Molecular genetic studies of senescence in anthurium

Abstract

Senescence is a complex physiological process and has become an attractive area of research in plant molecular biology. The autoregulated production of cytokinin in plants transformed with the PrSAG12-IPT gene construct significantly delayed leaf senescence, and created plants that lived longer, produced more flowers with improved vase life, and an overall increased productivity. The promoter region of an arabidopsis cysteine protease served as the senescence-activated switch for the cytokinin gene IPT, and the discovery of a homolog in anthurium (ANTH17) made possible the cloning and isolation of its promoter. The sequence contained motifs and cis-elements characteristic of senescence response, and transformation of arabidopsis with PrANTH17-IPT showed similar traits with those transformed with PrSAG12-IPT. Agrobacterium-mediated transformation of anthurium with the senescence-activated gene constructs proved challenging, and stable transformation of plants was confirmed by screening for the reporter gene GFP using molecular methods. An effort to establish a protoplast transient expression system in anthurium was initiated in order to study protein subcellular signaling and localization, and is still in the process of optimization. Transcriptomic analysis of senescing leaf and spathe identified proteins involved in tissue-specific development, and provided an enormous collection of over 17,000 gene sequences that are differentially expressed. An examination of the major anthurium seed development proteins provided initial results in understanding the connection between senescence and embryo development, two very similar molecular processes in plants.