Post-acclimation transcriptome adjustment is a major factor in freezing tolerance of winter wheat

Abstract

Cold-acclimated winter wheat plants were slowly frozen to -10 degrees C, and then the temperature was either maintained at -10 degrees C or was lowered further to -12 degrees C. Expression levels of a total of 423 genes were significantly altered in these treatments; genes upregulated outnumbered those downregulated by about a 9:1 ratio. Sixty-eight genes were upregulated at least fivefold in all freezing treatments; 17 of these 68 encoded transcription factors including C-repeat binding factor (Cbf), WRKY, or other Zn-finger proteins, indicating strong upregulation of genes involved in transcription regulation. Sixteen of the 68 highly upregulated genes encoded kinases, phosphatases, calcium trafficking-related proteins, or glycosyltransferases, indicating upregulation of genes involved in signal transduction. Six genes encoding chlorophyll a/b binding-like proteins were upregulated uniquely in response to the -12 degrees C treatment, suggesting a protective role of pigment-binding proteins in freezing stress response. Most genes responded similarly in the very freezing tolerant cultivar Norstar and in the moderately freezing tolerant Tiber, but some genes responded in opposite fashion in the two cultivars. These results showed that wheat crowns actively adapt as the temperature declines to potentially damaging levels, and genetic variation for this ability exists among cultivars.

Genetic Diversity of Clinal Freezing Tolerance Variation in Winter Wheat Landraces

“…The association of SNP tag IWA7271, apparently from a gene encoding phosphatidylinositol N-acetyglucosaminyltransferase, with latitude of origin suggests that more highly-specialized membrane/lipid structures may have developed in landraces from more northerly latitudes, presumably contributing to their ability to tolerate the harsher environments. The finding of the association of freezing tolerance with an allele of SNP tag IWA1050, from a gene encoding a chlorophyll a/b binding protein, is consistent with previous findings of involvement of chlorophyll a/b binding proteins in the response of wheat plants to freezing stress [64,65]. While chlorophyll a/b binding proteins were initially discovered as part of the light-harvesting complex, recent studies have implicated these proteins in the expression of numerous traits in cereal grains, including stress responses [66][67][68][69].…”

Exposure to subfreezing temperature and a freeze-thaw cycle affect freezing tolerance of winter wheat in saturated soil

“…Herman et al (2006) demonstrated that numerous changes occur in wheat plants when incubated at −3°C. We previously demonstrated that expression levels of hundreds of genes increased significantly as isolated wheat plant crowns were cooled from 0 to −10°C (Skinner 2009), an even more severe freezing treatment than would occur in the NPF treatment in this study. A few genes significantly increased expression while the plants were held at −10°C for 1.3 h, and other genes increased expression significantly if the plants were cooled from −10 to −12°C over 1.3 h (Skinner 2009).…”

Genomics of Low-Temperature Tolerance for an Increased Sustainability of Wheat and Barley Production

“…• C after the cold acclimation, genes involved in transcription and defence processes were affected by the subzero acclimation in wheat crowns (Skinner 2009). In summary, the results of transcriptome analysis carried out with plants acclimated at various temperatures indicate that the gradual decrease in temperature during autumn triggers continuous alterations in the transcriptome pattern in order to ensure an effective adaptation to the environment.…”

“…The ability of plants to survive freezing is based on the effectiveness of cold acclimation process (Thomashow 1999;Skinner 2009). Cold acclimation is a relatively slow, adaptive response during fall, when the temperature, day length and light intensity decrease gradually.…”