Cloning And Functional Analysis Of Rice OsSZF1 Gene

Rice is one of the three main grain crops in the world. Thus, it is important toenhance the research and breeding on rice with nice characters. It was a landmark whenthe rice genome was completely sequenced. So human can take a close look at themolecular level of rice and makes it easier for researcher. China is in short of water.Though tremendous works have been done in plant mechanisms of drought stress atphysiological, biochemical and molecular levels and a number of drough related geneshave been cloned so far, it's mechanism is still unclear. The resistance of plants to droughtstress is controlled by multiple genes of the complex quantitative traits and is affected byplant species, genotypes, characters and internal physiological and biochemical reactions.In order to characterize genes suitable for plant breeding, we have employed thepopular variety, Huhan 3, as a model rice plant for studying the mechanisms of ricedrought resistance. On the basis of our previous work on rice drought QTL analysis. UsingRT-PCR method, we have cloned a conserved region of ring zince finger family which arelocated in rice drought QTL interval. And obtained OsSZF1 3'- and 5'- end fragments byRACE technology. We used Vector NTI 8.0 to combine conserved region, 3' and 5'sequences then obtained OsSZF1 full length cDNA. Using bioinformatics tools we foundOsSZF1 gene had high similarity to Ring zinc finger family, one open reading frame,encode 367 amino acids, and both 3' and 5' end had no-coding regions. Southern blotanalysis showed rice only contained one copy OsSZF1 gene. Quantitative PCR showedOsSZF1 gene was up-regulated by NaCl,abscisic acid (ABA),mannitol treatment.Interestingly, salicylic acid (SA) and methyl jasmonate acid (m-JA) enhanced graduallyOsSZF1 expression all along low consistence treatment. But its expression was allinitiated down-regulated when the consistence went up. All this showed rice geneOsSZF1 is related to rice abiotic stress. Finally, a plant expressing vectorpCAMBIA2300-OsSZF1 was constructed to transform dicot plant. The recombinantvector was subsequently introduced into Agrobacterium tumefaciens with freeze-thawmethod. The leaf discs of tobacco plants were infected by A. tumefacienskanamycin-resistant plants were regenerated on the selection medium containingkanamyxin. PCR and Southern blot analyzes confirmed that the OsSZF1 gene wasintegrated into transgenic tobacco genome. And also only one copy in the tobaccogenome. In order to make sure whether gene OsSZF1 have activation domain or not, weconstructed yeast expression vectors and want to do experiments in future.