| We isolated a resistance rice mutant from indica cultivar of rice (Oryza sativa L. cv. Kasalath) with EMS mutagenesis regeneration. Physiological indexes were investigated, the results indicated that the mutant was more resistance to aluminum. However, the detection of Al in root apices with ICP and hematoxylin staining of roots show no distinct Al content difference in root apex between Kasalath and mutant. QRT-PCR analysis of genes expression profiles in root apices show that aluminum resistance relative genes in rice, such as Nratl and STAR2, up-regulated under aluminum stress in both Kasalath and mutant, the mutant even higher. Although the exact mechanisms for high resistance in rice have not been elucidated, it is clear that multiple physiological aspects participated in the detoxification of aluminum. Genetic analysis of F1 populations show that aluminum resistances was as low as Kasalath, while sensitive compare to mutant. These results indicated the high resistance was probably controlled by a single recessive gene.Cell wall components display different adsorption ability for aluminum. After extraction of pectin, aluminum adsorption of the rest fraction was not significantly reduced. These results suggested that pectin may play an important role in protect the sites that can combine with aluminum exist in hemicellulose, which maybe one of the key points that aluminum induced inhibition of root growth. Uronic acid content of pectin and hemicellulose fraction was reduced after the aluminum stress. While galactose and arabinose in pectin increased, which were important component of RGI. Localization of galactan and arabinan by monoclonal antibodies LM5 and LM6, immunofluorescence revealed that Al treatment resulted in increased of both these two side chains. RGI side chains play important role in physicochemical properties. These results indicated that Al-induced increasing of side chains is possibly involved in the Al-induced root growth inhibition.
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