Abstract
Cuscuta japonica, a holoparasitic plant, has neither leaf nor root. It develops a unique organ, haustorium, indispensable to parasitism. Previously, we established experimental system where haustorium production could be induced synchronously on Cuscuta seedlings even without host plants. Cytological studies using such system revealed that a part of primordial cells underwent cell death at a specific stage of haustorium differentiation. Here we report expression patterns of several genes related to programmed cell death (PCD) during haustorium development.
We extracted total RNA from haustorium-producing regions in Cuscuta seedlings, and cloned cDNAs of the PCD-related genes: 3 proteinase genes and 2 senescence-related genes. Using these and the cDNAs encoding endonuclease and 3 cell wall degrading enzymes respectively, expression pattern of each gene were monitored during the haustorium differentiation. RT-PCR analyses indicated that the seven genes showed a remarkable increase in their expression levels at the time of occurrence of the cell death.
