Expansin proteins play a role in regulating cell growth and plant adaptation to various environmental stresses. The objectives of this study were to clone and characterize the expression and promoter activity of a gene in creeping bentgrass (Agrostis stolonifera L.) encoding an expansin protein, AsEXP1, in response to heat stress and plant hormones. The AsEXP1 cloned from the genome of heat-tolerant genotype 'Penn A-4' spans a 2659 bp DNA sequence and consists of three coding sequences, two introns, a 962 bp 5'-noncoding region, and a 483 bp 3'-noncoding region. Several putative abscisic acid (ABA)-response cis-elements and gibberellic acid (GA)-response cis-elements were found nearby TATA box in the promoter region through the search of PlantCARE database and PLACE database search. AsEXP1 transcripts were detected by reverse transcription polymerase chain reaction (RT-PCR) in Penn A-4 leaves treated with ABA and GA, while no transcripts were detected in untreated plants. The AsEXP1 promoter was cloned into a binary vector fused to a β-glucuronidase (GUS) marker gene (pAsEXP1-GUS) and introduced into rice (Oryza sativa L.) callus ('Kassalatha'). Reverse transcription polymerase chain reaction confi rmed that the expression of pAsEXP1 in A. stolonifera was inducible by heat stress and exogenous applications of GA and ABA. Our results demonstrate that the AsEXP1 gene may be involved in the signal pathway of hormone regulation of plant responses to heat stress.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science