Phytoalexin accumulation in the roots of chickpea (Cicer arietinum L.) seedlings associated with resistance to Fusarium wilt (Fusarium oxysporum f.sp. ciceri) uri icon

abstract

  • Four chickpea cultivars which differed in their resistance to F. oxysporum f.sp. ciceris were used in histological studies of the infection process and for comparative phytochemical analysis. All the soil-grown or artificially inoculated plants that showed signs of wilting had hyphae within the root xylem. In more severe cases, a large proportion of the stem xylem vessels were also invaded by up to 5 internodes above the point of seed attachment. It is suggested that wilt symptoms may be directly caused by occlusion of the vascular tissue by hyphae. F. oxysporum f.sp. ciceris, whether present in the soil or artificially applied to chickpea roots, induced an increase in the concentration of medicarpin and maackiain in the roots, particularly in the roots of resistant cultivars. Medicarpin and maackiain showed antifungal activity to F. oxysporum f.sp. ciceris at similar concentrations to those recorded in chickpea roots. Race 2 of F. oxysporum f.sp. ciceris induced a lower level of pterocarpan biosynthesis than race 1, which was attributed to the capacity of the 2 races to induce pterocarpan biosynthesis. It is concluded that phytoalexins are important factors in Fusarium wilt resistance of chickpea

publication date

  • 1997
  • 1997