Expression of antiapoptotic genes bcl-xL and ced-9 in tomato enhances tolerance to viral-induced necrosis and abiotic stress

Ping Xu, Stephanie J Rogers, Marilyn J Roossinck

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D satellite RNA (satRNA) is a strain of cucumber mosaic virus (CMV) satRNA that induces an epidemic lethal disease in tomato. No natural resistance or tolerance has ever been found. Previously, we demonstrated the involvement of programmed cell death in disease development. Here, transgenic tomato plants expressing animal antiapoptotic genes bcl-xL and ced-9 were generated through agrobacterium-mediated transformation. High expression of bcl-xL or ced-9 affected plant growth and seed development. Inoculation of seedlings with CMV/D satRNA at T(1) and T(2) generations resulted in delayed cell-death symptoms or absence of symptoms. The degree of symptom suppression was correlated with increasing expression levels of the transgenes. Survival rates were compared among inoculated transgenic lines expressing bcl-xL, ced-9, and bcl-xL (G138A), a loss-of-function mutant of bcl-xL. More than 80% of the bcl-xL and ced-9 T(1) transgenic lines showed higher survival rates than the average for bcl-xL (G138A) transgenic lines. Total RNA extracted from surviving plants contained D satRNA, indicating systemic accumulation of D satRNA. Thus, expression of bcl-xL and ced-9 improved tolerance to, rather than resistance to, CMV/D satRNA infection. In addition, expression of bcl-xL and ced-9 specifically abrogated the formation of necrotic lesions, but not other symptoms, in tomato leaves during chilling at 4 degrees C. At 7 degrees C, temperature-induced leaf senescence was dramatically delayed in bcl-xL and ced-9 transgenic plants, and high levels of anthocyanins accumulated, possibly limiting oxidative stress. Hence, expression of these animal antiapoptotic genes improved plant survival under abiotic or biotic stress.

Original languageEnglish
Pages (from-to)15805-15810
Number of pages6
JournalProceedings of the National Academy of Sciences
Issue number44
Publication statusPublished - 2 Nov 2004
Externally publishedYes


  • Agrobacterium tumefaciens
  • Animals
  • Apoptosis
  • Apoptosis Regulatory Proteins
  • Base Sequence
  • Caenorhabditis elegans Proteins
  • Cucumber Mosaic Virus Satellite
  • Cucumovirus
  • Viral DNA
  • Lycopersicon esculentum
  • Plant Diseases
  • Plants, Genetically Modified
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Genetic Transformation
  • bcl-X Protein

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