Constitutive expression of a trypsin protease inhibitor confers multiple stress tolerance in transgenic tobacco

• Published in: Plant and cell physiology Vol. 50; no. 3; pp. 541 - 553
• Main Authors: Srinivasan, T.(University of Hyderabad (India)), Kumar, K.R.R, Kirti, P.B
• Format: Journal Article
• Language: English
• Published: Japan Oxford University Press 01.03.2009; Oxford Publishing Limited (England)
• Subjects: Amino Acid Sequence; Base Sequence; Cloning, Molecular; ESTRES OSMOTICO; Gene Expression Regulation, Plant; Genes, Plant; Helicoverpa armigera; Hydrogen-Ion Concentration; INHIBIDORES DE PROTEINASAS; INHIBITEUR DE PROTEINASES; Insect resistance; INSECTE NUISIBLE; INSECTOS DANINOS; Molecular Sequence Data; Nicotiana - genetics; Nicotiana - metabolism; NICOTIANA TABACUM; Open Reading Frames; Oryza sativa; OSMOTIC STRESS; Osmotic stress tolerance; PEST INSECTS; Plant Proteins - genetics; Plant Proteins - metabolism; PLANTAS TRANSGENICAS; PLANTE TRANSGENIQUE; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Potassium - analysis; Protease inhibitor; PROTEINASE INHIBITORS; RNA, Plant - genetics; Salt-Tolerant Plants - genetics; Salt-Tolerant Plants - metabolism; Sequence Analysis, DNA; Sodium - analysis; Spodoptera litura; STRESS OSMOTIQUE; Stress, Physiological; TOLERANCE; TOLERANCIA; TRANSGENIC PLANTS; Transgenic tobacco; Trypsin Inhibitors - genetics; Trypsin Inhibitors - metabolism; Wide pH range; Transgenic tobacco; Insect resistance; Wide pH range; Protease inhibitor; Osmotic stress tolerance
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcp014

Protease inhibitors have been reported to confer insect resistance in transgenic plants, except for a rice protease inhibitor that conferred drought tolerance in transgenic rice plants. We have cloned a protease inhibitor of tobacco that is expressed under treatment with ABA, hydrogen peroxide, methyl jasmonate and wounding. The cDNA codes for a six-domain serine protease inhibitor with a deduced sequence of 396 amino acids. We have generated transgenic tobacco plants expressing the protease inhibitor constitutively under the 35S promoter. When analyzed in the Tsub(2) generation, these transgenic plants exhibited tolerance to sodium chloride, variable pH and sorbitol, together with the expected resistance to the insect pests Spodoptera litura and Helicoverpa armigera. The transgenic plants showed enhanced seed germination, root length and root-shoot ratio, significantly enhanced total chlorophyll content and reduced thiobarbituric acid-reactive substances under stress. Under sodium chloride treatment, the transgenic plants have enhanced protease inhibitor activity. The transgenic plants exhibited a higher potassium content and an optimum Nasup(+)/Ksup(+) ratio. To our knowledge, this is the first report of transgenic plants with constitutive protease inhibitor expression showing tolerance to a wide range variable pH in the culture medium along with other stresses.