探討番茄SlER24基因在生物逆境之重要性

Abstract

The genus Phytophthora, which belong to Oomycetes, includes many devastating plant pathogens that can infect a wide variety of crop species. Neutralized phosphorous acid (NPA) is known to be an effective control of many plant diseases caused by Oomycetes including P. parasitica. Previously it has been shown by DNA array analysis that, in response to NPA treatment, some of the tomato genes are differentially expressed, especially those involved in the ethylene-signaling pathway including SlER24. This gene is predicted to encode an ethylene-responsive transcription coactivator. Induction of SlER24 in response to NPA was further confirmed by semi-quantitative reverse transcriptase-PCR. Southern hybridization revealed the presence of a single copy of SlER24 in the genome of tomato. Analysis of the deduced amino acid sequence indicated that SlER24 contain an MBF1 domain and a helix-turn-helix domain. Phylogenetic analysis indicated that SlER24 along with AtMBF1c and pNbER24 was clustered into a group which is distinct from other tomato genes of the MBF1 family. Analysis by semi-quantitative PCR indicated that, SlER24 was up-regulated in response to heat and NPA. Moreover, it was induced when the tomato plants were inoculated with either P. parasitica or Ralstonia solanacearum. When SlER24 was overexpressed, using Potato Virus X as a vector, the plant displayed enhanced resistance against R. solanacearum, although its resistance against P. parasitica was not affected. Virus-induced gene silencing by the use of Tobacco Rattle Virus (TRV), on the other hand, indicated that down-regulation of pNbER24 caused the tobacco more susceptible to P. parasitica. These results indicated SlER24 plays a key role in plant stress response, especially the abiotic stress. However, it will need more studies to prove the interaction between tomato and stress.