Characterization of transgenic tall rescue expressing an ABA-inducible transcription factor

摘要

Abscisic acid (ABA) dependent gene activation pathway is mediated by a specific subfamily of basic leucine zipper (bZIP) transcription factors that recognize abscisic acid responsive elements (ABREs), known as ABRE binding factors (ABFs).ABFs are known to confer drought tolerance in several model plant species where as only few reports have been found in forage crops in term of stress tolerance.The leaf and stem are the main parts of forage crops, determines forage quality and quantity, affected by several abiotic stresses.ABA-responsive gene in model plants have been shown to confer tolerance to multiple stresses including chilling, freezing, high temperature, drought and oxidative stresses.Therefore, ABA-responsive gene might be useful to genetically engineer tall fescue plants in multiple stress tolerance.The aim of the study was to transfer ABA-inducible gene in tall fescue plants and check their performance against abiotic stress tolerance.In the present study, we obtained transgenic tall fescue plants with an ABA-responsive gene.Genomic PCR and Southern blot analyses showed that transgene was stably integrated into the plant genome.The induction of ABF expression in transgenic tall fescue under drought stress (limited irrigation) was confirmed by RT-PCR and RNA gel blot analyses.Transgenic plants exhibited better growth performance compared to wild type under drought stress.The enhanced drought tolerance of the transgenic plants could be attributed to their lower transpiration rates.These results suggest that overexpression of ABA-responsive gene in tall fescue might efficiently modulated drought stress protection mechanisms in tall fescue under environmental stresses.