More resistant plants against drought – Biologisk Institut - Københavns Universitet

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16. februar 2018

More resistant plants against drought

Plant drought resistance

Given the growing world population and the climate change exposing large areas of cultivated land to periods of severe drought it is necessary to understand how plant drought resistance works and be ready to produce plants that thrive better under reduced water conditions.

Several companies around the world are already testing proven technologies, but new research from Department of Biology, University of Copenhagen has just provided new molecular insight into how increased plant drought resistance may be engineered. The results have recently been published in the scientific journal Genes & Development.

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A molecular mystery solved
Protein farnesylation has been recognized to be of major importance in plant biology since the 1990s when it was found that farnesyl transferase mutants exhibit at least two properties different from wild type plants: They are extremely resistant to drought, possibly as a consequence of their pronounced sensitivity to the drought stress hormone abscisic acid, and they fail to correctly control the size of the plant stem cell niche (meristem).

Although the knowledge that inhibition of protein farnesylation leads to drought resistance has been put to practical use with the development of drought-resistant oil-seed rape that represses farnesyl transferase in response to drought, the genetic basis of these important phenotypes remains unclear. This gap in knowledge has developed into a classical unsolved problem of plant molecular genetics, and it is of practical importance, because it prevents technology transfer to crops more distantly related to Arabidopsis than oilseed rape.

-        ‘Our study provides unusually clear results demonstrating that all of these very different phenotypes can be explained by requirement for farnesylation of a single, hitherto elusive factor, Heat Shock Protein 40 (Hsp40): abscisic acid hypersensitivity, drought resistance and enlarged meristems seen in farnesyl transferase mutants are fully recapitulated in plants expressing farnesylation-deficient Hsp40. These are exceptional results, since farnesyl transferase may modify hundreds of target proteins’, says associate professor Peter Brodersen, Department of Biology.

Highly evolutionary conserved
The results represent a major breakthrough because they provide a long-sought molecular explanation for phenotypes of outstanding basic and applied interest, and show that the key targets have farnesylation sites deeply conserved in all plants.

-       ‘Our study also takes the first step to identify specific molecular consequences of lack of Hsp40 farnesylation. Profiles of microRNA (miRNA) accumulation reveal that a distinct set of abiotic stress-related miRNAs controlled by the same transcription factor fails to be transcribed in farnesyl transferase mutants or in mutants specifically defective in Hsp40 farnesylation’, Peter Brodersen continues.

Because farnesylated Hsp40 is deeply conserved in plants, and indeed in all eukaryotes, it now becomes an obvious possibility to transfer existing technology from Arabidopsis and oilseed rape to more distantly related crops, such as the grasses wheat and maize.

The research group has patented their findings and has already entered into a collaboration with the Canadian agricultural and biofuel biotechnology company “Perfomance Plants Inc” to help farmers, industry and biofuel users in the challenges of feeding and fueling the world in the future.