Constitutive Expression of a Trypsin Protease Inhibitor Confers Multiple Stress Tolerance in Transgenic Tobacco

Abstract

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 T(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 Na+/K+ 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.

Characterization of proteinase inhibitor-II gene under OsRGLP2promoter for salt stress in transgenic Nicotiana benthamiana

“…However, transgenics at lower concentrations showed earlier growth than at higher concentrations. A similar phenotypic response was noted in transgenic plants overexpressing the rice chymotrypsin proteinase inhibitor (OCPI2) (Tiwari et al, 2015) and a tobacco PI (NtPI) (Srinivasan et al, 2009).…”

“…Protein degradation can be controlled by curbing proteases and PIs are said to inhibit this protease activity. Transgenic plants constitutively expressing the PIs have the advantage of increased proteinase inhibitory activity and enhanced stress tolerance (Huang et al, 2007;Srinivasan et al, 2009). Salt tolerance exhibited by PI transgenics might be due to inhibition of sodium translocation to the other parts of plants from the root system (Shan et al, 2008;Srinivasan et al, 2009).…”

“…Transgenic plants constitutively expressing the PIs have the advantage of increased proteinase inhibitory activity and enhanced stress tolerance (Huang et al, 2007;Srinivasan et al, 2009). Salt tolerance exhibited by PI transgenics might be due to inhibition of sodium translocation to the other parts of plants from the root system (Shan et al, 2008;Srinivasan et al, 2009). In the present study, the overall constitutive expression of the PI-II gene in transgenic plants under salt stress might result in increased PI-II activity, which ultimately leads to increased salt tolerance.…”

“…Under such conditions, plants have evolved sophisticated mechanisms for upregulation of genes that can eliminate or reduce the effects of these stresses. Plant proteinase inhibitors (PIs) are among the promising defensive proteins that help plants resist different kinds of environmental stresses (biotic and abiotic) (Ryan, 1990;Fujita et al, 2006;Srinivasan et al, 2009). In plants, PIs inhibit the proteolytic activity of their target proteases under stress conditions, and thus the stability of vital cellular proteins and enzymes increases, leading to enhanced stress tolerance.…”

Respuesta de los frutos cítricos a las bajas temperaturas: estudio mediante micromatrices

“…Las miraculinas tienen estructura homóloga a inhibidores de tripsina (Theerasilp et al, 1989) y éstos suelen inducirse en respuesta a distintos estreses (Botelho-Junior et al, 2008) y proteger frente a los mismos (Srinivasan et al, 2009). Asimismo, las miraculinas parecen ser parte de una situación preformada (previa a la exposición al estrés) que resultaría en un estado de tolerancia más activada en CN que en F. …”