Plants pause, play and fast forward growth depending on types of climate stress

(Press-News.org) New research could help engineer crops that recover after extreme weather events

Plants pause their growth during stress, then press play when conditions improve, helping them recover and live on to produce food, according to a new study.

Published today in New Phytologist UBC researchers have pinpointed the genes and pathways responsible for recovery from the environmental stress of cold snaps in winter or overloads of salt when coastal fields flood.

“With a changing climate and extreme weather events becoming more frequent, the work could help create climate resilient crops, where genetically engineered crop plants will recover faster and more efficiently after climate events,” said first author Olivia Hazelwood, doctoral student in the UBC department of botany. “Consequently, these plants will be able to complete their life cycle and produce foods during the harvest season, even after experiencing snow storms, heat waves or flooding.”

The researchers found that plants paused root growth when undergoing stress from cold and salt, then resumed growth when these stresses were removed and the plant was allowed to recover for an equal period of time to the stress conditions.

In this and another paper submitted for peer review, researchers have also identified the gene pathways for heat stress, finding plants ‘fast forward’ their growth in heat and then ‘pause’ until temperatures drop. “We also found plants can recover from osmotic, or drought, stress, but it takes a little longer,” said senior author Dr. Arif Ashraf, assistant professor in the UBC department of botany. “We refer to it as ‘pause and push’, because it needs that time to ‘push’ through and recover.”

Investigating genetic pathways for recovery

 

In the lab, the researchers applied cold and salt stress to a model plant and then measured the root growth. They then tested it in two wild grasses related to crop plants. Finding similar responses across the three plants, they suspected a similar cellular response was involved.

 

Since root growth relies upon cellular division, Hazelwood used fluorescently marked proteins to examine this process, including how many cells were actively dividing during and after stress, and when certain proteins related to cell division were active.

 

“After counting thousands of cells for months, I saw that certain proteins were present in fewer cells when plants are under cold, drought and salt stress, but within about 24 hours of being put back into optimal growth conditions, their numbers returned to normal,” she said.

Key to this growth cycle are particular genes called Cyclin-dependent Kinase A;1, or CDKA;1. Inhibiting this gene prevented plants from recovering from stress, the researchers found.

By identifying the specific mechanisms, pathways, and genes involved in plant recovery from cold and salt stress, and by showing these are conserved across different plant species, the research opens the door to breeding and genetically engineering crops with enhanced tolerance for environmental stressors.

“We can’t stop heatwaves or snow storms,” said Dr. Ashraf. “So we’re pinpointing genes that can help the plants recover from these events and still produce in time for harvest.”

The team now plans to show the recovery process also happens in different Canadian crop plants, including wheat varieties, said Hazelwood. “In two to three years, we hope to adjust these genetics of these Canadian crop varieties and created our own CRISPR-edited lines that are better able to cope with a changing climate.”  

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