African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12496

Full Length Research Paper

Tolerance of banana for fusarium wilt is associated with early H2O2 accumulation in the roots

  Wei-Ming Li1, Chun-Mei Qian2, Yi-Wei Mo1, Yu-Lin Hu1 and Jiang-Hui Xie1*
    1South Subtropical Crops Reserch Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang China, 524091. 2College of Lifescience, South China Agricultural University, Guangzhou, China, 510642.    
Email: [email protected]

  •  Accepted: 21 July 2011
  •  Published: 21 September 2011

Abstract

 

Banana plants derived from a tissue culture process possess a high rate of random variations that were widely used as popular cultivars due to the new desired traits. In this study, two near-isogenic lines, one susceptible (parental Williams-8818) and the other resistant (somaclonal variation progeny Williams-8818-1 from Williams-8818) to Fusarium oxysporum f. sp. Cubense (Foc4), were inoculated with race 4 of F. oxysporum (Fox). Production of O2•− , H2O2 and MDA, as well as changes in enzyme activities, and transcript levels of SOD and CAT in root extracts were monitored every 24 h over 4 days. The histochemical location of H2Owas also detected. In the resistant iso-line, the accumulation of O2•− and H2O2, and the activation of SOD occurred in the first 24 h, but activation of CAT reached its maximum only after 48 h. All changes were generally lower in the susceptible iso-line when compared to the resistant iso-line. SOD transcripts were further up-regulated until 72 h in the resistant iso-line, but not in the susceptible iso-line. CAT expression was not affected in any of the two iso-lines. This suggests that expressions of the two key genes in the antioxidant system are less suitable indicators for Foc resistance in banana. In contrast, the first “oxidative burst” is a better indicator for different susceptibility of banana to Foc.

 

Key words: Banana, Fusarium oxysporum, catalase, reactive oxygen species, somaclonal variation, disease resistance.