Proline Accumulation in Peppers (Capsicum annuum L.) Resistant and Susceptible to Root Rot (Phytophthora capsici Leon.)

Authors: Işıl ÖNCEL, Ayşen Sülün ÜSTÜN, Yüksel KELEŞ

Abstract: During the seedling period (7-8 leaves) susceptible (Ince Sivri-35) and resistant [PM 217, PM 702 (=CM 334)] pepper genotypes to Phytophthora capsici Leon. were inoculated with Antalya isolate of P. capsici Leon. (104 zoospores/ml) to examine the effects of proline accumulation in roots, stems and leaves. It was observed that the proline content in, both upper and lower leaves of infected susceptible genotypes increased with time. In the upper and lower leaves of infected seedlings of PM 217 genotype proline content decreased towards the sixth day, the whereas proline content didnÕt change any more in the upper and lower leaves of PM 702. Excess proline was observed at the top of the stems of infected seedlings where infection reached late. In susceptible genotype, proline content increased with time, but in two resistant genotypes a decrease was observed until the fourth day. On the sixth day the decrease continued in PM 217, but an increase was observed in PM 702. As a result, the proline amount decreased in infected I. S-35 roots, where it was near the control group in PM 217 and more proline accumulation was observed in PM 702. It was observed that in the roots, stems (lower-middle-upper) and leaves (lower-upper) of the control groups susceptible genotypes accumulated less proline than did resistant genotypes.

Keywords: Solanaceae, Pepper, Phytophthora, Root rot, Proline.