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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Crop Improvement and Genetics Research » Research » Publications at this Location » Publication #344199

Title: Transcriptomic insights into phenological development and cold tolerance of wheat grown in the field

item QIANG, LI - University Of Saskatchewan
item BROOK, BYRNS - University Of Saskatchewan
item BANIRE-DIALLO, ABDOULAYE - University Of Quebec
item DANYLYK, JEAN - University Of Quebec
item SARHAN, FATHEY - University Of Quebec
item BADAWI, MOHAMED - University Of Quebec
item L Chingcuanco, Debbie
item ZOU, JITAO - National Research Council - Canada
item FOWLER, BRIAN - University Of Saskatchewan

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2017
Publication Date: 3/1/2018
Citation: Qiang, L., Brook, B., Banire-Diallo, A., Danylyk, J., Sarhan, F., Badawi, M.Y., Chingcuanco, D.L., Zou, J., Fowler, B. 2018. Transcriptomic insights into phenological development and cold tolerance of wheat grown in the field. Plant Physiology. 176:2367-2394.

Interpretive Summary: To understand how some plants are able to survive winter, we compared the expression of genes in field-grown cold-sensitive Manitou and cold-hardy Norstar wheat plants. We monitored gene expression in crown tissues differing in vernalization requirements and potential cold tolerance for two years at five timepoints from early autumn to winter. The results revealed several of the low temperature (LT) tolerance strategies that wheat has evolved to optimize autumn seedling growth and development in preparation for a wide range of LT challenges. This analysis also permitted us to assess the environmental sensing mechanisms that allow wheat plants to anticipate and prepare for increased cold stress and, in extreme cases, severe winter conditions. Not only were plants able to anticipate and prepare for cold stress, but they made these complex adjustments while experiencing the very different weather patterns that prevailed during the two autumns of this study. In-depth analysis of gene expression revealed a complex interplay among and changes in different biological pathways in response to cold. Cold tolerant plants tended to delay flowering, which allowed longer time for the plants to express genes needed for protection against low temperatures. Cold tolerant plants expressed several dehydrins and other cold induced proteins at higher levels than the cold sensitive plants. The use of genetic lines that differed in the vernalization requirement gene that controls flowering, Vrn-A1, allowed us to separate genes that respond to differences in flowering time from those that are needed for cold acclimation. We also uncovered the critical roles played by two wheat chromosomes, 6A and 6D, in the expression of spring and winter growth habit and LT tolerance. Overall, our results demonstrate the complexity of the genetic systems involved in the interplay of development and LT tolerance in bread wheats.

Technical Abstract: Low temperature (LT) acclimation and winter survival in cereal species is determined by complicated environmentally regulated gene expression. However, studies investigating these complex LT responses are mostly conducted in controlled environments that only consider the responses to single environmental variables. In this study, we have comprehensively profiled global transcriptional responses in crowns of field-grown spring and winter wheat genotypes and their near isogenic lines (NILs) with their VRN-A1 alleles exchanged. This in-depth analysis revealed highly complex, multiple signaling, interactive pathways that influence LT tolerance and phenological development to adapt plant growth and development in preparation for a wide range of over-winter stresses. Investigation of genetic differences at the VRN-A1 locus revealed that a vernalization requirement maintained a higher level of LT response pathways while VRN-A1 genetically promoted floral development. Our results also demonstrated that genetic background has a large influence on the expression of cold and flowering pathways. The link between delayed shoot apex development and the induction of cold tolerance was reflected by the gradual up-regulation of ABA-dependent and CBF pathways. This was accompanied by the down-regulation of key genes involved in meristem development as the autumn progressed. The locations of genes differentially expressed between winter and spring wheat genetic backgrounds showed a striking bias toward those on chromosomes 6A and 6D, indicating transcriptional regulation at the subgenome level. This finding adds new insights into the complexity of the gene expression cascades and their interactions that determine phenological development and LT tolerance.