What makes the roots of a plant grow in the direction of gravity? New PNAS research has uncovered four genes

What happens in cornfields is easy to overlook, but maize root structures play an important role in acquiring water and nutrients, affecting drought tolerance, water use efficiency and sustainability
.

The first step in achieving this goal is to learn genes related to the action of gravity, that is, the response
of root growth to gravity.

When a germinating seed flips to the side, some roots will suddenly turn sharply in the direction of gravity, while others will be slightly slower
.

The map allowed the researchers to find the right neighborhoods in the genome — regions of hundreds of genes — but they are still a long way from determining a specific gene for Earth-orientation
.

"Because we have previously performed the same experiments on distant relatives of Arabidopsis plants, we were able to match genes
within genome-related regions of both species.

Study co-author Matt Hudson, a professor in the Department of Crop Science at the University of Illinois, added: "We looked at an understudied trait of maize that is important for many causes, particularly in the context
of climate change.

Corn and Arabidopsis thaliana (relatives of a small mustard veola that has been described in detail by plant biologists) evolved over an evolutionary history of about 150 million years
.

In more closely related species, genes tend to be arranged in approximately the same order in the genome (e.

"I think it's pretty cool that we can identify genes that we can't find by comparing the genomic spacing of unrelated plant species," Hudson said
.

Spalding notes that this approach could be particularly successful because precise measurements are made
in a normal environment.

"Normally, maize researchers measure traits of interest in a field, while Arabidopsis researchers tend to grow their plants in growth chambers
," he said.

Even though traits can be measured in a common environment, not all traits are suitable for this approach
.

Spalding said: "Gravity may be particularly suitable for studying through this method, as it may be the key to the initial specialization of the shoots and roots after the successful colonization of the
land.

Hudson points out that gravity will also be the key
to colonizing different landscapes.

"NASA is interested in growing crops on other planets or in space, and they need to know what
you need to cultivate to make that happen," he said.

Original:

“Leveraging orthology within maize and Arabidopsis QTL to identify genes affecting natural variation in gravitropism,” is published in the Proceedings of the National Academy of Sciences [DOI: 10.