Characterization of Aspergillus niger B-1 RNase and its inhibitory effect on pollen germination and pollen tube growth in selected tree fruit.

摘要

Aspergillus niger B-1 (CMI CC 324626) extracellular ribonuclease (RNase B1) was purified to homogeneity. It was found to contain two isoforms of 32- and 40-kDa glycoproteins, sharing a 29-kDa protein moiety. Optimal RNase activity was observed at 60oC and pH 3.5. In 'Almog' peach (Prunus persica) and 'Murcott' tangerine (Citrus reticulata), the enzyme inhibited pollen germination and pollen tube growth in vitro as well as in vivo. In field experiments at Rosh Zurim, Israel in April 1994, spray application of the RNase caused a reduction in 'Fantasia' nectarine (Prunus persica) fruit set and interfered with embryo development. The biological effect of the RNase may be of horticultural value, due to its potential to control fertilization.