences.

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By Chrissy Sexton, Earth.com Staff Writer