Isolation Of Salt Tolerant Mutants Of Arabidopsis And Further Research On Related Genes

Salinity greatly limits plant growth and crop productivity and poses an increasingly serious threat to the sustainability of agriculture. As a consequence, unremitting effort has been conducted to determine the adaptive mechanisms that plants have evolved to survive this abiotic stress. Salt tolerance mechanisms in plants are very complex and involve multiple parallel and interacting pathways.Here, we reported two mutants that can germinate at 200 mM NaCl and designed as AT6 and AT13, respectively. AT6, a KO mutant of AT1g73660 exhibits salt tolerance phenotype during germination and seedling growth. AT1g73660 encodes a protein with similarity to Raf-like MAPKKKs. No difference in germination was observed between the mutants and the wildtype during the sensitivity assay to ABA, GA or ACC. Taken together, our results showed that AT1g73660 negatively regulated salt tolerance.Cloning of the chromosomal DNA flanking the T-DNA in AT13 mutant revealed that the insertion had caused a knockout mutation in the gene AT3g58110. To confirm the gene-to-trait relationship of AT13 mutant, germination frequency of two other mutant alleles was observed in the presence of NaCl and ABA. All these assays showed that gene AT3g58110 negatively regulated the salt regulation of seed germination via the ABA pathway in Arabidopsis. In addition, the late-flowering phenotype and dark green leaves implied that the gene AT3g58110 product was also a regulator of plant development.