A Leaf Lipoxygenase of Potato Induced Specifically by Pathogen Infection

• Published in: Plant physiology (Bethesda) 2000-11, Vol.124 (3), p.1121-1130
• Main Authors: Kolomiets, Michael V., Chen, Hao, Gladon, Richard J., E. J. Braun, Hannapel, David J.
• Format: Article
• Language: English
• Subjects: Accumulation; Agronomy. Soil science and plant productions; Amino acids; Biological and medical sciences; Blotting, Northern; Blotting, Southern; Complementary DNA; Enzyme Induction; Fundamental and applied biological sciences. Psychology; Generalities. Disease free stocks; Genetics and breeding of economic plants; Infections; Inoculation; Leaves; Lipoxygenase - biosynthesis; Lipoxygenase - genetics; Messenger RNA; Pathogens; Pest resistance; Phytopathology. Animal pests. Plant and forest protection; Phytophthora; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Leaves - microbiology; Plant pathogens; Plants; Plants Interacting with Other Organisms; Potatoes; Pseudomonas; RNA; RNA, Messenger - analysis; RNA, Plant - analysis; Solanum tuberosum - enzymology; Solanum tuberosum - genetics; Solanum tuberosum - microbiology; Tubers; Varietal selection. Specialized plant breeding, plant breeding aims; Vegetables
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.124.3.1121

Lipoxygenase (LOX) activity has been identified consistently during pathogen-induced defense responses. Here we report the involvement of a specific leaf LOX gene of potato (Solanum tuberosum), designated POTLX-3 (GenBank/EMBL accession no. U60202), in defense responses against pathogens. The sequence of POTLX-3 does not match any other LOX genes of potato and has the greatest match to a tobacco LOX gene that contributes to a resistance mechanism against Phytophthora parasitica var nicotianae. POTLX-3 transcript accumulation was not detected in untreated, healthy potato organs or in wounded mature leaves. POTLX-3 mRNA accumulation was induced in potato leaves treated with ethylene or methyl jasmonate or infected with either virulent or avirulent strains of Phytophthora infestans, the causal agent of late blight. During the resistance response, POTLX-3 was induced within 6 hours, increased steadily through 24 hours, and its mRNA continued to accumulate for a week after inoculation. In contrast, when a plant was susceptible to P. infestans, induction of mRNA accumulation in response to inoculation was inconsistent and delayed. LOX activity assayed during an incompatible interaction in leaves peaked 3 days earlier than during a compatible interaction. POTLX-3 mRNA accumulation also was induced during hypersensitive response development caused by the incompatible pathogen Pseudomonas syringae pv phaseolicola. Our results show that POTLX-3 may be involved specifically in defense responses against pathogen infection.