Exogenous application of ABA mimic 1 (AM1) improves cold stress tolerance in bermudagrass (Cynodon dactylon)

摘要

In this study, small molecules AM1, which is an ABA-mimicking ligand, was used to investigate protective effect on cold tolerance of bermudagrass. Results of phenotypic and physiological changes showed that AM1 was an effective compound to increase bermudagrass cold resistance. In contrast to the control, exogenous AM1 pretreatment significantly improved the cold tolerance of bermudagrass seedlings, including promoted growth, decreased membrane conductivity, and increased survival rate in bermudagrass seedlings under cold condition. Moreover, AM1 pretreatment reduced contents of H2O2, O (2) (center dot-) , center dot OH and malondialdehyde, and increased activities of antioxidant enzymes including glutathione peroxidase, glutathione reductase, and superoxide dismutase. Osmolyte like proline accumulated in bermudagrass after AM1 pretreatment, indicating that these substances were also involved in osmotic adjustment in bermudagrass after AM1 treatment. Gene expression analysis indicated that genes encoding antioxidant enzymes and stress inducible proteins were modulated after AM1 pre-treatment. These results showed that exogenous AM1 pretreatment significantly reduced reactive oxygen species level and increased antioxidant enzyme activity to keep the homeostasis of reactive oxygen metabolism, as well as accumulation of proline and modulation of stress inducible genes, resulting in increased cold tolerance on bermudagrass .