Ropgef Family Gene in Response to Abiotic Stresses and Expression at Different Tissues of Arabidopsis
|School||Nanjing Agricultural College|
|Keywords||Expression in tissues Cold stress Salt stress Thermal stress Osmotic stress|
Guanine nucleotide exchange factors(GEFs) convert the GDP-bound inactive form into the GTP-bound active form through GDP/GTP replacement. Through its effector domain, the GTP form interacts with specific downstream effector proteins. The mechanism of RopGEFs function in response to stress is not clear now.Arabidopsis ecotype Columbia (WT) and T-DNA-insertional knockout mutant of GEF(gef1、gef3、gef4、gef6、gef8、gef10、gefll、gef12 and gef13) were selected as experimental materials. We initially research the RopGEF family gene in response to abiotic stresses and expression at different tissues of Arabidopsis.Total RNAs were isolated from different-stage tissues of Arabidopsis ecotype Columbia for the expression of RopGEFs. Our results showed that all the RopGEFs were highly expressed in flower tissues. GEF1、GEF2、GEF3、GEF6、GEF7 and GEF14 were highly expressed in early bud, GEF4、GEF8、GEF9、GEF11、GEF12 and GEF13 were highly expressed in open flower. GEF5 and GEF10 were highly expressed in seedling. GEF1 expressed higher in young organization than in aging organization. GEF8 and GEF13 expressed higher in aging organization than in young organization. The other RopGEFs showed no difference in young organization and aging organization. GEF1、GEF2、GEF13 and GEF14 expressed higher in leaf than in root. GEF3、GEF4、GEF8 and GEF10 expressed higher in root than in leaf. But the other RopGEFs showed no difference in leaf and root.WT and gef4、gef8、gef10、,gef12、gef13 mutants seedlings were controlled at 4 degrees centigrade for cold treatment to study the phenotype. The results showed that the cold stress restrain the root growth and dry matter accumulation of gef8 and gef10. And GEF8、GEF9 and GEF10 were highly induced by cold treatment. GEF8 was first up-regulated and then down-regulated. GEF9 was always up-regulated. GEF10 was first down-regulated and then up-regulated quickly. The result explained that GEF8 and GEF10 may act as positive regulators in response to cold stress.WT and gef mutants were also treatmented by NaCl for the observation of difference in phenotype, but there were no difference in phenotype between the WT and gef1、gef3、gef4、gef6、gef8、gef10、gef11、gef12 mutants. The expression of RopGEFs were detected under salt stress. GEF3、GEF4、GEF7、GEF8、GEF9、GEF10、GEF11、GEF12 and GEF13 were highly induced by salt treatment. Perhaps a single gene loss did’t show up in the phenotype.The expression of RopGEFs were detected under thermal stress. The result showed that GEF2、GEF3、GEF6、GEF7、GEF9、GEF10 and GEF11 were highly induced by high-temperature. And the expression of RopGEFs were detected under osmotic stress. The result showed that GEF8 and GEF13 were highly induced by dehydration treatment.We can speculate that GEF7、GEF9 and GEF10 may be involved in regulating the cold, salt and thermal stress. GEF8 and GEF13 may be involved in regulating the cold, salt and osmotic stress. GEF3 and GEF11 may be involved in regulating the salt and thermal stress. GEF4 and GEF12 may be involved in regulating the cold and salt stress. GEF2 and GEF6 may be involved in regulating the thermal stress. But GEF1、GEF5 and GEF14 may do nothing in response to the four stresses.