| Agrostis stolonifera is a very important perennial cold-season turfgrass,which is widely used in urban green space and plant landscaping,and has important ornamental value and economic value.The wide variety of plant morphologies and their sessile-dominant growth patterns make the factors that determine the development of plant morphological characteristics and how plants respond to adverse environmental stresses an important direction in plant research.Biotechnological approaches to manipulate specific genes have proven to be effective strategies for crop trait modification.Abiotic stresses such as salinity,heat and drought have serious impact on plant growth and development,causing significant loss in yield and ornamental value.In order to improve the tolerance to abiotic stress,ornamental value and application range,this study transferred several genes into the plants,and studied their growth,development and abiotic stress resistance:(1)The pSBbarB-AVP1-OsSIZ1-Fld gene was transformed into creeping bentgrass by Agrobacterium-mediated genetic transformation,and the transgenic plants were studied.Transgenic plants overexpressing these three genes performed significantly better than wild type control and the transgenics expressing each individual gene under both normal and various abiotic stress conditions,exhibiting significantly enhanced plant growth and plant tolerance to drought,salinity and heat stresses as well as low nitrogen and low phosphate stress.Results suggest that AVP1,OsSIZ1 and Fld function synergistically to regulate plant development and plant stress response,leading to superior overall performance under both normal and adverse environments.(2)The CCCH-type zinc finger protein C3H12 can participate in the regulation of biotic stress in plants through the jasmine acid signaling pathway.In order to reveal the role of its last intron in plant growth and stress,the C3H12 intron C3H12-I6 was transferred into creeping bentgrass by Agrobacterium-mediated method for further study.The overexpression of C3H12-I6 in creeping bentgrass alters part of the plant growth and development characteristics and changes the tolerance of plants to drought and salt stress.Compared with wild type,the tiller number and plant height of the transgenic plants were decreased,the root length of the wild type in early growth was higher than that of transgenic plants,and the above-ground biomass of transgenic plants was higher than that of wild type;the late growth was the opposite.Transgenic plants showed enhanced tolerance to drought stress,but no significant changes in salt stress.(3)PvWRKY1,a WRKY gene from Seashore paspalum(Paspalum vaginatum),is highly expressed in an extremely salt tolerant phenotype.This gene has one highly conserved WRKY domain and the C-X5-C,HXH zinc-finger structure,which supports it should be classified to WRKY class Ⅱ.To reveal its possible role in regulating plant stress response,we have introduced PvWRKY1 into creeping bentgrass by Agrobacterium-mediated transformation.Overexpression of PvWRKY1 in creeping bentgrass alters plant development and tolerance to salinity stress.The transgenic plants shown much less tiller number than wildtype and no significant changes in salt stress,although it was highly induced by salinity treatment in seashore paspalum.The information obtained in this study provides new insights into gene stacking,introns,and transcription factors as efficient methods for genetic engineering of plants.Similar strategies can be extended to other crop species for trait modification.Further characterization of transgenic plants helps to a better understanding of the molecular mechanisms of different genes involved in plant development and stress response,and provides information for the development of novel biotechnological approaches for genetic improvement of crops,thereby increasing their agricultural yield and ornamental value. |
