Epidemics of tomato yellow leaf curl disease (TYLCD) caused by monopartite begomoviruses (family Geminiviridae) result in devastating damage to tomato (Solanum lycopersicum L.) crops in Spain since early 1990’s. | Peer reviewed

Influence of growing environments on chemical and mineral constituents of tomato leaves and taste constituents of tomato fruits were studied. The results are as follows; l. Positive correlations were admitted between the content of potassium and the brix or the acidity of tomato fruits, 2. The GPT and the AMYL activity in leaves of tomato that produced fruits of the high sugar degree by the stress caused by water saving and high EC, were relatively high. 3. Even if brix of fruits was the same, about the acid degree was a little high and the glutamic acid was a half in the tomato harvested in winter compared with the one harvested in summer.

A viroid disease causing chlorosis of leaves and dwarfism was found on commercial tomato plants in Hiroshima Prefecture, Japan. Grafting of stems from infected plants onto healthy plants resulted in the same symptoms on the healthy plants. Small RNAs were isolated from infected plant tissue and caused identical symptoms by 3-4 week after mechanical inoculation of tomato seedlings. Nucleotide sequencing indicated that the causal pathogen was Tomato chlorotic dwarf viroid (TCDVd) sharing 98% nucleotide sequence identity with that of a Canadian isolate reported previously. This description is the first of TCDVd infection of tomato plants in Japan.

To isolate and identify antioomycete substances from Fusarium oxysporum EF119 against Phytophthora infestans and to investigate their antimicrobial activities against various plant pathogenic bacteria, oomycetes and true fungi. Two antioomycete substances were isolated from liquid cultures of F. oxysporum EF119, which shows a potent disease control efficacy against tomato late blight caused by P. infestans. They were identified as bikaverin and fusaric acid by mass and nuclear magnetic resonance spectral analyses. They inhibited the mycelial growth of plant pathogenic oomycetes and fungi. Fusaric acid also effectively suppressed the cell growth of various plant pathogenic bacteria, but bikaverin was virtually inactive. Treatment with bikaverin at 300 μg ml⁻¹ suppressed the development of tomato late blight by 71%. Fusaric acid provided effective control against tomato late blight and wheat leaf rust over 67% at concentrations more than 100 μg ml⁻¹. Both bikaverin and fusaric acid showed in vitro and in vivo antioomycete activity against P. infestans. Fusarium oxysporum EF119 producing both bikaverin and fusaric acid may be used as a biocontrol agent against tomato late blight caused by P. infestans.

The disease caused by Tomato spotted wilt virus (TSWV) belongs to the most destructive diseases of tomato all over the world. Therefore, tomato has been subjected to many breeding efforts, including the incorporation of resistance to the virus. Recently emerged approaches, ideas and technologies could affect the future direction of the virus resistance breeding. In particular molecular techniques have provided opportunities in the form of linked molecular markers to speed up and simplify the selection of host resistance genes. Transformation of an inbred tomato line with the TSWV nucleoprotein gene cassette resulted in high levels of resistance to TSWV that have been retained in the hybrids derived from the parental tomato line. These and other techniques offer great opportunities for improving the virus resistance and, therefore, it is time to reconsider the future direction of resistance breeding in tomato. The effort has been made to review available sources of resistance, conventional breeding methods, marker-assisted selection, pathogen-derived resistance and transgenic resistance approaches in this paper.

Tomato (Lycopersicon esculentum Mill) is one of the most important vegetable crops grown in Turkey and in the world. Tomato stolbur disease is one of the economically important diseases caused by phytoplasmas. Tomato stolbur disease is serious disease of tomato causing yield lose in some areas where prossesing tomato in particularly grown. The objectives of the present study are; 1) to determine the characteristic symptoms and distribution of tomato stolbur disease in Turkey. 2) to investigate spreeding ways of disease in the field conditions. 3) to identify genetic profiles of causal agent , which can be utilized for early diagnosis of disease. | Domates Dünya'da ve Türkiye'de geniş ekim alanlarında üretimi yapılan önemli bir sebzedir. Domates stolbur hastalığı da fitoplazmaların neden olduğu önemli hastalıklardan biridir. Bu hastalık nedeniyle bazı bölgelerde özellikle sanayi domatesi üretiminde zaman zaman önemli ürün kayıpları meydana gelmektedir. Bu çalışmada, domates stolbur hastalığı'nın ülkemizdeki yaygınlığını belirlemek, önemli belirtilerini ortaya koymak, tarlada yayılma yollarını belirlemek ve hastalığın erken teşhisi için patojenin genetik profillerinin belirlenmesi hedeflenmiştir.

The effects of the fungicide Aliette WG 800 (80% fosetyl-Al (aluminium tris-o-ethyl phosphonate)) on the morphology and viability of tomato pollens were studied in tomato plants grown in a greenhouse. The fungicide was applied at recommended dosage (200 g/100 L water) and at double the recommended dosage (400 g/100 L water). The fungicide caused changes in the morphological structures of tomato pollens when applied at 200 g/100 L already. Pollen viability decreased as the dosage increased and non-viable pollen types such as wrinkled cells or pollen with abnormal shape were encountered.

A blue mold on tomato fruit caused by Penicillium oxalicum occurred sporadically in a greenhouse at Gyeongsangnam-do Agricultural Research and Extension Services. Infection usually occurred through wounds or cracks on the fruits. Symptoms began with water soaking lesions, then became watery and softened eventually. Colony of the causal fungus was white at the early growing stage, turned green on Czapek yeast extract agar and malt extract agar. Conidia were ellipsoidal in shape and 2-6×2-4 ㎛ in size. Stipes were septate, smooth, thin walled, and 90-280×3-4 ㎛ in size. Penicilli were mostly biverticillate. Ramuli were 1-3 groups, smooth, and 10-16×2-3 ㎛ in size. Rami were 1-2 groups and 6-30×2-4 ㎛ in size. Metulae were 2-3(5) verticils, smooth, and 12-20×3-4 ㎛ in size. Phialides were 5-7 verticilate, ampulliform to cylindroidal, smooth, and 8-12×2-3 ㎛ in size. Optimum temperature for growth was about 25℃. Pathogenicity of the fungus was proved on tomato fruit according to Koch's postulation. On the basis of mycological and pathological characteristics, the fungus was identified as P. oxalicum Currie and Thom. This is the first report of the blue mold on tomato fruit caused by P. oxalicum in Korea.