Brachypodium distachyon is considered a powerful model system to study the response of temperate cereals to adverse environmental conditions. Colton-Gagnon et al. examine cold acclimation and freezing tolerance in seven diploid accessions, and find that cold treatment accelerates the transition from the vegetative to the reproductive phase in all of them. This is associated with the gradual accumulation of BradiVRN1 transcripts, and the accessions exhibit a clear cold acclimation response by progressively accumulating proline, sugars and COR gene transcripts. However, whole-plant freezing tests show that the accessions only have a limited capacity to develop freezing tolerance when compared to winter varieties of temperate cereals such as wheat and barley. Furthermore, little difference in terms of survival is observed among the accessions tested despite their previous classification as either spring or winter genotypes.
There are a number of well-developed Agrobacterium-mediated transformation methods for dicotyledonous plants, but few for monocotyledonous plants. Fursova et al. develop a new approach for transient gene expression in the grass, Brachypodium distachyon, using co-cultivation of mature seeds with bacterial cells, and including leaf extract of Nicotiana tabacum and acetosyringone. Expressed proteins are directed to a plant apoplast, where they maintain hydrolytic activity and alter cell wall composition and biomass digestibility. This newly developed approach provides a quick and efficient technique for expressing genes of interest in Brachypodium.
The model grass species Brachypodium distachyon has three cytotypes that are currently regarded as part of a single species. Catalán et al. combine analysis of phenotypic traits with multiple cytogenetic analyses and detect significant differences between the cytotypes and demonstrate stability of characters in natural populations. Genome size estimations, GISH, FISH and CCP confirm that the 2n = 10 and 2n = 20 cytotypes represent two different diploid taxa, whereas the 2n = 30 cytotype represents a derived allotetraploid from them. They keep the name B. distachyon for the 2n = 10 cytotype, and describe two novel species as B. stacei for the 2n = 20 and B. hybridum for the 2n = 30 cytotypes.
The Yellow Stripe-Like (YSL) family of proteins are transporters of metal-phytosiderophore and metal-nicotianamine complexes. Information concerning their physiological role(s) is critical for understanding metal homeostasis on the whole-plant level. By comparative genomics analysis of the YSL family from Brachypodium distachyon, maize and rice, Yordem et al. establish the existence of a highly conserved clade within the YSL family that is unique to grasses. The expression pattern of many of the brachypodium YSL genes is regulated by the iron status of the plant, thus confirming their probable roles in iron homeostasis mechanisms.