Aluminium ToleranceBioinformaticsBoron ToleranceChickpea GenomicsDrought ToleranceDrought Forward GeneticsDrought Reverse GeneticsFrost ToleranceGenome AnalysisHybrid wheatIron BiofortificationMetabolomics and ProteomicsNitrogen Use EfficiencyP and Zn Use EfficiencyPlant TransformationSalinity ToleranceStructural BiologyScientific PublicationsACPFG Front Covers Exhibition
Under acidic (pH less than 5.0) conditions, the phytotoxic aluminum cation (Al3+) is released into the soil solution where it can damage plant roots, hampering their ability to acquire water and nutrients. Over a half of the world's arable land is acidic. Consequently, soil acidity and associated aluminum toxicity poses a major limitation to agricultural production worldwide. In Australia alone, Al toxicity affects 1.5 million hectares of cropping land and causes yield losses worth around $180 million annually. A common mechanism of Al tolerance in plants is the release of Al binding organic acids such as malate and citrate from the root tips. Al tolerance genes have been shown to encode ALMT1 or MATE transporters which facilitate this organic acid release. Rye is one of the most Al tolerant of all the cultivated cereals and provides the main focus for our studies.
Effect of aluminum toxicity on tolerant and intolerant rye varieties. Aluminum mainly damages the tips of the roots. The plants were stained with a dye shortly after treating with toxic aluminum, then allowed to resume growth under non-toxic conditions. Only the tolerant plants containing the Alt4 gene resumed root growth beyond the stained region.
Positional cloning identified a cluster of ALMT1 genes controlling Al tolerance at the Alt4 Al tolerance locus of rye. ALMT1 expression patterns were examined by quantitative real-time PCR. A large-insert (BAC) library of an Al tolerant rye is available at ACPFG to facilitate sequencing of Alt4 locus. Function of ALMT1 genes will be explored by monitoring tolerance and organic secretion from roots of recombinant or transgenic plants, and by electrophysiology experiments in frog eggs. ALMT1 structure will be explored by modelling and analysis of purified proteins by a variety of methods.
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