0000000000285224
AUTHOR
Fernando Nuez
Viral diseases causing the greatest economic losses to the tomato crop. II. The Tomato yellow leaf curl virus — a review
Abstract Tomato yellow leaf curl geminivirus (TYLCV), transmitted by the whitefly Bemisia tabaci (Gennadius) is one of the most devastating diseases of cultivated tomato (Lycopersicon esculentum Mill.). TYLCV causes economic losses up to 100% in tomato crop in many tropical and subtropical regions, and is spreading towards new areas. The increasing economic importance of TYLCV has resulted in the need for accurate detection and identification procedures, stimulating intensive research efforts focused on virus biology, diversity, and epidemiology to develop successful control strategies. Breeding for resistance appears to be the best approach to control this disease, but to date only partial…
Relationship between radial and concentric cracking of tomato fruit
Abstract A study with 62 genotypes was carried out to establish correlations existing between the percentages of fruits showing concentric cracks of more or less than 2 cm and radial cracks of more or less than 2 cm, considering both early and total production. Over a determined productive period, the susceptibility to form large or small cracks was controlled by the same genetic system (rG = 0.89 – 0.95), yet there was a genetic difference between susceptibility to radial and concentric cracking (rG = 0.53 – 0.68). Genetic systems for susceptibility to radial and concentric cracking seemed to show similarly over the first harvesting and over the total productive period ( r G ⋍ 1 ). Environ…
Fast determination of prominent carotenoids in tomato fruits by CEC using methacrylate ester-based monolithic columns.
In this study, the major carotenoids (beta-carotene and lycopene) present in tomato fruits were analyzed by CEC with a methacrylate ester-based monolithic column. The effects of the porogenic solvent ratio, and the hydrophobicity of bulk monomer employed were examined on carotenoids separations. A fast separation of these analytes was achieved in less than 5.0 min in a mobile phase containing 35% THF, 30% ACN, 30% methanol, and 5% of a 5 mM Tris aqueous buffer, pH 8, with lauryl methacrylate-based monoliths. The CEC method was evaluated in terms of detection limit and reproducibility (retention time, area, and column preparation) with values below 1.6 microg/mL and 7.2%, respectively. The p…
High efficiency joint CZE determination of sugars and acids in vegetables and fruits
In this work, an improved CE method for the medium-throughput determination of main organic acids (oxalate, malate, citrate), the amino acid glutamate and the sugars fructose, glucose and sucrose in several food matrices is described. These compounds have been identified as key components in the taste intensity of fruit and vegetable crops. Using a running buffer with 20 mM 2,6-pyridine dicarboxylic acid pH 12.1 and 0.1% hexadimethrine bromide, replacing it every 5 h to avoid pH decrease, and optimizing capillary conditioning between runs with 58 mM SDS during 2 min at 20 psi, it is possible to effectively quantify these compounds while increasing medium throughput repeatability. This proce…
Viral diseases causing the greatest economic losses to the tomato crop. I. The Tomato spotted wilt virus — a review
Abstract Tomato spotted wilt virus (TSWV) is one of the most important diseases affecting tomatoes, occasionally leading to losses of up to 100%. Because of the importance of this virus disease, considerable research has been carried out in recent years on the viral particle, disease vectors, transmission and control methods. This review presents an account of the current state of research on TSWV with special reference to tomato. Genetic resistance appears as the best solution to control this disease. It may be complemented with other strategies of control aimed to reduce inoculum amount or to avoid transmission, since these strategies have been shown to be ineffective to stop the disease …
Determination of -Ascorbic Acid in Lycopersicon Fruits by Capillary Zone Electrophoresis
This study shows an improved method for the determination of L-ascorbic acid (l-AA) in fruits of Lycopersicon by capillary zone electrophoresis (CZE). Two backgrounds electrolytes (BGEs) have been tested: (i) 400 mM borate at pH 8.0 and 1 x 10(-2)% hexadimethrine bromide, for the separation of Eulycopersicon subgenus species; and (ii) as in BGE(i) but supplemented with 20% (v/v) acetonitrile, for the separation of species of the Eriopersicon subgenus. The present procedures were compared with two routine methods-enzymatic assay and potentiometric titration with 2,6-dichlorophenol-indophenol. While these routine methods presented some difficulties in quantifying l-AA in several Lycopersicon …
Simultaneous quantification of the main organic acids and carbohydrates involved in tomato flavour using capillary zone electrophoresis
A capillary zone electrophoresis (CZE) procedure for the simultaneous determination of the major organic acids (oxalate, malate and citrate) and carbohydrates (fructose, glucose and sucrose) in Lycopersicon fruits is reported. Comparison of this method with routine HPLC methods indicates that the CZE method offers several attractive features (speed, resolution, sensitivity and cost) which significantly improve the determination of these compounds. Detection limits were better than 1.6 µg ml−1 for organic acids and from 13 to 24 µg ml−1 for carbohydrates; repeatabilities were better than 2.1% for migration times and between 1.4 and 7.3% for peak areas. The proposed protocol is very useful to…