Fri. Jan 21st, 2022

It’s not easy for life in Chile’s relentless Atacama Desert: a rugged, hostile place known for being the planet’s driest non-polar desert.

But against the odds, life somehow survives in these barren badlands, which have a history of farming that stretches back thousands of years.

Identifying the mechanisms behind these unlikely successes is a task that is more important today than perhaps ever before, as it could reveal the secrets behind making food grow in a world that is getting hotter and drier with each passing year.

In a new study, scientists have discovered some of these hidden tricks and discovered the genetic underpinnings of a number of adaptations that allow plant life to thrive even under the withering, extreme conditions of the Atacama Desert.

Researcher Gabriela Carrasco is studying plant samples in the Atacama Desert. (Melissa Aguilar)

“In an era of accelerated climate change, it’s crucial to uncover the genetic basis to improve crop production and resilience under dry and nutrient – poor conditions,” said plant systems biologist Gloria Coruzzi of New York University.

Over a period of 10 years, Coruzzi and an international team of researchers studied the Atacama plant life in 22 places in the desert landscape, both in situ and also outside the site – carefully transporting plant and soil samples back to the laboratory, frozen in liquid nitrogen to preserve them for genomic analysis.

In all, 32 of the most dominant plants in the desert had their transcriptomes sequenced, which were then compared with 32 closely related species from elsewhere, none with genetic adaptations to Atacama’s environment.

“The goal was to use this evolutionary tree based on genome sequences to identify the changes in amino acid sequences encoded in the genes that support the development of the Atacama plant’s adaptation to desert conditions,” says Coruzzi.

The comparison technique – an example of what is called phylogeny – yielded 265 positively selected genes, suggesting that they correlated with mutations that may confer benefits in the Atacama Desert.

Further analysis revealed that 59 of these genes also appear in one of the most studied model organisms in plant biology, Arabidopsis, where they have been linked to physiological and molecular processes that can improve the resilience of plants under extreme environmental conditions, the researchers say.

In other words, these genes – which are positively selected in Atacama desert plants – are already known to enable Arabidopsis to resist high radiation and temperature stress, regulate flower development and flowering time, help defend against pathogens and help with water and nutrient uptake.

From the sound of it, it sounds almost like an evolutionary tool for how to survive as a plant in one of the most inhospitable environments on Earth, and the good news is that some of the same genetics can also be found in food crop species – which means that we may have a better idea of ​​which crops we should plant where, when the world warms, and also how we can best breed, adjust and future-proof them.

The work “is directly relevant to regions around the world that are becoming increasingly arid, with factors such as drought, extreme temperatures and salt in water and soil posing a significant threat to global food production,” says senior author and plant systems biologist Rodrigo Gutiérrez from the Papal Catholic University of Chile.

“Since some Atacama plants are closely related to basic crops, including cereals, legumes and potatoes, the candidate genes we identified represent a genetic goldmine for constructing more resistant crops, a necessity given the increased desertification of our planet.”

The results are reported in PNAS.

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By Victor

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