Isolation and characterization of some new genes in Rye (Secale cereale L.) under Aluminum toxicity conditions

Diaa Abd El Moneim

** Department of Plant Production, (Genetic Branch), Faculty of Agricultural and Environmental Sciences, Arish University, El- Arish, 45511 Egypt.

dabdelmoniem@Aru.edu.eg

Abstract

Aluminum is the most abundant metal and the third most common element in the earth's crust. Many of the soils used for agriculture, particularly those in developing countries where forests have been cleared, are considered sufficiently acidic that they restrict the growth of many susceptible plant species. Al tolerance is an important component of an overall acid soil management strategy that will increase crop productivity on acid soils and also minimize further soil acidification. With the advent of molecular techniques, it is now possible to identify the genotypes having high level of Al tolerance at the early stage of growth, without the masking effect of the environment. Rye (Secale cereal L.) have great importance due to its broad tolerance to biotic and abiotic stress, a feature generally lacking in other temperate cereals. Compared to other cereals, rye has the best overwintering ability and the highest tolerance to drought, salt, or aluminum stress among all small-grain cereals. There are a number of potential genes which could be involved in the processes of plant defense against aluminum stress. In this study five different novel genes (MDH1, MDH2, CS, FUM and PME) were isolated and characterized. Moreover, chromosomal location has been determined. The full cDNA and genomic DNA in four different Rye cultivars (three cultivars tolerant and sensitive inbred line) were isolated. In addition, genes variability within Secale cereale, by comparing the cDNA sequences of the three cultivars tolerant and sensitive, and the variability between different species of Poaceae were investigated. To confirm the role of the studied genes in aluminum tolerance, the expression of messenger RNAs encoded by studied genes in roots and leaves for tolerant cultivar and sensitive line, produced by treatment with Al at different exposure times and different concentrations were studied. Gene expression analysis for ScMDH1, ScMDH2, ScCS and ScFUM indicate that these genes are expressed more intensely in the roots than in leaves. While in all cases, the amount of messenger RNAs is greater in tolerant cultivar than sensitive.

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Keywords: Rye (Secale cereale L.). Aluminum tolerance, Gene expression.