Developmental regulation of Mi-mediated aphid resistance is independent of Mi-1.2 transcript levels

• Published in: Molecular plant-microbe interactions Vol. 17; no. 5; pp. 532 - 536
• Main Authors: Goggin, F.L, Shah, G, Williamson, V.M, Ullman, D.E
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01-05-2004; American Phytopathological Society; The American Phytopathological Society
• Subjects: Animals; Aphididae; Aphidoidea; Aphids - growth & development; Biological and medical sciences; Flowers - genetics; Flowers - growth & development; Flowers - parasitology; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; gene overexpression; Immunity, Innate - genetics; insect resistance; Lycopersicon esculentum; Lycopersicon esculentum - genetics; Lycopersicon esculentum - growth & development; Lycopersicon esculentum - parasitology; Macrosiphum euphorbiae; messenger RNA; molecular sequence data; nucleotide sequences; pest resistance; Phytopathology. Animal pests. Plant and forest protection; Plant Diseases - genetics; Plant Diseases - parasitology; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - parasitology; plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Reproduction - genetics; Reproduction - physiology; Solanum lycopersicum var. lycopersicum; tomatoes; Resistance; Aphidoidea; Messenger RNA; Homoptera; Microbiology; Arthropoda; Insecta; Aphididae; Invertebrata
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi.2004.17.5.532

Mi-1.2, a member of the intracellular, nucleotide-binding site-leucine-rich repeat family of resistance genes, confers resistance in tomato (Lycopersicon esculentum) against both root-feeding nematodes and leaf-feeding aphids. Nematode resistance is effective in all life stages of the plant; in contrast, Mi-mediated aphid resistance is developmentally regulated, and protects mature plants but not seedlings against aphid infestation. To determine if the onset of aphid resistance is regulated by Mi-1.2 transcript abundance, we compared aphid resistance and Mi-1.2 transcript levels in seedlings and flowering plants. Paired bioassays and RNase protection assays revealed that Mi-1.2 is transcribed in the leaves prior to the onset of aphid resistance, and that transcript levels are comparable in seedlings and flowering life stages. Furthermore, constitutive overexpression of Mi-1.2 in transgenic plants did not hasten the onset of aphid resistance in seedlings, or boost the level of resistance observed in flowering plants. These data demonstrate that Mi-1.2 transcript levels do not modulate the degree of aphid resistance in tomato leaves, or control the differences in regulation between aphid and nematode resistance.