Sigridur Dalmannsdottir
Forsker
(+47) 465 46 249
sigridur.dalmannsdottir@nibio.no
Sted
Tromsø
Besøksadresse
Holtvegen 66, 9016 Tromsø
Forfattere
Sigridur DalmannsdottirSammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. Aamlid Sigridur Dalmannsdottir Marit Jørgensen Kristoffer Herland Hellton Akhil Reddy Pashapu Ievina Sturite Mallikarjuna Rao Kovi Helga Amdahl Carl Gunnar Fossdal Odd Arne RognliSammendrag
Timothy ( Phleum pratense L.) is the predominant forage grass species in the northern parts of the Nordic region. Because of the long andharsh winters and a short growing season, most of it with continuous light, the need for locally adapted timothy seed has been recognizedfor more than a century. However, the seed production of timothy in these marginal environments is unpredictable with acceptable seedyield and quality on average only every third year. Thus, a multiplication scheme for the northern cultivars was established with only pre-basic seed produced in the north, and basic and certified seed produced further south to secure enough seed of good quality. In recentdecades this scheme has been more or less abandoned with continous generations produced in the south. Farmers are complaining andare questioning whether the cultivars has changed and lost winter hardiness. We studied freezing and ice-encasement tolerance of generations of the the northern timothy cultivars ‘Engmo’ (old landrace) and ‘Noreng’(synthetic) multiplied for one, two or three generations in Central, Southern and Northern Norway. The trials introduce very largedifferences in mean temperature, growing degree days and photoperiod between place of parental origin and sites of multiplication so theeffects on fitness observed could arise from both selection and and induced epigenetic changes. Large changes (loss) in freezing and ice-encasement tolerance were observed, especially at the southern location in the first generation.The cultivars behaved differently and there were significant interactions. The extreme phenotypic changes observed might be explained bygenetic selection or epigenetic memory of the environmental conditions experienced during seed production, or a combination of the two.We are currently analysing GBS data of all generations and this will be used to test whether genetic shifts has occured during themultiplication in the different environments.
Forfattere
Akhil Reddy Pashapu Sigridur Dalmannsdottir Marit Jørgensen Marian Schubert Odd Arne Rognli Mallikarjuna Rao KoviSammendrag
The sustainable production of perennial grasses in Northern Norway is at risk due to the ongoing climate change. The predicted increase in temperatures and variable weather patterns are further expected to create challenges for winter survival of timothy (Phleum pratense L.). Knowledge about the molecular mechanisms underlying freezing tolerance is crucial for developing robust cultivars. The current study is aimed at identifying genes involved in freezing stress response of timothy and studying gene expression differentiation due to field selection in contrasting environments using RNAseq. Four timothy cultivars were field tested for three years in Tromsø and Vesterålen, in Northern Norway. The surviving material from the field tests, along with plants raised from the original seed lots, were subjected to freezing tests. LT50 values varied across cultivars and materials. Many genes coding for transcription factors and proteins known to play an important role in freezing tolerance, like dehydrins, c-repeat binding factors, and late embryogenesis abundant proteins were upregulated with decreasing temperatures. Moreover, genes associated with glycolysis/gluconeogenesis, TCA cycle, glutathione metabolism, proteasome pathways and genes encoding autophagy-related proteins, plasma membrane-associated proteins, sugar and amino acid transporters had elevated expression in field survivors compared to plants raised from the original material. The lower freezing stress tolerance of field survivors despite the elevated expression of several stress-responsive genes might be due to a combination of selection in the field and the age effect. Furthermore, differences in freezing stress response between northern and southern adapted cultivars and surviving material from two field trial locations are discussed.
