Molecular cloning and characterization of a Late Embryogenesis Abundant 14 (IbLEA14) from dehydration-treated fibrous roots of sweetpotato

摘要

A new late embryogenesis abundant 14 (LEA14) cDNA was isolated from ESTs library of dehydration-treated sweetpotato (Ipomoea batatas) fibrous roots. A search of the protein BLAST database revealed that this protein can be classified as a LEA14 protein. Analyses of quantitative RT-PCR revealed diverse expression patterns of the IbLEA 14 gene under different stress conditions. The IbLEA 14 transcript level was strongly induced by dehydration, NaCI and abscisic acid treatments. Therefore, to understand roles of IbLEA14 under stress conditions, transgenic sweetpotato non-embryogenic callus which contained IbLEA14 overxpression or RNAi vectors under the control of CaMV 35S promoter were generated. The integration and gene expression levels of the transgenic callus were confirmed via analysis of genomic PCR,quantitative RT-PCR and western blot analysis.IbLEA14 overexpressing transgenic callus showed enhanced tolerance to drought and salt stress, whereas RNAi callus exhibited increased stress sensitivity.In addition,Iignin contents increased in the IbLEA14 overexpressing callus under normal culture conditions. These results suggest that the expression of IbLEA 14 in the transgenic callus may function as a positive defense role in the drought and salt stress response.