Ma. Gretenkort et Ds. Ingram, THE USE OF ERGOSTEROL AS A QUANTITATIVE MEASURE OF THE RESISTANCE OF CULTURED-TISSUES OF BRASSICA-NAPUS SSP OLEIFERA TO LEPTOSPHAERIA-MACULANS, Journal of phytopathology, 138(3), 1993, pp. 217-224
A simplified method for the quantitative assessment of the fungal lipi
d ergosterol was used to assess the levels of infection in tissue cult
ures of oilseed rape (Brassica napus ssp. oleifera) inoculated with Le
ptosphaeria maculans. The growth of L. maculans in liquid culture thro
ughout a 36-day period correlated well (r = 0.92) with the amount of e
rgosterol extracted from the mycelium. There were significant differen
ces (P < 0.05) in the amount of ergosterol extracted from infected thi
n cell layer (TCL) explants and callus tissue of two resistant and thr
ee susceptible cultivars of oilseed rape. Amounts of ergosterol extrac
ted from resistant cultivars were < 100 mug and from susceptible > 100
mug. The mean amounts of ergosterol extracted from shoot cultures of
two resistant and four susceptible cultivars were similar to those for
TCL explants and callus tissue, although the values obtained were var
iable. This technique can be used in in vitro breeding programmes to a
ccurately assess the resistance of tissue cultures of B. napus to L. m
aculans and could also have value in conventional breeding programmes.