Function Analysis Of Tomato Gene JERFs

By yeast one-hybrid screening, four genes have been previously isolated from a tomato cDNA library. Sequence analysis suggests that all the 4 genes have a high conserved DNA binding domain-AP2 domain, similar to transcription factor ERF. And further investigations indicate that all the 4 genes can bind to jasmonate and ethylene response element and activate GCC box-containing report gene transcription in yeast and targete to the nucleus, therefore these genes were named as JERF10, JERF26, JERF33, JERF36.In order to understand these genes' regulating functions in plants, the constructs of over-expression and anti-expression containing JERFs respectively were first generated using pROK2. After confirmation by PCR , the constructs were introduced into tobacco and tomato by Agrobacterium infiltration respectively. After PCR identifications, 27 lines ofJERFJO, JERF26, JERF33, JERF36 for overexpression transgenic tobacco and 20 lines of JERF10, JERF26, JERF33 for antisense transgenic tomato are got. The assays of segregation indicates that line 4 of JERF33 shows 3:1 ratio in Tl seedlings. Also there is a significant change in its leaves in line 4 and 5 of JERF33. And this phenotype is similar to that observed in plants treated with ethylene, indicating that the JERF33 is involved in the regulation of a subset of ethylene-responsive genes containing GCC box. By using this line of JERF33-4, the further tests were conducted. Our results indicate that some PR genes containing GCC box such as Osmotin, prb~lb et al were expressed in unstressed transgenic tobacco plant, but not detected in unstressed wild tobaccos, suggesting that JERF33 could act as a transcriptional activator to regulate expression of GCC box-containing genes. Furthermore, the overexpression transgenic tobaccos demonstrate more tolerance to freezing and dehydration and dwarfed phenotypes which were found in plants overexpressing some DREB transcriptional factors. All these results suggest that the JERF33 might be involved in two separate signal transduction pathways under abiotic and biotic stress as a positive trans_acting factor.