Arabidopsis tanmei/emb2757 embryo mutant is defective for in vitro plant morphogenesis

Abstract

A mutation in the Arabidopsis TANMEI/EMB2757 (TAN) gene with an embryo defective phenotype was analysed for its effect on the morphogenic potential of somatic tissue cultured under in vitro conditions. The capacity for in vitro morphogenesis was evaluated using cultures of immature zygotic embryos, and seedling explants of the tan mutant and the parental Col-0 genotype. The explants were cultured on media supplemented with different plant growth regulators, and the capacity for two alternative pathways of morphogenesis, somatic embryogenesis (SE) and shoot organogenesis, was evaluated. Reporter genes (GUS, GFP) were used to monitor auxin and LEC2 and FUS3 gene activity in the tan explants. Moreover, the expression pattern of the TAN gene was analyzed during SE and in callus tissue of Col-0. It was indicated that the tan mutation resulted in a total lost of embryogenic and organogenic capacity of cultured tissues, suggesting the involvement of the TAN gene in basic cellular processes related to cell growth and differentiation. However, differential expression of the TAN gene during SE, and its increased activity at advanced stages of embryogenesis, implicate a specific role for the gene in the development of somatic embryos.