Tomato is an important vegetable crop and its production is adversely affected by leaf curl disease caused by begomovirus. Leaf curl disease is a serious concern for tomato crops caused by begomovirus in Jeddah, Kingdom of Saudi Arabia. Tomato leaf curl disease has been shown to be mainly caused either by tomato leaf curl Sudan virus or tomato yellow leaf curl virus as well as tomato leaf curl Oman virus. Many tomato plants infected with monopartite begomoviruses were also found to harbor a symptom enhancing betasatellites. Here we report the association of tomato leaf curl Sudan virus causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia. The complete genome sequence analysis showed highest (99.9 %) identity with tomato leaf curl Sudan virus causing leaf curl disease in Arabian Peninsula. In phylogenetic relationships analysis, the identified virus formed closest cluster with tomato leaf curl Sudan virus. In recombination analysis study, the major parent was identified as tomato leaf curl Sudan virus. Findings of this study strongly supports the associated virus is a variant of tomato leaf curl Sudan virus causing disease in Sudan, Yemen and Arabian Peninsula. The betasatellites sequence analysis showed highest identity (99.8 %) with tomato leaf curl betasatellites-Amaranthus-Jeddah. The phylogenetic analysis result based on betasatellites formed closed cluster with tomato yellow leaf curl Oman betasatellites. The importance of these findings and occurrence of begomovirus in new geographic regions causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia are discussed.

In May 2014, sour rot, an important postharvest disease of tomato, was found on tomato fruit (Solanum lycopersicum var. Roma) in Chiang Mai Province, Thailand. The causal yeast was isolated from lesions and identified as Galactomyces reessii based on morphological, biochemical and physiological characteristics and confirmed using comparisons of DNA sequences of D1/D2 domains of the large subunit ribosomal DNA. The isolated yeast caused rot symptoms on inoculated tomato fruits similar to natural symptoms in the field. This is the first report of tomato sour rot caused by G. reessii.

Tomato (Lycopersicon esculentum Mill.) is widely grown in Nigeria with an average yield of 35 t h-1 and annual yield of approximately 1.8 million t. Tomato production is an important source of income to small holder farmers, but this crop suffers many postharvest diseases caused by fungal pathogens including Alternaria alternata f.sp. lycopersici. Many studies have focused on the effect of heat treatment on mature green tomato to assist subsequent ripening at 20°C with little information of the effect on red tomato. This study focused on the effect of hot water dipping on the control of black mould disease caused by Alternaria alternata and the quality of red tomato. Hot water treatment was carried out on the breaker to turning red tomato (10-30% red USDA Grade Standards, Tomato ripeness stage 1976) purchased from a farm shop in Writtle, Chelmsford Essex, England. They were of equal size and colour. The fruit were inoculated and treated in hot water for 10 min at 40, 45 and 50°C; also at 50 and 55°C for 5 min. The results showed that hot water treatment at 50°C for 10 min and at 55°C for 5 min inhibited disease emergence by 20% in 48 h. Hot water treatment inhibited the pathogen germination and decay development caused by Alternaria alternata. The results showed the fungal pathogen can be inhibited at high temperature in few minutes. Dipping tomato fruit in hot water at 50°C for 10 min or 55°C for 5 min would inhibit germination of spores and reduce decay development caused by Alternaria alternata. The effect of hot water treatment at 40 or 50°C for 10, 20 and 30 min was evaluated on tomato fruit quality such as colour, firmness, aroma, taste and water loss after 24 h storage at 29-30°C and humidity 80-90%. Heat treatment had a significant effect on red colour development and water loss in all the time periods tested but had no effect on firmness and taste.

Postharvest decay and quality deterioration of fruits are responsible for significant economic losses in the tomato industry. Selenium (Se) is an important microelement due to its antioxidant properties that allows detoxifying various reactive oxygen species (ROS). In the present study, the effect of a foliar treatment of Se prior to fruit development on the subsequent postharvest decay and quality of tomato fruits was investigated. Foliar treatment of 1mgL−1 sodium selenate at the time of fruit onset and development effectively controlled gray mold rot caused by Botrytis cinerea on both inoculated and naturally infected tomato fruit. Se treatment reduced lipid peroxidation, enhanced antioxidant enzyme activity of glutathione peroxidase and superoxide dismutase, and increased the concentration of non-enzymatic antioxidants, such as reduced ascorbate and reduced glutathione in the tomato fruits. Se also contributed to the maintenance of fruit quality during storage. The results suggested that Se stimulated the antioxidant defense system in tomato plants, thus making the fruits more resistant to postharvest decay caused by gray mold. Selenium treatment represents a promising strategy for managing postharvest decay and maintaining the quality of tomato fruits.

Postharvest decay caused by fungal pathogens is responsible for significant economic losses in the tomato industry. Induction of disease resistance in harvested horticultural crops is an approach to controlling postharvest losses that is being actively investigated. In the current study, the effects of harpin (a bacterial hypersensitive response elicitor) on gray mold and black rot caused by Botrytis cinerea and Alternaria alternata, respectively, in tomato fruit were investigated. Harpin effectively controlled gray mold and black rot on inoculated tomato fruit, as well as natural infection. Harpin treatment at 90mgL−1 induced the transcript expression of defense-related genes including chitinase, β-1,3-glucanase and phenylalanine ammonia-lyase based on RT-qPCR analysis, increased the activity of these enzymes, and the content of total phenolic compounds and lignin in tomato fruit. Moreover, harpin did not demonstrate any fungicide effect on B. cinerea or A. alternata in vitro. These findings suggest that the effect of harpin on postharvest diseases was attributed to the elicitation of resistant responses, and harpin treatment may represent a promising strategy for managing postharvest decay of tomato fruit.

This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth.

An integrated management of bacterial wilt of tomato against race 1 biovar III of Ralstonia solanacearum was conducted with eleven treatment combinations on resistant (cv Swarna Lalima) and susceptible (cv. Pusa Ruby) of tomato from 2006 to 2009-10 during rainy seasons. The pooled analysis of different treatments × variety × date of sampling were showed significanteffects on Ralstonia population, wilt incidence and yield of the crop. This treatment also reduced R. solanacearum population and increased the yield 47.2% in cv. Swarna Lalima (343.7 q/ha) with B: C ratio (1.49:1) over resistant check.