Aluminum toxicity in plants, understanding responses to aluminum in sensitive and tolerant rye genotypes

Aluminum (Al) is an important toxic heavy metal, considerable reducing plant growth and crop production, in particular in acidic soils, worldwide. Rye (Secale cereale), is a crop particularly known for its tolerance to acidic soils, and to Al. Therefore, understanding the Al-tolerance mechanism, at the molecular, mechanistic level, will provide a basis for tolerance-improvement, also for other crops. Previously (3 years PhD work by the candidate), two rye genotypes were used, Beira and RioDeva, respectively more tolerant and more sensitive to Al, to unravel the underlying molecular mechanisms. Young rye plants were exposed to sub-lethal doses of Al, for short periods of time (24, 48h), and analyzed at multiple organizational levels. Analyses included photosynthesis, antioxidant metabolism, and several other defense responses. The analysis demonstrates that there are differences at the molecular level, between the genotypes, and differences in response to Al, at the level of defense responses. This work has been performed by the candidate at the University of Porto in collaboration with the IMPRES group at the University of Antwerp.The aim of the DocPro-project, is to deepen the understanding of Al-tolerance in rye, by expanding on the results obtained so far, with expertise at the University of Antwerp (IMPRES laboratory, prof. H. Asard & prof. G. Beemster). The specific objectives of this project are 1) the identification of the cellular basis of the growth response in the leaf growth zone (i.e. meristematic zone and elongation zone), through kinematic growth analysis. This identification will be used to analyze, zone-specific, biochemical and molecular responses to Al. And 2), a genome-wide transcriptome-level analysis (through Next Generation Sequencing) of the Al-response in each genotype. This will result in identification of molecular responses to Al that mediate the whole organ growth response, and which will be of interest for future basic and applied research.The overall work on Al toxicity by the candidate, is novel in that it focusses on acute Al toxicity in rye seedlings, and applies genotype-comparison to unravel tolerance mechanisms.Two elements contribute to guaranteeing the successful outcome of this project, i.e. 1) the work performed so far (in Portugal) will result in 3 publications (A1), and, by itself, could be sufficient to obtain a PhD at the home institution. 2) the expertise of the IMPRES laboratory, fits seamless to the previous work of the candidate, and is a natural extension that will result in a joint PhD and an additional high-impact publication.

Keywords:PLANT STRESS PHYSIOLOGY, TRANSCRIPTOMICS, PLANT BIOCHEMISTRY, HEAVY METALS

Disciplines:General biology, Plant biology