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...

We test the convergence property of the chiral perturbation theory using a lattice QCD calculation of pion mass and decay constant with two dynamical quark flavors. The lattice calculation is performed using the overlap fermion formulation, which realizes exact chiral symmetry at finite lattice spacing. By comparing various expansion prescriptions, we find that the chiral expansion is well saturated at the next-to-leading order for pions lighter than approximately 450 MeV. Better convergence behavior is found, in particular, for a resummed expansion parameter xi, with which the lattice data in the pion mass region 290-750 MeV can be fitted well with the next-to-next-to-leading order formulas. We obtain the results in two-flavor QCD for the low energy constants l[over ]_{3} and l[over ]_{4} as well as the pion decay constant, the chiral condensate, and the average up and down quark mass.

Ralstonia solanacearum is the causal agent of bacterial wilt (BW), one of the most important bacterial diseases worldwide. We used cDNA microarray to survey the gene expression profile in transgenic tomato (Solanum lycopersicum) overexpressing Arabidopsis (Arabidopsis thaliana) CBF1 (AtCBF1), which confers tolerance to BW. The disease-resistant phenotype is correlated with constitutive expression of the Related-to-ABI3/VP1 (RAV) transcription factor, ethylene-responsive factor (ERF) family genes, and several pathogenesis-related (PR) genes. Using a transient assay system, we show that tomato RAV2 (SlRAV2) can transactivate the reporter gene driven by the SlERF5 promoter. Virus-induced gene silencing of SlERF5 and SlRAV2 in AtCBF1 transgenic and BW-resistant cultivar Hawaii 7996 plants gave rise to plants with enhanced susceptibility to BW. Constitutive overexpression of SlRAV2 in transgenic tomato plants induced the expression of SlERF5 and PR5 genes and increased BW tolerance, while knockdown of expression of SlRAV2 inhibited SlERF5 and PR5 gene expression under pathogen infection and significantly decreased BW tolerance. In addition, transgenic tomato overexpressing SlERF5 also accumulated higher levels of PR5 transcripts and displayed better tolerance to pathogen than wild-type plants. From these results, we conclude that SlERFs may act as intermediate transcription factors between AtCBF1 and PR genes via SlRAV in tomato, which results in enhanced tolerance to BW.