Expression Pattern of Genes Related to Shoot Apical Meristem Formation during Haustorium Development in a Holoparasitic Plant, Cuscuta japonica

Abstract

Cuscuta japonica is a holoparasitic plant which develops a haustorium, a unique organ for absorption of nutrients and water from the host plant. The haustorium formation is initiated by emergence of meristematic cells in the cortex of Cuscuta stem. Then, the meristematic cells differentiate into haustorium. During such process, several genes related to shoot apical meristem formation are expressed. However, the mechanism involved in de novo formation and maintenance of haustorium meristematic cells has been poorly understood in Cuscuta. In this study, we isolated Cuscuta homologues of the genes for adventitious bud differentiation and shoot meristem maintenance in Arabidopsis thaliana, e.g. CUP-SHAPED COTYLEDON2, WUSCHEL and CLAVATA1. Their expression patterns during haustorium development were analyzed by RT-PCR. The role of their genes in haustorium formation in Cuscuta will be discussed.