Biochemical, physiological and genetic analysis of aluminum tolerance of different rye species

Aluminum (Al) toxicity is the major limitation for crop productivity in acid soils which are widespread all overthe world. Plant species differ in their responses to this abiotic stress having developed resistance mechanisms todetoxify and tolerate Al both internally and externally. Rye (Secale cerealeL.) is one of the most Al-tolerant cerealwith a valuable genetic background for breeding purposes. Wild relatives (Secalespp.) have great importanceonce they can provide new sources of genes related to this trait. Different cellular disorders possibly related to Altolerance/toxicity were observed through histochemical root staining methods in cultivated and wild ryes and acorrelation was found. Moreover, expression studies of seven candidate Al-tolerance genes (ScALMT1,ScMATE2,ScSTOP1,ScMDH1,ScMDH2,ScCu/ZnSODandScMnSOD) were performed in roots and shoots offive wild ryes.All genes seems to have an active contribution on Al resistance mechanisms of these ryes, however,ScALMT1andScMATE2genes clearly have a key role in the Al-tolerance increment. Al tolerance inSecalegenus seems tobe a genetically complex trait where different resistance mechanisms coexist, due to several genes whose cu-mulative effects improves the ability to withstand Al phytotoxicit