PHYTOPATHOLOGICAL CHEMISTRY OF SWEET-POTATO WITH BLACK ROT AND INJURY .134. BIOSYNTHETIC CORRELATION OF VARIOUS PHYTOALEXINS IN SWEET-POTATO ROOT-TISSUE INFECTED BY CERATOCYSTIS-FIMBRIATA

In sweet potato root tissue infected by Ceratocystis fimbriata, changes in a one hourincorporation of radioactivities from 2-14C-acetate into furano-terpene phytoalexins were examined during incubation. The data showed that radioactivities in the CHCl3 fractions (containing lipid) were increased after 15 hr of incubation, and were found in furano-terpenes as visualized by the TLC radioautograms. Pulse and chase feeding of 2-14C-acetate at low temperature was also performed using tissue discs incubated for 36 hr with the infected region. Changes in the radioactivities of the individual components were investigated with TLC. Several components such as OHDHMy were labeled rapidly, then followed a decrease in the label. These changes were accompanied by increases in the radioactivities of other components such as DHIp, Ip, IpOH and Component B1. These results are further evidence for the hypothetical pathway that has been proposed previously, with some modifications. © 1979 Oxford University Press.