Chapter 4 - Going Green: RNA and the Molecular Biology of Plants

Abstract

Plants exhibit complex gene expression pathways and regulatory controls that are often similar to those observed in animals. Therefore, the techniques that are commonly used to assay gene expression in animal cells may be used to assay the same in plants. The features of plant cells that distinguish them from animal cells are: the presence of a cell wall; the presence of a large fluid-filled vacuole; and the presence of chloroplasts. High-quality RNA is isolated from vastly different plant tissues, such as leaf, root, bark, floral tissue, fruit, and cotyledon. RNA is chemically the same type of molecule regardless of its biological source but the fibrous nature of plant tissue often requires far more aggressive measures to disrupt cells than are required for an equal starting mass of animal tissue. The important consideration for isolating plant RNA is the method for dismantling or breaking through the formidable cell wall; and these methods include: pulverizing plant tissue that has been frozen in liquid nitrogen, the use of an electronic homogenizer or a Bead Beater, or a laboratory blender or similar apparatus. One of the primary complaints associated with RNA isolation from plant tissue is an unacceptably low yield, because of the plant cell wall; high concentrations of phenolics; and high concentrations of polysaccharides, waxes, and latex. The amount of RNA that is to be expected is highly dependent upon the plant species, the specific tissue, and the isolation procedure.