Characterization Of Tomato Research Articles

Genome-wide identification and characterization of tomato 14-3-3 (SlTFT) genes and functional analysis of SlTFT6 under heat stress.

The plant 14-3-3 proteins are essential for many biological processes and responses to abiotic stress. We performed genome-wide identification and analysis of the 14-3-3 family genes in tomato. To explore the properties of the thirteen Sl14-3-3 found in the tomato genome, their chromosomal location, phylogenetic, and syntenic relationships were analyzed. The Sl14-3-3 promoters were found to have a number of growth-, hormone-, and stress-responsive cis-regulatory elements. Moreover, the qRT-PCR assay revealed that Sl14-3-3 genes are responsive to heat and osmotic stress. Subcellular localization experiments evidenced that the SlTFT3/6/10 proteins occur in the nucleus and cytoplasm Additional analysis on Sl14-3-3 putative interactor proteins revealed a number of prospective clients that potentially participate in stress reactions and developmental processes. Furthermore, overexpression of an Sl14-3-3 family gene, SlTFT6, improved tomato plants thermotolerance. Taken together, the study provides basic information on tomato 14-3-3 family genes in plant growth and abiotic stress response (high temperature stress), which can be helpful to further study the underlying molecular mechanisms. This article is protected by copyright. All rights reserved.

Assay for Phytaspase-mediated Peptide Precursor Cleavage Using Synthetic Oligopeptide Substrates.

Proteases control plant growth and development by limited proteolysis of regulatory proteins at highly specific sites. This includes the processing of peptide hormone precursors to release the bioactive peptides as signaling molecules. The proteases involved in this process have long remained elusive. Confirmation of a candidate protease as a peptide precursor-processing enzyme requires the demonstration of protease-mediated precursor cleavage in vitro. In vitro cleavage assays rely on the availability of suitable substrates and the candidate protease with high purity. Here, we provide a protocol for the expression, purification, and characterization of tomato (Solanum lycopersicum) phytaspases as candidate proteases for the processing of the phytosulfokine precursor. We also show how synthetic oligopeptide substrates can be used to demonstrate site-specific precursor cleavage. Graphical abstract.

Occurrence and characterization of tomato spotted wilt orthotospovirus isolated from cucumber

Occurrence and characterization of tomato spotted wilt orthotospovirus isolated from cucumber

Biological and molecular characterization of tomato spotted wilt virus (TSWV) infecting Chrysanthemum in India

Tomato spotted wilt virus (TSWV) infecting chrysanthemum (Dendranthema grandiflora L.) has been identified as a major constraint for chrysanthemum cut-flower industries in Southern India. The disease symptoms include veinal necrosis, necrotic spots on leaves, deformed flowers, and stem necrosis. The presence of TSWV in chrysanthemum plants collected from farms at Kotagiri, Nedugula, and Yercaud in Tamil Nadu State, India, was confirmed by the triple antibody sandwich-enzyme-linked immunosorbent assay (TAS-ELISA). The pathogenicity of TSWV was established for three isolates (TN1KO, TN2NE, and TN3YE) by mechanical inoculation of sap into chrysanthemum cuttings. Host range experiments in different host plants indicated that the isolates expressed symptoms typical of TSWV in all hosts assayed. Furthermore, Nicotiana tabacum L. had maximum virus titre among the tested host plants, and therefore was identified as the best indicator and the propagative host. The nucleocapsid (N) gene of the three studied isolates shared 99.2–100% identity at the amino acid level among themselves and 96.5–99.6% identity with reference TSWV isolates. The non-structural movement protein (NSm) gene of studied isolates shared 99.0% identity among themselves and 96.0%–100% identity at the amino acid level with reference TSWV isolates. The phylogenetic relationship analyzed based on the amino acid sequence identity of the N gene revealed that the studied isolate clustered as a single group with all the TSWV isolates taken for comparison. However, analysis based on the NSm gene indicated that the Indian isolates grouped with isolates from South Korea, the USA, Italy, Spain, and Australia.

Morphological and agronomic characterization of tomato under field conditions

Morphological and agronomic characterization of tomato under field conditions

Detection and characterization of Tomato spotted wilt virus infecting field and greenhouse-grown crops in Zimbabwe

Tomato spotted wilt virus (TSWV), the type species of the genus Tospovirus in the family Bunyaviridae, is one of the most economically important emerging plant viruses worldwide. It causes over US$1 billion losses annually in open field and greenhouse-grown crops. A study was carried out to determine the geographical distribution, host range and phylogeny of TSWV in Zimbabwe. Disease surveys were conducted in 18 districts over a three-year period using tospovirus immunostrips. Virus-infected leaf samples were collected on FTA cards and in RNAlater solution. TSWV was characterized by double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcription polymerase chain reaction (RT-PCR) followed by sequencing and phylogenetic analysis. The virus was detected in 50% of the districts surveyed, mostly in the country’s prime agricultural region. It was confirmed to be present by DAS-ELISA and RT-PCR. In addition to some previously reported hosts, TSWV was detected for the first time in Cucurbita moschata, Cucurbita pepo, Cucumis sativus and Gyposphila elegans. Molecular analysis of the TSWV nucleocapsid gene showed that Zimbabwean TSWV isolates were highly similar (≥93.99%) and identical (99.02%) to each other at nucleotide and amino acid sequence levels. When compared to isolates from the rest of the world, Zimbabwean TSWV isolates were most closely related to isolates from Italy, Montenegro, New Zealand and Serbia. The study lays the foundation for future TSWV studies by providing protocols and procedures that could be used. Information generated in this study will be useful in formulating effective TSWV control measures.

Cloning and Characterization of Argonaute Genes in Tomato.

Argonaute (AGO) proteins are core elements in plant posttranscriptional RNA silencing pathways. The identification and functional characterization of tomato (Solanum lycopersicum) AGOs will help to better understand RNA silencing-based posttranscriptional regulation in fleshy fruits. Here we describe how to identify and clone SlAGO genes, as well as the methodology for their functional characterization.

Characterization of tomato (Solanum lycopersicum L.) mutants affected in their flowering time and in the morphogenesis of their reproductive structure

The impact of the season on flowering time and the organization and morphogenesis of the reproductive structures are described in three tomato mutants: compound inflorescence (s), single flower truss (sft), and jointless (j), respectively, compared with their wild-type cultivars Ailsa Craig (AC), Platense (Pl), and Heinz (Hz). In all environmental conditions, the sft mutant flowered significantly later than its corresponding Pl cultivar while flowering time in j was only marginally, but consistently, delayed compared with Hz. The SFT gene and, to a lesser extent, the J gene thus appear to be constitutive flowering promoters. Flowering in s was delayed in winter but not in summer compared with the AC cultivar, suggesting the existence of an environmentally regulated pathway for the control of floral transition. The reproductive structure of tomato is a raceme-like inflorescence and genes regulating its morphogenesis may thus be divided into inflorescence and floral meristem identity genes as in Arabidopsis. The s mutant developed highly branched inflorescences bearing up to 200 flowers due to the conversion of floral meristems into inflorescence meristems. The S gene appears to be a floral meristem identity gene. Both sft and j mutants formed reproductive structures containing flowers and leaves and reverting to a vegetative sympodial growth. The SFT gene appears to regulate the identity of the inflorescence meristem of tomato and is also involved, along with the J gene, in the maintenance of this identity, preventing reversion to a vegetative identity. These results are discussed in relation to knowledge accumulated in Arabidopsis and to domestication processes.

Characterization of tomato endo-beta-1,4-glucanase Cel1 protein in fruit during ripening and after fungal infection.

The tomato (Lycopersicon esculentum Mill.) endo-beta-1,4-glucanase (EGase) Cel1 protein was characterized in fruit using specific antibodies. Two polypeptides ranging between 51 and 52 kDa were detected in the pericarp, and polypeptides ranging between 49 and 51 kDa were detected in locules. The polypeptides recognized by Cel1 antiserum in fruit are within the size range predicted for Cel1 protein and could be derived from heterogeneous glycosylation. Cel1 protein accumulation was examined throughout fruit ripening. Cel1 protein appears in the pericarp at the stage in which many ripening-related changes start, and remains present throughout fruit ripening. In locules, Cel1 protein is already present at the onset of fruit ripening and remains constant during fruit ripening. This pattern of expression supports a possible role for this EGase in the softening of pericarp tissue and in the liquefaction of locules that takes place during ripening. The accumulation of Cel1 protein was also analyzed after fungal infection. Cel1 protein and mRNA levels are down-regulated in pericarp after Botrytis cinerea infection but are not affected in locular tissue. The same behavior was observed when fruits were infected with Penicillium expansum, another fungal pathogen. Cel1 protein and mRNA levels do not respond to wounding. These results support the idea that the tomato Cel1 EGase responds to pathogen infection and supports a relationship between EGases, plant defense responses and fruit ripening.

Molecular characterization ofTomato yellow leaf curl China virus and its satellite DNA isolated from tobacco

Virus isolates, Y8, Y36 and Y38, were obtained from tobacco plants showing leaf curl symptoms in Honghe, Yunnan Province. In reactions with 14 monoclonal antibodies raised againstBegomovirus particles, Y8, Y36 and Y38 had similar antigenic reaction in TAS-ELISA asTomato yellow leaf curl China virus (TYLCCNV). The complete DNA-A nucleotide sequences of Y8, Y36 and Y38 were determined and they contain 2727, 2730 and 2730 nucleotides, respectively. Each of the DNA-A sequences has a typicalBegomovirus genome organization encoding 6 ORFs with 2 ORFs [AVl(CP) and AV2] in virion-sense DNA and 4 ORFs (AC1 to AC4) in complementary-sense DNA. Comparisons with total DNA-A, intergenic region and deduced amino acid sequences of individual ORFs show that Y8, Y36 and Y38 are isolates of TYLCCNV. Satellite DNA molecules (DNAβ) were found to be associated with Y8, Y36 and Y38, which consist of 1338, 1339 and 1338 nucleotides, respectively. Comparisons show that these DNAβ molecules share 98%–99% sequence identities on nucleotide level and have a common ORF (designated Cl) encoding 126 amino acids on the complementary strand.

Rheological characterization of tomato concentrates and the effect on uniformity of processing

Rheological characterization of tomato concentrates was performed using MR flow imaging with a 0.6T 1H spectrometer. The experimental design included four concentrations (6,9,12, and 16 degress Brix) and four temperatures (20, 50, 90, and 110 degrees C). The flow profiles were best characterized by a Herschel-Bulkley expression. Apparent viscosity showed Arrhenius-type behavior with temperature. Yield stress values were determined directly from the plug region of the flow profiles and independent pressure drop measurements. Yield stresses ranged from 1.3 to 51 Pa and were a function of both temperature and concentration. In addition, slip velocities, which ranged from 2.3 to 7.8 cm/s, were obtained directly from velocity profiles. The slip velocities were analyzed by ANOVA; the mean values were significantly different with respect to both temperature and concentration. Based on this study, the RTD of tomato concentrates is narrower with increasing temperature and concentration during thermal processing due to the slip velocity and yield stress behavior.

Immunodetection and characterization of tomato endo-beta-1,4-glucanase Cel1 protein in flower abscission zones.

Tomato (Lycopersicon esculentum Mill.) endo-beta-1,4-glucanase Cel1 mRNA accumulation was previously correlated with abscission of flower explants. Cel1 antibodies were raised against a fusion protein encoding a portion of the Cel1 polypeptide and was shown to react specifically with three polypeptides with molecular masses ranging between 51 and 53 kD in flower abscission zones induced to abscise. All three polypeptides were clearly suppressed in two transgenic lines expressing an antisense Cel1 gene that specifically suppressed the accumulation of Cel1 mRNA, indicating that all three polypeptides are products of the Cel1 gene. Cel1 protein accumulation was correlated with flower abscission. Breakstrength and Cel1 protein content were also analyzed in flower explants, indicating that Cel1 protein accumulation is correlated with the final stages of flower shedding, which suggests that Cel1 is involved in the late stage of abscission. These results support the involvement of Cel1 in the abscission of flower explants and suggest that other hydrolase activities also participate in that process.