DNA methylation and gene expression differences during alternative in vitro morphogenetic processes in eggplant (Solanum melongena L.)

In vitro-cultured cotyledon explants, of eggplant (Solanum melongena L.) ar e capable of producing somatic embryos or shoots, depending on which growth regulators are exogenously applied (auxins versus cytokinins). Rapidly gro wing suspension cultures were established to, model these alternative morph ogenetic processes. Clear differences in DNA methylation and gene expressio n patterns could be detected when suspension cultures grown under different growth regulator regimes were compared by restriction fragment length poly morphism. (RFLP) or Differential Display analyses. Some of the random genom ic clones showing methylation pattern differences, as well as some differen tially expressed transcripts were analyzed in detail. One of the genomic cl ones, SMG56, proved to be the first identified 1-aminocyclopropane-1-carbox ylate (ACC) synthase gene in eggplant. From 15 cloned Differential Display fragments two somatic embryogenesis (SME39, SME50), and one organogenesis ( SME88) related transcripts were identified.