A research team led by Markus Schmid has identified a new player regulating plant development under low temperatures. The researchers searched for mutants that have strong growth defects when grown at low temperatures but look otherwise normal. They found the porcupine mutant and showed that the PORCUPINE gene is crucial for normal plant development at low temperatures. Their results are published as Brief Communication article in the journal Nature Plants.
Plants react to changing temperatures by adjusting their development and growth rate. The mutant, that lost the active PORCUPINE gene, grows very slowly at lower temperatures (16°C), displays sever developmental defects and is not able to produce seeds. However, it looks almost like non-mutated plants when growing at favourable temperatures (23°C). The researchers around Markus Schmid concluded that the PORCUPINE gene is required specifically at low temperatures and is crucial for adjusting the plant development and growth to low temperatures.
A recently suggested important mechanism that allows plants to adjust their growth and development to changes in temperature is the so-called alternative splicing (see also below). This process enables a single gene to produce different protein versions depending on which parts of the gene are spliced together and translated. The resulting proteins are altered in their structure and can have different functions. There are factors that regulate which protein variant is synthesised by alternative splicing. PORCUPINE appears to be one of those factors that regulates alternative splicing events under cold temperatures.
Many of the alternative splicing events that take place in the non-mutated plant at lower temperatures are missing in the mutant that lost the active PORCUPINE gene. “We think that PORCUPINE plays a crucial role for connecting plant responses to low temperature with plant development via alternative splicing”, explains Markus Schmid. “This is a new but very complex regulation pathway that we just now start to explore.”
The PORCUPINE gene got its name from the special look of the mutant that lost the functional PORCUPINE gene. The leaves of the mutant are radialised and the hairs (trichomes) on the surface of the mutant are often branched more frequently, giving the mutant a very “spiky” appearance – reminiscent of a porcupine.
|What is alternative splicing?|
|When a gene gets activated its DNA sequence is first transcribed into pre-mRNA (precursor messenger ribonucleic acid). Many pre-mRNAs in plants and animals are than spliced to remove parts (introns) that do not contain information for the encoded protein. The remaining “exons” are stitched together to form a mature mRNA, which is subsequently translated into a protein. Depending on which intros are spliced out and which exons are joined together, different mRNAs can be produced from a single gene, resulting in different protein versions.|
Giovanna Capovilla, Nicolas Delhomme, Silvio Collani, Iryna Shutava, Ilja Bezrukov, Efthymia Symeonidi, Marcella de Francisco Amorim, Sascha Laubinger & Markus Schmid (2018) Nature Plants, doi.org/10.1038/s41477-018-0176-z.
PORCUPINE regulates development in response to temperature through alternative splicing
Link to the publication: https://www.nature.com/articles/s41477-018-0176-z
For more information, please contact:
Markus Schmid, professor
Umeå Plant Science Centre
Department of Plant Physiology