Transferring SSR Markers Across Genus for Caladium Breeding and Genetic Analysis

Molecular markers have become a valuable tool for plant breeding and genetic research.  Due to a number of their characteristics, including being rich in plant genomes, hyper-variable among species/cultivars, co-dominant between alleles, and transportable from laboratory to laboratory, SSR (simple sequence repeat) markers have become the choice of molecular markers to be used in many breeding and genetic applications.  So far, no SSR markers have been reported (or developed) for caladium (Caladium × hortulanum), a versatile pot/bedding plant and a representative of a large group of ornamental aroids including aglaonema, anthurium, calla lily, dieffenbachia, spathiphyllun, etc.  To identify SSR markers that can be used in caladium breeding and genetic analysis, we have attempted to transfer SSR markers from taro (Colocasia esculenta), another member of the Araceae and in the same subfamily with caladium.  Thirty-nine SSR-containing taro sequences were identified in the NCBI database, and primers were designed for 22 suitable sequences.  These SSR primers and 43 pairs of previously published taro SSR marker primers were tested on several common caladium cultivars.  Results showed that one pair of the newly designed and four pairs of the published primers could be used in caladium, i.e. 7.7% of taro SSR markers are transferrable to caladium.  This transferability across genus seems to be much lower than that in grass family but higher than that in the Cucurbitaceae.