Oats represents a promising alternative to small-grain cereals from Triticeae group (wheat, barley, rye) for persons suffering from any form of gluten intolerance, especially celiac disease (CD), since oat-specific prolamins avenins reveal generally lower gluten content and immunoreactivity. Recent studies on avenin molecular structure revealed large genetic variability in avenin sequences affecting the spectrum of gluten peptides produced by hydrolases in human digestive tract. The aim of the present review is to summarise recent knowledge obtained in laboratory in vitro studies focused on the effect of avenin-derived peptides on reactivity of crucial components of human immune system such as dendritic cells (DC) and T-cells. The other part of the review summarises the results of clinical studies with CD patients including oat products in their diet. Since different clinical studies revealed contradictory results regarding potential safety of oats for CD patients, the focus has to be directed at genetic variability in oat avenins. Identification of avenin isoforms with minimum CD immunoreactivity will open up ways leading to designing novel oat cultivars suitable for CD patients. Knowledge on immunoreactivity of gluten peptides together with breeding new oat cultivars revealing minimum avenin immunoreactivity with respect to CD as well as application of food processing technologies leading to gluten content reduction should result in development of gluten-free oats safe for celiacs.

Low temperatures in the autumn induce enhanced expression/relative accumulation of several cold-inducible transcripts/proteins with protective functions from Late-embryogenesis-abundant (LEA) superfamily including dehydrins. Several studies dealing with plants grown under controlled conditions revealed a correlation (significant quantitative relationship) between dehydrin transcript/protein relative accumulation and plant frost tolerance. However, to apply these results in breeding, field experiments are necessary. The aim of the review is to provide a summary of the studies dealing with the relationships between plant acquired frost tolerance and COR/LEA transcripts/proteins relative accumulation in cereals grown in controlled and in the field conditions. The impacts of cold acclimation and vernalization processes on the ability of winter-type Triticeae to accumulate COR/LEA proteins are discussed. The factors determining dehydrin relative accumulation under controlled cold acclimation treatments versus field trials during winter seasons are discussed. In conclusion, it can be stated that dehydrins could be used as suitable indicators of winter surival in field-grown winter cereals but only in plant prior to the fullfilment of vernalization requirement.

There is still an ambiguous opinion on oat regarding its safety for people with celiac disease (CD). Some studies have confirmed different content of oat immunoreactive epitopes in different cultivars while others explain the differences in consequence of cross-contamination with gluten-rich species or as ELISA cross-reactivity of oat homological epitopes with antibodies against wheat gliadin. Our study was based on a two-year mapping of oat immunoreactive epitopes in a set of 132 oat cultivars using the G12-based ELISA kit. Although repeated evaluation confirmed high interannual variability (RSD ≥ 30%) in approximately 2/3 of the cultivars, the permitted gluten content (20 mg kg-1) has not been exceeded except for contaminated cultivar Sirene. The polymorphism of purified avenins determined by SDS-PAGE revealed the occurrence of 2 bands around 30 kDa in oat cultivars with relatively high gluten content (12-16 mg kg-1) except for the cultivar Leo while this pattern occurred only in 50% oat cultivars with low gluten content. Quantification of gluten epitopes on purified avenin unit further revealed the three materials (Mojacar, Maris Oberon, SG-K 16370) with the lowest gluten content and presence of one band at 30 kDa. The band pattern at 30 kDa thus represents a promising breeding marker.