Expression of a tomato MYB gene in transgenic tobacco increases resistance to Fusarium oxysporum and Botrytis cinerea

Abstract

MYB transcription factors play an essential role in defense responses in various plant species. Although research has investigated the function of MYB transcription factors, relative to the research progress in model plants, limited numbers of MYB transcription factors have been studied in tomato. In our previous study, transgenic tobacco plants overexpressing SpMYB increased resistance to Alternaria alternata. In the present study, some cis-acting elements associated with the environmental stresses response were observed in the promoter of this gene. SpMYB expression was significantly induced after infection with Fusarium oxysporum and Botrytis cinerea. Furthermore, transgenic tobacco plants increased resistance to F. oxysporum and B. cinerea compared with wild-type plants, and the transgenic plants had lower malonaldehyde content, but higher peroxidase, superoxide dismutase and phenylalanine ammonia-lyase activities. This resistance was also coupled with enhanced the expression of some defense-related genes (NtPOD, NtSOD and NtPAL) as well as marker genes for the jasmonic acid signaling pathway (NtPR4 and NtPDF1.2). Moreover, the transgenic plants also exhibited lower levels of H2O2 accumulation than wild-type plants following pathogen infection. Taken together, these results suggested that SpMYB positively regulates plant disease resistance; these findings will expand our knowledge on the function of tomato MYB transcription factors in defense against pathogens.