engleski

Overexpression of AtBPM1 gene in Arabidopsis confers salt and osmotic stress tolerance

MATH-BTB proteins are identified in many eukaryotes as important regulators in various biological processes, including stress responses and development. A small family of six MATH-BTB genes is present in Arabidopsis thaliana genome. They encode proteins that directly interact with and target for proteasomal degradation the class I homeobox- leucine zipper (HD-ZIP) transcription factor ATHB6 and assemble with members of the ethylene response factor/Apetala2 transcription factor family. To better understand the function of MATH-BTB proteins, we created plants overexpressing the AtBPM1-GFP fusion protein. Transgenic plants had shortened leaf petioles, rosette leaves curvature and showed premature flowering. AtBPM1-GFP recombinant protein localisation was monitored by confocal microscopy in different plant tissues during development. AtBPM1-GFP was expressed in chloroplasts, nucleus and cytoplasm during embryo development. It accumulated in the nuclei of the root stele and at lateral roots branching sites, as well as in nuclei of stomata cells. Comparative analysis in 14-day- old transgenic and wild type seedlings by qPCR revealed that overexpression of AtBPM1-GFP transgene decreased expression of other AtBPM genes. To investigate function of MATH-BTB proteins in more detail, we examined the effect of various stress stimuli on germination and growth of AtBPM1-GFP transgenic A. thaliana. When subjected to water deficit stress by mannitol, and salinity stress with NaCl and KCl, 14 day-old transgenic seedlings showed a considerable increase in tolerance compared with wild type seedlings. Furthermore, transgenic plants showed better germination and growth when subjected to elevated ABA concentrations. Our results indicate AtBPM1 regulatory role towards other MATH-BTB family members and confirmed their pivotal role in stress response and ABA signalling.

AtBPM1; overexpression; stress tolerance; Arabidopsis thaliana

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