Tomato Plants Ectopically Expressing Arabidopsis CBF1 Show Enhanced Resistance to Water Deficit Stress

Abstract

A DNA cassette containing an Arabidopsis C repeat/dehydration-responsive element binding factor 1 (CBF1) cDNA and a nos terminator, driven by a cauliflower mosaic virus 35S promoter, was transformed into the tomato (Lycopersicon esculentum) genome. These transgenic tomato plants were more resistant to water deficit stress than the wild-type plants. The transgenic plants exhibited growth retardation by showing dwarf phenotype, and the fruit and seed numbers and fresh weight of the transgenic tomato plants were apparently less than those of the wild-type plants. Exogenous gibberellic acid treatment reversed the growth retardation and enhanced growth of transgenic tomato plants, but did not affect the level of water deficit resistance. The stomata of the transgenic CBF1 tomato plants closed more rapidly than the wild type after water deficit treatment with or without gibberellic acid pretreatment. The transgenic tomato plants contained higher levels of Pro than those of the wild-type plants under normal or water deficit conditions. Subtractive hybridization was used to isolate the responsive genes to heterologous CBF1 in transgenic tomato plants and the CAT1 (CATALASE1) was characterized. Catalase activity increased, and hydrogen peroxide concentration decreased in transgenic tomato plants compared with the wild-type plants with or without water deficit stress. These results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants.Many environmental stresses, such as heat, salinity, low temperature, and drought, and developmental processes, such as seed maturation, cause water deficit in plants (Ingram and Bartels, 1996). To understand water deficit stress at the molecular level, many genes have been isolated, such as rd (responsive to dehydration), erd (early responsive to dehydration), and Lea (late embryogenesis abundant; Shinozaki and Yamaguchi-Shinozaki, 2000). The accumulation of LEA protein occurs during seed maturation, desiccation, and increases in vegetative tissue when plants are exposed to water deficit (Ingram and Bartels, 1996). Overexpression of a barley (Hordeum vulgare) group 3 LEA protein gene, HVA1, enhances tolerance of water deficit and salt stress in transgenic rice (Oryza sativa; Xu et al., 1996). Arabidopsis RD29A (COR78) responds to water deficit and low-temperature stresses (Horvath et al., 1993; Yamaguchi-Shinozaki and Shinozaki, 1993). Study of the promoter RD29A has lead to the characterization of a 9-bp element, TACCGACAT, referred to as dehydration-responsive element (DRE), that is also found in the promoter regions of many water deficit and cold responsive genes, such as RD17, ERD10, KIN1, COR15a, and COR6.6 (Yamaguchi-Shinozaki and Shinozaki, 1994; Wang et al., 1995; Thomashow, 1999). The DRE element contains a 5-bp core sequence of CCGAC, also known as C repeat (CRT), that plays an important role in regulating gene expression in response to low temperature, water deficit, and high salinity (Baker et al., 1994; YamaguchiShin...

The unique mode of action of a divergent member of the ABA-receptor protein family in ABA and stress signaling

“…Although OE-OsMYB3R-2 exhibited enhanced cold tolerance in rice, it also resulted in growth retardation under normal conditions [42]. Similarly, OE-DREB1A in Arabidopsis caused severe growth retardation [41], and overexpression of CBF1 in tomato resulted in a dwarf phenotype [43]. These results indicate that constitutive activation of stress-responsive genes increases stress tolerance but may also result in growth retardation.…”

Tomato RAV Transcription Factor Is a Pivotal Modulator Involved in the AP2/EREBP-Mediated Defense Pathway

“…In previous studies, we have demonstrated that constitutive expression of AtCBF1 in tomato increased tolerance to chilling and water deficit (Hsieh et al, 2002a(Hsieh et al, , 2002b. To identify the genes that were differentially expressed in AtCBF1 transgenic tomato plants, we now used subtractive hybridization and homemade microarray systems (Liu et al, 2006).…”

“…Thus, we conclude that constitutive expression of AtCBF1 in transgenic tomato enhances BW resistance by systemic suppression of internal bacterial multiplication via the activation of PR proteins. Constitutive expression of AtCBF1 in tomato resulted in a dwarf phenotype that was alleviated by the application of GA 3 (Hsieh et al, 2002a(Hsieh et al, , 2002b. To test whether GA 3 is a common antagonist of the AtCBF network that not only restores the dwarf and lateflowering phenotype but also influences the expression of the PR genes, we examined the expression levels of PR genes in AtCBF1 transgenic lines (C5, C15, and C21) and wild-type plants in the presence and absence of GA 3 treatment by northern-blot analyses (Fig.…”

“…Moreover, overexpression of cDNA encoding CBF3 in transgenic Arabidopsis activated several stress-tolerance genes, thus enhancing the tolerance of plants to drought, freezing, and salt stresses (Liu et al, 1998;Gilmour et al, 2000;Sakuma et al, 2006). Previously, we have reported that transgenic tomato expressing Arabidopsis CBF1 (AtCBF1) cDNA is tolerant to various abiotic stresses such as chilling, oxidative stress, high salt, and water deficit (Hsieh et al, 2002a(Hsieh et al, , 2002bLee et al, 2003). Here, we report that AtCBF1 transgenic tomato plants are tolerant to Ralstonia infection in greenhouse experiments and that AtCBF1 modulates the plant defense response against Ralstonia by repressing the proliferation of bacteria in vascular tissues.…”

Benefits and Costs of Biologically Contained Genetically Modified Tomatoes and Eggplants in Italy and Spain

“…One of these properties is reduced water deficit stress [25], which could allow cultivation on currently marginal land that meets tomato-production conditions in other respects. Conversely, it reduces the opportunity costs of growing tomato, as less water may be needed in the cultivation process.…”