Sedyo Hartono

Yellowing disease of tomato caused by Tomato chlorosis virus newly recognized in Japan

In 2008, virus-like symptoms of yellowing, interveinal chlorosis, leaf curling and necrotic fleck were observed on greenhouse-tomato plants (Solanum esculentum) in Tochigi Prefecture. The symptomatology and the characteristics of the causal agent such as whitefly transmissibility and particle morphology are similar to those for Tomato infectious chlorosis virus (TICV) and Tomato chlorosis virus (ToCV), species of the genus Crinivirus in the family Closteroviridae. Sequencing of reverse transcription-polymerase chain reaction (RT-PCR) products using the degenerate primers for heat shock protein 70 homolog genes of closteroviruses and specific primers for TICV and ToCV indicated that the virus was ToCV, that has not previously been reported in Japan.

Survey and Detection of Pectobacterium atrosepticum in Major Potato-Growing Areas in Central Java Province, Indonesia

Potato ( Solanum tuberosum ) is a seasonal shrub-tuber crop originated from sub-tropical area. Soft-rot is one of the most important diseases of potato. It can be caused by Pectobactorium atrosepticum , a pathogen within a status of quarantine plant pest A1 type I in Indonesia. The objective of this study was to know the incidence of potato soft rot disease and to detect P. atrosepticum in major potato-growing areas in Central Java Province by applying the serology method using DAS-ELISA technique. Survey of soft rot disease was carried out in some regencies in Central Java Province, i.e. Magelang, Banjarnegara, Wonosobo and Karanganyar. The field survey of potato plant in all the regencies indicated symptoms of stem rot which was black in color (blackleg) and foul-smelling, with disease incidence of about 10–90%. The laboratory testing showed that by applying DAS-ELISA method, P. atrosepticum was detected in samples collected from Pandean and Bagongan villages, district of Ngablak,Regency of Magelang, Central Java Province.

Development of a LAMP assay with a portable device for real-time detection of begomoviruses under field conditions

The emergence of begomovirus infection is one of the most important problems affecting production of a variety of vegetable crops worldwide. Infection by begomoviruses has been detected and spread rapidly on Cucurbitaceae and Solanaceae plants in Indonesia. A rapid and simple detection assay for begomoviruses under field conditions for routine sampling of plants is needed. Primers for a loop-mediated isothermal amplification (LAMP) assay were designed based on the sequences of three Indonesian begomoviruses, namely Tomato leaf curl New Delhi virus (ToLCNDV), Pepper yellow leaf curl Indonesia virus (PepYLCIV), and Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV), infecting Cucurbitaceae and Solanaceae plants. LAMP assays using a Genelyzer™ III portable fluorometer with a toothpick method successfully detected these begomoviruses in infected melon, pepper, and eggplant samples. LAMP assays conducted during a field survey for detection of the three begomoviruses on 104 fresh leaves indicated that most of the samples were positive; the findings were confirmed by PCR using universal primers of begomovirus as a common detection method. These results demonstrate that this simple and rapid LAMP assay using a fluorometer portable device may be used to achieve real-time detection of begomoviruses under field conditions.

Molecular Evidence for Mixed Infections of Four Begomoviruses in Common Bean and Yard Long Bean Showing Severe Yellow Symptoms in East Java, Indonesia

The genus Begomovirus (family Geminiviridae) is transmitted by whitefly (Bemesia tabaci) in a persistent manner and causes yellowing disease symptoms with significant losses of leguminous crops in Indonesia. Mixed infection with Begomovirus was detected using a polymerase chain reaction assay using four pairs of specific primers: AC2-F/AC2-R, TYLCV-F/TYLCV-R, TLCV-CPI/TLCV-CPT, and PepYLCV-F/PepYLCV-R, amplifying the targeted DNA fragments of ~504 bp, ~1668 bp, ~700 bp, and ~850 bp, respectively. Samples were collected from different geographic areas in East Java (Kencong and Pujon), which represented the difference in altitudes. Molecular evidence indicated that the Tomato yellow leaf curl virus (TYLCV), Tomato leaf curl virus (ToLCV), Pepper yellow leaf curl virus (PepYLCV), and Mungbean yellow mosaic virus (MYMV) co-infected common bean plants showing mosaic symptoms, cupping, leaf malformations, yellowing, and stunting. ToLCV, PepYLCV, and MYMV were found in mixed infections of yard long bean with mosaic and yellowing symptoms. Common bean and yard long bean only infected by ToLCV or PepYLCV showed mosaic symptoms. Symptoms of yellow disease in infected common bean and yard long bean in the Kencong area showed more complexes than those in Pujon.

Identification, distribution and genetic diversity of the golden potato cyst nematode (Globodera rostochiensis) in Java Indonesia

Golden potato cyst nematode (Globodera rostochiensis (Wollenweber) Behrens) is a nematode species which has worldwide regulatory concern. This nematode causes serious economic problem of potato losses in Indonesia. To study the distribution and genetic diversity of G. rostochiensis, 30 soil samples were collected from Java island, Indonesia. Seventeen out of thirty samples were infected by G. rostochiensis obtained from Pangalengan West Java, Wonosobo Central Java, Banjarnegara Central Java, Probolinggo East Java and Malang East Java. PCR assay with specific primers for G. rostochiensis (PITSr3) produced a single band of 434 base pairs (bp) length from all samples. The internal transcribed spacer (ITS1 and ITS5) regions were subjected to direct sequencing to study the genetic diversity of these populations. Five representative isolates were sequenced and compared with the sequences which available in GenBank. The sequencing data showed that all of the five population represented the same species, G. rosto...

Keragaman Virulensi dan Konstruksi Molekuler Virus Tungro pada Padi dari Daerah Endemis

Tungro is an important disease of rice, constraining to the rice production in Indonesia. Tungro is caused by the infection of two different viruses namely tungro bacilliform virus (RTBV) and tungro spherical virus (RTSV). Both viruses are only transmitted by green leafhoppers, especially Nephotettix virescens in a semipersistent manner. The variation of tungro viruses from different areas had been reported, and there is a specific relationship between resistance variety and tungro virus isolate. It is important therefore, to study the virulences and the genetic diversities of tungro viruses derived from the endemic areas in Indonesia. This study was aimed to identify the virulence and the molecular diversity of tungro viruses from endemic areas in Indonesia. Susceptible variety TN1 was used in the study. Surveys and collection of the infected plants and green leafhoppers were conducted in some tungro endemic areas, including: West Java, Central Java, Yogyakarta, Central Sulawesi, West Sulawesi, South Sulawesi, Bali and West Nusa Tenggara. Artificial virus transmission using test tube method was used in the virulence test. Green leafhoppers caught from the field were used as vector transmitters. The virulence of tungro viruses was determined based on diseases indexes (DI). Results showed that the virulence of tungro viruses varied among region in the endemic areas in Indonesia. The Central Java virus isolate was the most virulence; however, not all isolates from endemic areas in the island of Java were more virulent than those from outside of Java. The presence of RTBV and RTSV was detected in the infected TN1 plants. The existences of molecular diversities of tungro viruses from the endemic areas were observed. The relationship between combination of DNA bands of RTBV and RTSV with the virulence in endemic areas outside of Java was more complex than it was in West Java and Central Java. The molecular diversities of tungro viruses were not correlated with the geographic difference of the endemic areas, nor with the virulences.