Function Identification Of A Novel CCCH-type Zinc Finger Protein GhZFP1 In Cotton And Pilot Study Of Function Of The SRZFP Subfamily Protein In Arabidopsis

High salinity and fungal attack are major stresses that are commonly encountered in plants during their developments. Upon exposure to the environmental changes, many genes in plants are induced and their products either directly protect plants against stresses or further control the expression of other target genes to eliminate or alleviate the physiological damages. To understand the adaptive mechanisms of plants, it is necessary to know the function of crucial genes and their regulation during different stress responses in plants。Zinc finger proteins are defined as a superfamily with typical zinc finger domain that involved in many aspects of plant growth and development. Some zinc finger protein related to stress have been isolated and identified. However, a few of CCCH-type zinc finger proteins have been studied. In this study, a new zinc finger gene GhZFP1 related to salt stress was identified by differential hybridization screening previously. The main results are as follows:1. The transgenic tobacco plants overexpressing GhZFP1 grew better than wild type tobacco in 200 and 300 mM NaCl conditions, and then further verified by measuring changes in chlorophyll fluorescence (Fv/Fm) or endogenous Na+, K+ contents in shoots and roots , thereby validating the increased tolerance to salt stress. The enhanced resistance to Rhizoctonia solani in transgenic tobacco also demonstrated that disease resistance conferred by GhZFP1 was effective against fungal pathogens.2. We screened and identified 9 positive clones that interacting with GhZFP1 by using yeast two-hybrid screening.The result of the YFP Bimolecular fluorescence complementation (BiFC) indicated that GhZFP1 interacted with GZIRD21A or GZIPR5. Northern blot analysis showed that expression of GZIRD21A was very rapidly induced by PEG and SA treatments, and GZIPR5 transcripts were induced by NaCl and SA treatments in cotton. These results were resembled to the expression of GhZFP1, indicating that their interaction help to facilitates formation of higher order complexes to play important roles.3. Interaction sites analysis of GhZFP1 suggested that it interacted with GZIRD21A and GZIPR5 by different amino acid sequences, To investigate the smallest binding sites of GZIRD21A and GZIPR5 in GhZFP1, a series deletions of GhZFP1 were need to be generated in the future study.4. The microarray date from Genevestigator site and the result of RT-PCR showed that the expression of the subfamily genes changed under stresses stimuli. The promoter analysis of it's three mumbers showed that there were some differences between them. Germination experiments indicated that AT2G19810 might play a negative role in the germination in salt stress.