Search

Aphid-borne viral infection is a major limiting factor for groundnut production in South Sulawesi, Indonesia. The study aimed to elucidate the effectiveness of integrated management packages (IMP) in controlling aphid-borne viruses infecting groundnut in the field. Field trials were conducted in a plot without (M0) and with plastic mulch and maize as a plant barrier (M1), while two different groundnut varieties, Bougainvillea leaf extract, and insecticides were incorporated as the subplot treatments. The treatments in M1 plot significantly reduced the aphid population (17.4–79.9%) and AUDPC incidence (51.7–87.3%), and severity (61.0–92.9%), respectively. The treatments increased dry pod production by 11.9–63.3% depending on subplot treatment compared to treatments in the M0 plot (p>0.05). Bean common mosaic virus strain PSt and Cowpea Polerovirus 2 were positively detected in groundnuts as well as in aphids using RT-PCR. Further, nine weed species in the vicinity of the field trial were found to be positively infected with BCMV-PSt, indicating their crucial role as reservoir hosts. Interestingly, the effectiveness of Bougainvillea leaf extract treatment in the M1 plot was comparable to that of the insecticide treatment, indicating that this IMP is a more cost-effective, eco-friendly groundnut virus control than the currently used method.

Kecombrang (Etlingera elatior) merupakan tanaman rempah tradisional yang banyak dimanfaatkan sebagai antimikrob dalam dunia medis di Indonesia. Namun, potensi kecombrang sebagai fungisida nabati dalam fitopatologi perlu dikaji lebih lanjut. Penelitian bertujuan menguji aktivitas anticendawan ekstrak rimpang dan daun kecombrang dalam pelarut metanol dan etanol terhadap Colletotrichum acutatum. Pengujian secara in vitro ekstrak kecombrang dilakukan dengan teknik peracunan medium dengan lima taraf konsentrasi. Parameter yang diamati diameter koloni, sporulasi, dan perkecambahan konidium. Pengujian secara in vivo dilakukan pada buah cabai rawit dengan parameter yang diamati masa inkubasi, insidensi dan keparahan penyakit, serta keefektifan perlakuan. Di antara konsentrasi yang diuji, ekstrak metanol daun kecombrang pada konsentrasi 2.5% menunjukkan konsentrasi paling baik dalam menekan pertumbuhan, sporulasi dan perkecambahan konidium C. acutatum dengan keefektifan berturut-turut 66.2%, 99.8%, and 100% dibandingkan perlakuan lainnya. Pengujian secara in vivo pada buah cabai rawit menunjukkan ekstrak metanol daun kecombrang pada konsentrasi 2.5% mampu menghambat pertumbuhan C. acutatum, sedangkan pada konsentrasi 4.8% mampu memperpanjang masa inkubasi, menurunkan insidensi dan keparahan penyakit secara nyata dengan keefektifan berturut-turut 88.4% dan 96% dibandingkan kontrol dan perlakuan lainnya. Aktivitas anticendawan ekstrak metanol daun kecombrang terhadap infeksi C. acutatum disebabkan kandungan senyawa fenol yang tinggi. Penelitian ini membuktikan potensi ekstrak metanol daun kecombrang sebagai fungisida nabati yang mampu menekan infeksi C. acutatum khususnya pada buah cabai rawit pascapanen.

Kitosan dan ekstrak kasar daun bugenvil diketahui mampu mengendalikan beberapa virus tanaman termasuk Bean common mosaic virus strain Blackeye Cowpea (BCMV-BlC). Untuk mengurangi penggunaan bahan baku dan peningkatan keefektifan juga stabilitasnya, kedua bahan perlu disintesis menggunakan teknologi nanpopartikel (NP). Penelitian bertujuan menyintesis nanopartikel kitosan, ekstrak daun bugenvil, dan kombinasinya menggunakan modifikasi metode gelasi ionik, mengarakterisasi NP dan mengevaluasi potensi NP untuk mengendalikan BCMV-BlC pada tanaman indikator Chenopodium amaranticolor. Nanopartikel kitosan (Kit-NP), ekstrak daun bugenvil (EDB-NP), dan kombinasinya (KEDB-NP) berhasil disintesis dengan rata-rata ukuran partikel berturut-turut sebesar 99.72, 163.68, dan 221.42 nm berdasarkan pengamatan di bawah transmission electron microscope (TEM) dan berbentuk bola (sferis) berdasarkan hasil analisis scanning electron microscope (SEM). Hasil analisis fourier transform infrared (FTIR), KEDB-NP menunjukkan gugus fungsi berturut-turut hidroksil, alkena, amina, cincin aromatik, dan senyawa alifatik organohalogen. Daun C. amaranticolor yang diberi perlakuan Kit-NP, EDB-NP, KEDB-NP dan juga non-NP pada konsentrasi 100-800 ppm sebelum inokulasi virus menunjukkan jumlah rata-rata lesio lokal nekrotik (LLN) nyata lebih rendah dibandingkan kontrol tanaman sakit tanpa perlakuan dan tidak berbeda nyata antarkonsentrasi. Perlakuan NP dan non-NP sebelum inokulasi virus secara nyata memperpanjang periode inkubasi dan menekan pembentukan LLN dengan keefektifan 67.5%–100% dibandingkan dengan aplikasi setelah inokulasi virus. Di antara konsentrasi yang diuji, konsentrasi NP antara 100 dan 300 ppm yang diaplikasikan sebelum penularan virus menunjukkan paling efektif dalam menghambat pembentukan LLN. Sintesis EDB-NP, Kit-NP, dan KEDB-NP menggunakan sangat sedikit bahan baku, namun keefektifannya sebanding dengan bentuk non-NPnya dalam mengendalikan infeksi BCMV.

Infeksi virus menjadi salah satu pembatas produksi kedelai di Indonesia. Penelitian bertujuan menguji efektivitas kitosan, ekstrak daun bugenvil, dan kombinasinya, serta insektisida dalam mengendalikan infeksi virus pada kedelai di lapangan. Efektivitas perlakuan diuji dalam petak utama tanpa dan dengan pembatas jagung. Peubah penyakit, populasi serangga, dan peubah agronomi diamati mingguan. Populasi kutudaun pada perlakuan kontrol dengan tanaman pembatas lebih rendah daripada perlakuan kontrol tanpa tanaman pembatas, menunjukkan tanaman pembatas mampu menghalangi kutudaun masuk ke pertanaman kedelai. Inkorporasi perlakuan kitosan, ekstrak daun bugenvil, dan kombinasinya mampu menekan populasi kutudaun sebanding dengan perlakuan insektisida pada kedua petak utama. Area under population progress curve (AUPPC) kutudaun selaras dengan lebih rendahnya area under disease progress curve (AUDPC), insidensi dan keparahan penyakit serta AUDPC secara nyata dibandingkan dengan kontrol tanpa perlakuan. Efektivitas perlakuan pada petak dengan tanaman pembatas mampu menurunkan populasi kutudaun, insidensi dan keparahan penyakit lebih tinggi dibandingkan dengan perlakuan yang sama pada petak tanpa tanaman pembatas. AUDPC antarperlakuan kitosan, ekstrak daun bugenvil, kombinasi, dan insektisida secara umum berbeda nyata lebih rendah pada kedua petak utama dibandingkan dengan kontrol tanpa perlakuan. Hasil panen kedelai menunjukkan lebih tinggi secara signifikan daripada perlakuan kitosan, ekstrak daun bugenvil, dan kombinasinya dibandingkan dengan perlakuan kontrol pada kedua petak utama. Penggunaan tanaman pembatas yang disatukan dengan salah satu perlakuan kitosan dan ekstrak daun bugenvil dapat menjadi paket pengelolaan yang ramah lingkungan untuk mengendalikan infeksi virus pada tanaman kedelai di lapangan.

Penyakit busuk bulir padi yang disebabkan oleh Bulkholderia glumae merupakan penyakit penting yang dapat ditularkan melalui benih padi. Berbagai teknik pengendalian penyakit busuk bulir padi telah dikembangkan untuk mencegah kehilangan hasil panen, salah satunya menggunakan asap cair. Asap cair banyak dikaji sebagai agens pengendalian berbagai penyakit tanaman. Penelitian ini bertujuan menentukan potensi asap cair untuk pengendalian penyakit busuk bulir padi yang disebabkan oleh B. glumae dan sebagai pemacu pertumbuhan bibit padi. Tahapan penelitian terdiri atas: uji potensi asap cair terhadap B. glumae, uji fitotoksisitas asap cair dan pengaruhnya terhadap pertumbuhan benih padi, serta uji keefektifan asap cair dalam menekan B. glumae pada benih terinfeksi. Hasil penelitian menunjukkan bahwa asap cair dengan konsentrasi 2% dapat menekan perkembangan B. glumae secara in-vitro dan tidak menyebabkan fitotoksisitas pada benih padi dengan indeks vigor 90% dan daya berkecambah 90% dibandingkan dengan kontrol dengan nilai indeks vigor dan daya berkecambah sebesar 76% dan 83%. Asap cair dengan konsentrasi 2% juga dapat menekan keparahan penyakit pada fase pembibitan dengan tingkat hambatan relatif 43.8%. Adapun nilai panjang plumula bibit padi pada perlakuan asap cair 2% ialah sebesar 5.87 cm. Nilai plumula tersebut lebih besar dibandingkan dengan kontrol yang hanya sebesar 5.22 cm. Berbeda dengan plumula, nilai panjang radikula tidak mengalami peningkatan signifikan dibandingkan dengan kontrol.

Infeksi Papaya ringspot virus (PRSV) di Indonesia pertama kali dilaporkan pada pepaya di Nangroe Aceh Darussalam pada tahun 2012. Sejak itu, PRSV atau penyakit bercak bercincin pada pepaya menyebar ke beberapa daerah di Jawa, Sumatera, Bali, dan Nusa Tenggara Barat. Penelitian ini dilakukan untuk mengonfirmasi keberadaan PRSV di beberapa daerah penanaman pepaya di Jawa dan mengetahui identitas molekulernya. Metode double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) dengan antiserum spesifik PRSV digunakan untuk mendeteksi sampel dari lapangan. Insidensi PRSV hasil deteksi DAS-ELISA di Bogor, Purworejo, Kebumen, dan Bantul berturut-turut sebesar 59.1%, 51.4%, 84.2%, dan 96.2%. Identifikasi lebih lanjut dilakukan dengan reverse transcription-polymerase chain reaction menggunakan primer spesifik (PRSV326/PRSV800), dilanjutkan dengan sikuensing DNA. Fragmen DNA berukuran 475 pb berhasil diamplifikasi dari sampel lapangan dan analisis nukleotida menunjukkan bahwa semua sampel terkonfirmasi PRSV dengan homologi antarisolat berkisar antara 95.4% sampai 99.4%. Analisis filogenetika menunjukkan bahwa isolat-isolat PRSV di Jawa berada dalam satu grup yang sama dengan isolat PRSV-P pepaya dari Thailand.

Tomato chlorosis crinivirus (ToCV) diketahui berasosiasi dengan penyakit kuning pada tanaman tomat. Infeksi Crinivirus menunjukkan peningkatan di beberapa daerah di Jawa Barat saat ini. Tersedianya varietas tomat tahan akan menjadi cara efektif dalam pengelolaan penyakit virus, namun perlu upaya mencari sumber ketahanan tanaman terhadap infeksi virus. Penelitian bertujuan menentukan tingkat ketahanan 12 galur tomat terhadap infeksi ToCV. Tomat uji berumur 14 hari setelah pindah tanam diinokulasi dengan ToCV menggunakan 10 ekor kutukebul (Trialeurodes vaporariorum) viruliferus per tanaman. Pengamatan dilakukan terhadap peubah penyakit (periode inkubasi, insidensi dan keparahan penyakit, titer virus) dan peubah agronomi (tinggi tanaman, jumlah daun, jumlah dan bobot buah). Rata-rata periode inkubasi berkisar 9.4–13.5 hari, dan insidensi penyakit berkisar 90.9–100%. Gejala visual bervariasi dari klorosis ringan sampai sedang dan daun menggulung ke atas dengan skor keparahan penyakit berkisar 1.0–3.0. Titer virus diukur berdasarkan nilai absorbansi ELISA, yaitu berkisar 0.358–1.122. Secara umum, infeksi ToCV menghambat pertumbuhan tanaman dan menurunkan jumlah daun, menghambat bobot dan jumlah buah berturut-turut sebesar 6.0–37.8%, 8.6–39.5%, 2.7–33.7% dan 7.0–25.5%. Berdasarkan peubah penyakit, respons galur tomat dapat dikategorikan rentan (BISILB#1029A, BISILB#22, dan BISILB#724B), moderat tahan (BISILB#825B, BISILB#60D, BISIKC#402, BISIKC#96D, dan BISILB#40I), dan tahan (BISILB#1372ORA, BISILB#703A, BISILB#703B, dan BISILB#724A). Namun, sifat ketahanan galur tomat tersebut tidak berkorelasi dengan kemampuan produksi tanaman. Oleh karena itu, perlu dilakukan perbaikan sifat ketahanan pada empat galur tersebut agar lebih adaptif terhadap faktor lingkungan budi daya sehingga dapat dimanfaatkan sebagai tetua varietas tomat unggul tahan ToCV.

Utilization of plant extracts to suppress Squash Mosaic Virus Infection on ridged gourd (Luffa acutangula [L]. Roxb). Control effort strategies against plant pathogens are necessary to be explored and evaluated its effectiveness intensively. One environmentally friendly control method is biological control by using plant extracts. It is well known that cucurbits are cultivated widely in Indonesia. However, cucurbits are susceptible plants against various pathogens, including viruses. Recently, Squash mosaic virus (SqMV) found to infect cucurbits such as ridged gourd in West Java. The research aimed to explore and evaluate the effectiveness of plant extracts to suppress SqMV infection on the ridged gourd. Three selected plants, namely Bougainvillea spectabilis, Mirabilis jalapa, and Celosia cristata, were tested in greenhouse trial with aspirin as a comparison. The extract was sprayed on the leaves a day before mechanical virus infection. The disease assessments and agronomic parameters were observed. The plant extract treatment showed able to prolonged the incubation period, caused milder symptoms, reduced the virus titer, and showed better plant growth in compared with aspirin treatment or untreated control. B. spectabilis and M. jalapa crude leaf extract revealed able to suppress the SqMV infection with comparable effectiveness with relative inhibition level of disease severity and virus titer up to 48.2% and 80.6 to 81.4%, respectively, indicating their potential as biocontrol for SqMV.

White tip disease on rice caused by Aphelenchoides besseyi is categorized as emerging infectious disease in Indonesia because the disease incidence and its geographical distributionare increasing rapidly. Until presently, there is no information related with mass culture technique of Ap. besseyi in Indonesia. Thus, studies to obtain pure population of Ap. besseyi are necessary to be conducted to support various research aspects in the future. This research is aimed to study Ap. besseyi pure mass culture technique by rearing the nematode on three fungal species. Three different fungal cultures on PDA medium, i.e. Alternaria padwickii, Fusarium semitectum, and Botrytis cinerea were tested as Ap. besseyi cultivation media. To obtain the optimum condition for nematode cultivation, the fungal cultures were incubated in three different temperature. The nematodes were surface sterilized with 0.1% streptomycin sulfate followed by washing with sterilized water before infesting the nematode into fungal culture. Subsequently, 25 sterilized nematodes were infested into 7 days old of fungal culture and incubated at 20ºC, 25ºC and 30 ºC. After 21 days, nematodes were harvested and counted the final population. Among fungal species tested as rearing medium, the best culture for Ap. besseyi reproduction was on Al. padwickii culture at 25 ºC with average final population up to 9,115 per petri dish and reproduction factor 364.6. At a 30ºC, Ap. besseyi was failed to develop its population in all the fungal cultures tested. It indicated that the optimum temperature for reproduction of Ap. besseyi on those of fungal species was 20-25 ºC.

Potato is one of economically important crops in Indonesia. However, its production fluctuates since there are some factors affecting the yield. Recently, we found dwarf disease at potato central production area in Wonosobo and Banjarnegara Regencies in Central Java. So far, there is no information related to the yield loss caused by the dwarf disease on potato. Therefore, the research aimed to estimate the yield loss caused by the dwarf disease on potato in Central Java. The yield loss estimation was determined on some potato cultivations with different disease severities. The disease intensity was observed for five times with interval two weeks on six plots. The quantity and quality of potato yields, and selling price was calculated at the end of the observation and the correlation between the severity of disease and AUDPC (Area under disease progress curve) with yield loss was determined by regression and correlation analysis. The dwarf disease reduced plant height, individual and total tuber weight without affecting the number of tuber yield. The different of disease intensities in some area affected to the percentage of yield loss. The yield loss caused by dwarf diseases on individual potato plants up to 64.42%. Yield loss estimation caused by the dwarf disease in fields with different level of disease intensities ranged from 10.3526.43%. Regression analysis between disease severities and yield losses showed the R square value at the level of 88.6% and a correlation at the level of 94.14%. These results indicated that the correlation between the severity of dwarf disease and yield loss is high.

One effort to increase domestic sugar production is through the extension of sugarcane growing area outside Java island. The status of sugarcane disease outside Java, particularly those caused by virus(es), has not been evaluated yet; where virus diseases are able to decrease sugarcane productivity. Therefore, the aim of this research was to identify the sugarcane major viruses and their distributions in Lampung and South Sulawesi. Field survey and leaf sampling was collected from Lampung Tengah District, in Lampung Province and three districts in South Sulawesi Province i.e., Bone, Gowa, and Takalar. Virus detection was performed by reverse transcription-polymerase chain reaction (RT-PCR) method using specific primers for Sugarcane mosaic virus (SCMV), Sugarcane streak mosaic virus (SCSMV), and Sugarcane yellow leaf virus (SCYLV). Results indicated that symptoms variation was observed in the field. The highest disease incidence and severity was found in Lampung, i.e. 100% and 61.6771.67%, respectively; whereas the lowest disease incidence and severity was found in Takalar, i.e. 570% and 545%, respectively. The disease incidence and severity of viral diseases tend to be low in dry and low rain fall conditions. This information might be helpful for the extensification program of sugarcane development in supporting the sugar self-sufficiency program.

A survey on several cucumber cultivation areas in West Java, Central Java, Yogyakarta, and East Java found many plants showing typical Begomovirus symptoms such as yellow mosaic, cupping, and vein banding. This study was aimed to determine disease frequency, detection and molecular characterization of the causal virus of those symptoms on cucumber in Java. Sampling was conducted by purposive sampling by collecting 50 symptomatic plants from each location in West Java (Indramayu, Subang, and Bogor), Central Java (Brebes and Klaten), Yogyakarta (Kulon Progo), and East Java (Nganjuk, Kediri, and Tulungagung). The detection and disease frequency was determined based on DIBA test using a specific antiserum of Tomato leaf curl New Delhi virus (ToLCNDV) and Squash leaf curl virus (SLCV). The identification of nucleic acid was conducted by PCR using specific primer of ToLCNDV and SLCV, DNA cloning, and sequencing. The results of serological detection showed the disease frequency of ToLCNDV and SLCV ranged from 92.77-100% and 78.33-93.3%, respectively. PCR using specific primer of ToLCNDV successfully amplified the coat protein gene at a size of 600 bp from all samples. Homology nucleotide and amino acid sequences among ToLCNDV Java isolate ranging from 95.6-99.2% and 99.7-100%. ToLCNDV isolates Java had highest nucleotide and amino acid sequences similarity with cucumber isolate from Klaten, Indonesia (AB613825) ranging from 96.1-98.1% and 99.7-100%, and was considered as “Indonesia” strain. SLCV not amplified on all samples by PCR using specific primer, indicating it might not present yet on cucumber in Java.

Gejala tulang daun kuning (vein yellowing) dan malformasi daun yang diduga disebabkan oleh virus ditemukan pada ubi jalar IR Melati di daerah Kendalpayak, Malang, Jawa Timur. Amplifikasi DNA/cDNA menggunakan primer universal Begomovirus, Potyvirus, dan Cucumovirus menunjukkan positif teramplifikasi DNA dengan primer universal Begomovirus, dan Potyvirus, namun negatif dengan primer universal Cucumovirus. Berdasarkan runutan sikuen nukleotida, gejala tulang daun kuning dan malformasi daun disebabkan oleh infeksi ganda Pepper yellow leaf curl virus (PYLCV) dan Sweet potato virus C (SPVC). Analisis identitas DNA dengan perangkat lunak BioEdit menunjukkan homologi paling tinggi sebesar 98.5% terhadap PYLCV isolat cabai dari Bangli Bali, dan sebesar 98% terhadap SPVC dengan isolat ubi jalar asal Jepang dan Amerika Serikat. Laporan ini merupakan temuan baru infeksi alami PYLCV dan SPVC pada ubi jalar di Indonesia.

Sugarcane streak mosaic virus (SCSMV) is an important virus causing mosaic disease in sugarcane and transmitted through the cutting cane. Commercial antiserum to detect SCSMV and to monitor the disease development is not available. The research was conducted to produce antigen of SCSMV coat protein (SCSMV-CP) through overexpressing it on bacterial expression which will be used for antiserum production. SCSMV-CP was amplified using specific primers for CP gene containing BamHI and HindIII restriction enzyme sites and cloned into pTZ57R/T. Subsequently, the SCSMV-CP was subcloned into pET28a and transformed on Escherichia coli BL21(DE3) and Rosetta-gami(DE3)pLysS. The concentration of isopropyl β-d-thiogalactopyranoside (IPTG), incubation temperature, and bacterial harvesting time after IPTG induction were optimized. SCSMV-CP gene was successfully amplified with size ±855 bp, subcloned into vector expression, and expressed in insoluble fraction either in both bacterial host. Optimal protein expression of SCSMV-CP recombinant was obtained at 25°C with IPTG concentration 0.25–1.00 mM and harvested at 9–12 hours after IPTG induction in E. coli BL21(DE3), and at 30°C with IPTG concentration 0.25–1.00 mM and harvested 3–12 hours after IPTG induction in E. coli Rosetta(DE3)pLysS. SDS-PAGE analysis showed that protein size of SCSMV-CP recombinant was ±35.4 kDa.

Molecular identification Broad Bean Wilt Virus 2 (BBWV2) and Cymbidium Mosaic Virus (CymMV) from patchouli plant (Pogostemon cablin Benth.). Several viruses have been reported to be associated with mosaic disease on patchouli plant in Indonesia. This study aims to identify the two viruses in patchouli cultivation in West Java by studying the molecular characterization. Mosaic symptomatic leaf samples taken from patchouli cultivation in Manoko (Bandung Barat District, West Java Province). RNA extraction was performed using Xprep Plant RNA mini kit. RNA amplification with RT-PCR technique using primers for the cp gene region of BBWV2 and CymMV. The PCR product was sent to PT. Science Genetics Indonesia to do sequencing, then analyzed nucleotide sequences. Results of RT-PCR were performed successfully obtained DNA bands with size accordance with the predictions of the primer design for BBWV2 and CymMV cp region. Further, based on nucleotide and amino acid sequence analyses, the two virus isolates were confirmed as BBWV2 and CymMV respectively. Phylogenetic analyses revealed that BBWV2 Manoko clustered with BBWV2 from Singapore (original host of Brazilian red-cloak), China (pepper) and South Korea (chili). Whereas, CymMV Manoko become one cluster with CymMV from India (Phaius sp.), Indonesia (Dendrobium), China (vanilla), Thailand (Oncidium), Hawai (Dendrobium) and South Korea Cymbidium).

Molecular identification of bean common mosaic virus associated with yellow mosaic disease on yard long bean. Bean common mosaic virus (BCMV) has been reported as one of the causal agents of yellow mosaic disease on yard long bean in West Java and Central Java. Infected plants showed mosaic, yellowing, and mixture of yellow mosaic. The research was conducted to identify the diversity of BCMV associated with yellow mosaic disease based on coat protein (CP) gene sequences. Symptomatic leaf samples were collected from yard long bean growing areas in several districts in West Java (Bogor, Cirebon, Subang, and Indramayu), and several districts in Central Java (Tegal, Klaten, Solo, Yogjakarta, Sleman, and Magelang). Molecular detection using RT-PCR method was carried out by using specific primer to BCMV which will amplify the CP gene. DNA fragment, + 860 bp in size, was successfully amplified from 8 out of 13 leaf samples, i.e samples from three villages in Bogor District (Cangkurawok, Bubulak, Bojong), and five samples from District of Cirebon, Subang, Solo, Sleman, and Tegal. Sequence analysis of those DNA fragment showed that 4 isolates (Bogor-Cangkurawok, Subang, Solo and Sleman) had the highest homology to BCMV-BlC from Taiwan, whereas 2 isolates (Cirebon and Tegal) had the highest homology to BCMVNL1 from England. Further, phyllogenetic analysis revealed that those of 4 isolates were closely related to BCMV-BlC from Taiwan based on nucleotide as well as amino acid sequences; while those other 2 isolates were closely related to BCMV-NL1 from England based on nucleotide sequences but closely related to BCMV-BlC Y from China based on amino acid sequences. Phyllogenetic analysis showed that those of 6 BCMV isolates separated in two different clusters; 4 isolates (Bogor- Cangkurawok, Subang, Solo, and Sleman) in cluster 1 together with BCMV-BlC from Taiwan, while other 2 isolates (Cirebon and Tegal) in cluster 2 together with BCMV-NL1.

Moleculer Characterization of Papaya ringspot virus type P on Cucumber in JavaInfection of Papaya ringspot virus (PRSV) on cucumber plants showing mosaic symptom was detected using specific antibody. Further investigation was conducted to determine molecular characters and status of PRSV infecting cucumber in Java. Infection of PRSV was detected from leaf samples collected from the field using dot immunobinding assay (DIBA). Disease frequency caused by PRSV infection reached 81.11%, 95.86%, 91.66%, and 92.3% in East Java, Central Java, Yogyakarta, and West Java, respectively. Characterization of PRSV isolates was conducted by reverse transcription polymerase chain reaction (RT-PCR) using specific primers for PRSV-P and PRSV-W, followed by cloning, and DNA sequencing. DNA fragment of 470 bp was successfully amplified using specific primers for PRSV-P from several samples from Nganjuk, Brebes, Kulon Progo, and Subang; but no amplification was achieved using specific primers for PRSV-W. Nucleotide and amino acid analysis showed high homology among PRSV-P isolates from Nganjuk, Brebes, Kulon Progo, and Subang, i.e. 98.6%-99.7% and 99.3%-100%, respectively. This is an indication of a low genetic variation among PRSV-P from Java. Further phylogenetic analysis indicated that PRSV-P isolate cucumber is in the same cluster with PRSV-P isolate papaya from Bali, Indonesia. This is the first report of PRSV-P infecting cucumber in Indonesia.

Yellow Spot Disease on Sweet Potato in Bogor, West JavaYellow spot symptom on sweet potato red cultivar was observed in Cikarawang and Leweung kolot area, Bogor regency. Symptomatic leaf samples gave positive reaction in serological detection by DIBA method using polyclonal antiserum for Potyvirus. DNA fragment of ± 700 bp in length was successfully amplified by RT-PCR using degenerate primer for cylindrical inclusion gene (CI) of Potyvirus. Further nucleotide sequence analysis indicated high homology to Sweet potato feathery mottle virus (SPFMV). The homology of SPFMV Cikarawang (Crkw) isolate ranging from 89–98% to several isolates from other countries with the highest homology to Japan and Spain isolates. SPFMV Crkw isolate was in the same cluster with the Japan and Spain isolates based on phylogenetic analysis of both nucleotide and amino acid sequences. This is the first report of SPFMV on sweet potato in Bogor, West Java, Indonesia.

Carnation has a highly economic demand of cut flower in Indonesia. Field observations in West Java Indonesia was conducted in order to find the typical mottle symptoms that was a suspect caused by a virus disease. Identification of the virus was respectively conducted by performing ELISA test with four anti sera and characterizations held by bioassay, observing of virion particles, detecting of nucleic acid by RT-PCR and nucleotide sequencing. Total of 403 samples were collected from plants with or no virus-like symptoms. Among those all tested, 83% were found to be infected by Carnation mottle virus (CarMV), but negatively against Carnation ringspot virus (CRSV), Carnation laten virus (CLV), and Carnation vein mottle virus (CVMV) antisera. By mechanical inoculation, the virus was able to infect systemically Cenopodium quinoa and locally infect on others. However on Phalaenopsis sp and Gomprena globosa, there was symptompless found. The isometric CarMV particles size was approximately 30 nm. RT-PCR using specific primers of CP gene of CarMV successfully amplified a DNA sized 1000 bp. CarMV West Java Indonesian (Idn-WJ) isolates possessed the highest nucleotide and amino acid homology with CarMV from Spain and was in the same cluster with CarMV from China, Taiwan and Israel.

Cucumber mosaic virus strain soybean (CMV-S) is one of economically important virus infecting soybean in Indonesia. However, it is very few information related with the CMV-S Indonesia isolates. Thus, the aim of present work is to detect and identify CMV-S isolates from different origin. Leaf samples collected from six different soybean fields in Java and North Sumatera. Molecular detection was carried out by reverse transcription polymerase chain reaction (RT-PCR) using specific primer of the coat protein (CP) gene and DNA sequencing. RT-PCR were successfully amplified the entire CP gene size ~657 bp from all samples and encoded 218 amino acids. Analysis of nucleotide and amino acid sequences showed high homology among isolates ranging from 99.5% and 100%. However isolate from Sindang Laut either nucleotides or amino acids showed lower homology to that of five isolates ranging from 89.4%-89.6% and 91.7%, respectively. The differences between CMV-S with other non legume strain found in six amino acid positions in the CP gene, suggesting the differences might related with host specificity. Phylogenetic analysis of amino acid of six isolates to other CMV strain showed that the five CMV-S isolates were in the same cluster, while Sindang Laut isolate was in different cluster together with the non-legume CMV from India. It is indicating the present of genetic variability among CMV-S isolates in Java.

Bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae is one of the major problems in rice production in Indonesia. One of the control measures for the disease is by the utilization of endophytic bacteria. This study was aimed to determine the ability of endophytic bacteria isolated from the roots, stems and leaves of rice in inducing plant resistance to bacterial leaf blight on rice. Screening of endophytic bacteria showed that 370 isolates have good viability and have different colony morphology. Among them, 7 isolates were able to induce resistance and 1 isolate was able to promote the growth of rice in the nursery. However, only 8 isolates did not cause hypersensitive reaction on tobacco plants. The selected isolates of endophytic bacteria were further examined for their ability to induce resistance of rice in greenhouse experiments. Observation involved several variables, i.e. PR1 and PBZ1 gene expression, peroxidase enzyme activity, incubation period, and disease progression. Seven isolates of endophytic bacteria were able to induce PR1 and PBZ1 gene expression, 4 isolates were able to increase peroxide enzyme activity, 4 isolates could prolong the incubation period, and 2 isolates can inhibit the development of disease. However, only EB4 451 isolate was consistently able to induce PR1 and PBZ1 gene expression, increased peroxide enzyme activity, prolonged incubation period, and suppressed the progression of the disease. The EB4 451 isolate was identified based on nucleotide sequence as Bacillus subtilis.

Utilization of chitosan to control Bean common mosaic virus (BCMV) on yard long bean. Bean common mosaic virus (BCMV) is one of important viruses infecting yard long bean in Indonesia. One of efforts to control its infection is by utilizing chitosan. Thus, the aim of the conducted research was to test the effectiveness of chitosan in controlling BCMV on yard long bean. Concentration of chitosan tested were 0.1% and 1.0% and it was applied as seed treatment (PB), leaf spraying before (SB) and after (ST) mechanical inoculation of BCMV. Incubation period, disease incidence and severity, peroxidase enzyme activity, and BCMV titer were measured as observation parameters. Incubation period of all treated plants were longer as compared with untreated control plants. Symptoms of treated plants at concentration 0.1% (SB and ST) showed mild to severe symptom and leaf malformation, while at concentration 1.0% showing milder symptoms and some of tested plants remain symptomless. Treated plants showed lower peroxidase enzyme activity and significantly lower BCMV titer as compared with that of untreated control plants. The lowest to highest percentage of virus inhibition exhibited by ST0.1, SB0.1, PB0.1, PB1, SB1 and ST1 treatments with virus relative inhibition level ranged 75.94%-86.07% and severity inhibition level ranged 39.55%-64.63%.

ABSTRACT Antivirus actitivity of several plant extracts against Bean common mosaic virus strain Black eye cowpea (BCMV-BlC) on Yard long bean. Bean common mosaic virus (BCMV) is an important virus on yard long bean and it is difficult to control. One of control effort way by utilizing antiviral substances of plant origin. The research was done to select and test the effectiveness of plant extracts in suppressing BCMV infection on yard long bean. Twenty two plant extracts were selected by (1) spraying the crude extract to Chenopodium amaranticolor leaves, then plant inoculated by BCMV 1 hour after spraying, and (2) mixturing the crude extract with sap containing BCMV, then inoculated mechanically to C. amaranticolor. Local necrotic lesion number and inhibition percentage are measured. All plant extract treatments were able to reduce Necrotic lokal lesion formation significantly compared to untreatment control. Further, fifteen plant extracts were selected to test their effectiveness in controlling BCMV on yard long bean in green house trial. The results showed that except geranium and red ginger treatment, other extract treatments were able to reduce significantly the disease incidence and severity, symptoms, and BCMV titer, respectively. Among tested extracts, Bougainvillea spectabilis, Mirabilis jalapa, and Celosia cristata are the most effective crude extracts in suppressing BCMV infection.

Polymerase chain reaction (PCR) is an important tool for detection, identification and monitoring of quarantine pests in Indonesia. DNA isolation method from target organism is an important step to provide adequate DNA template for performing PCR. Objective of the research was to compare conventional, commercial kit, FTA-card and its modification methods of DNA isolation to be used in PCR detection for Colletotrichum acutatum and Peronosclerospora sorghi from chili and maize, respectively. DNA obtained from various isolation methods were measured using UV-vis nanodrop-spectrophotometry. DNA amplification was performed using DNA concentration of 15 ng µL-1 from each isolation method with gradual primer concentrations of 0.4; 0.6; 0.8; and 1.0 mM. The highest concentration of DNA was achieved with conventional methods for C. acutatum from pure culture and P. sorghi from maize leaf. Best DNA purity was obtained from isolation method using commercial kit for C. acutatum from infected fruit (1.94) and from conventional method for C. acutatum from pure culture (1.91). The highest total yield of isolated DNA was achieved by modified FTA-card for C. acutatum from pure culture. In general DNA amplification using various primer concentration gave positive results although DNA bands intensity was varied from faint to very bright. Furthermore PCR optimization using the best primer concentration from previous reaction showed that all DNA templates resulted in thick and bright DNA bands.

Recently, field surveys were conducted in several orchid nurseries in Bogor (West Java), Magelang (Central Java) and Malang (East Java). We found that most of the commercially orchids sampled from Bogor was infected by virus-like disease. The symptoms depend on the orchid species. Thus, the symptoms varied such as mottle, mosaic and necrotic flecks either on the leaves or on the flowers. Similiar symptoms were not found in samples obtained from Central Java and East Java. A Tobamo-like virus was inferred to be possible cause of the viral disease-like symptoms. Serological test of the samples by ELISA showed positive against Odontoglosum Ringspot Virus (ORSV) antibody and was negative against Cymbidium Mosaic Virus (CyMV) antibody. Total RNA was extracted from symptomatic plants and RT-PCR was carried out by using a pair of coat protein (CP) gene primer of ORSV. It was successfully amplified a 500 bp of DNA fragment and it was directly sequenced. The nucleotide sequence of CP gene had confirmed the identity of ORSV. Phylogenetic analysis based on the CP nucleotide sequences were grouped into only one major cluster. The ORSV isolate from Bogor (Sd 21) and the other isolates were clustered in the same group and had highest nucleotide homology (99%). These results provide first evidence of ORSV infecting orchids in Bogor, Indonesia.

During 2008 crop season, an outbreak of severe yellow mosaic disease on yard long bean (Vigna unguiculata subsp. Sesquipedalis) occurred in several farmers’ fields in West Java. Yard long bean var. Parade inoculated manually with extracts from symptomatic leaves showed the symptoms indicating the presence of virus. Symptomatic leaf samples tested positive in enzyme linked immunosorbent assay (ELISA) with antibodies to group specific Potyvirus and Cucumber mosaic virus (CMV). Total RNA derived from symptomatic leaves was subjected to reverse transcription-polymerase chain reaction (RT-PCR) using primers specific to the cylindrical inclusion (CI) protein of potyviruses and CMV coat protein (CP) specific primers. Pair wise comparison of sequences obtained from cloned RT-PCR products with corresponding nucleotide sequences in the GenBank confirmed the presence of Bean common mosaic virus strain Blackeye (BCMV-BlC) and CMV in the symptomatic beans. Sequences of BCMV and CMV isolates from the beans showed maximum nucleotide sequence identities (92-97%) and (90%), respectively with BCMV-BIC and CMV isolates from Taiwan. Each virus isolate also clustered closely with corresponding isolates from Taiwan in a phylogenetic analyses. These results provide first evidence of the occurrence of multiple infection of BCMV-BIC and CMV in the yard long been from Bogor, West Java.

Tobacco Mosaic Tobamovirus (TMV) is one of many important viruses infecting Solanaceous plants including hot pepper in Indonesia. To accomplish and improve the effectiveness of virus management, we used root-colonizing bacteria (rhizobacteria) isolated from healthy hot pepper. Eight rhizobacteria isolates were selected and their capacity in enhancing plant growth and inducing systemic resistance (ISR) against TMV in greenhouse trials were evaluated. The rhizobacteria was applied as seed treatment and soil drench. Bacterized-seedling showed a better growth vigor, fitness and a milder symptom than non-bacterized control plants. The protective effect of rhizobacteria was more pronounced after challenging inoculation by TMV, especially for plants treated by isolates I-6, I-16, and I-35. However, TMV accumulation was slightly affected by bacterial treatment. The rhizobacteria might improved ISR by increasing peroxidase enzyme activity but this depends on the species. Based on whole results, isolate I-35 was the potential plant growth promotion rhizobacteria (PGPR). The I-35 was identified as Bacillus cereus based on morphological characteristics and nucleotide sequences of 16S r-RNA.

Aphis craccivora is one of the important pests on yard long bean. It causes direct damage and also has an indirect effect as insect vector of the Bean common mosaic virus (BCMV). The research was done to test the effectiveness of chitosan in suppressing aphid population growth, feeding preference and its ability in transmiting BCMV. Chitosan with concentration ranging of 0.1–1.0% were applied on leaves using spraying method at 1 day before BCMV transmission. BCMV was transmitted by using 3 individuals of viruliferous aphids on each plant. Results show that chitosan treatments on leaves or plants significantly suppressed the population and feeding preferences of A. craccivora. Further, treated plants showed lower disease incidence, severity and BCMV titre significantly compared with untreated control plants. The positive effects of chitosan in suppressing population growth as feeding preferences and BCMV transmission might be due to the anti-feedant effect of chitosan on A. craccivora. Based on the result, chitosan at concentration 0.9% is the most effective concentration in suppressing BCMV and its vector A. craccivora.

Erwinia chrysanthemi (currently Dickeya sp.) is one of the A2 quarantine pest that must be concerned of its distribution on potato in Indonesia. The aim of this study is to detect and identify E. chrysanthemi from potato in Java. A total of 400 samples of potato plants showing symptoms of soft rot were obtained from several potato areas in Pangalengan and Garut (West Java), Dieng (Central Java), and Batu-Malang (East Java). Disease incidence was determined by indirect enzyme-linked immunosorbent assay (I-ELISA) using polyclonal antiserum. E.chrysanthemi was isolated from plant samples with positive ELISA results. Furthermore, bacterial isolates were characterized by GEN III OmniLog ID System and PCR using specific primers Ec3F/Ec4R, as well as the universal 16S rRNA primer pair of 27F/1429R. The incidence of E. chrysanthemi based on ELISA was obtained. Based on physiological characters; Gram, catalase, oxidase, and oxidation-fermentation, there were 4 isolates similar to the genus of Erwinia. However, the results of Gen III OmniLog System, PCR, and nucleotide sequences analysis of 16S rRNA confirmed that none of the isolates were identified as E.chrysanthemi. Otherwise, those 4 isolates were identified as Pseudomonas oryzihabitans, Pantoea agglomerans, and Pseudomonas viridiflava. The result of this study indicated that the existence of E. chrysanthemi as an A2 quarantine pest on potato in Java can not be confirmed and remains as an A1 quarantine pest.

Virus infection is an important production constraint for soybean. Research was conducted to detect virus infection from soybean samples collected from several locations in Java. Leave samples from 50 plants was taken randomly from each location in Bogor, Cirebon, Bantul, and Ponorogo. Field symptoms was observed and disease incidence was determined based on serological assay using specific antibodies to Cucumber mosaic virus (CMV), Soybean mosaic virus (SMV), Cowpea mild mottle virus (CPMMV), and Bean pod mottle virus (BPMV). Incidence of CMV, SMV, and CPMMV was 72–84%, 14–24%, and 6–8%, respectively; whereas infection of BPMV was not found. Specific viral DNA of CMV, Potyvirus, and Geminivirus was successfully amplified using specific primer for CMV coat protein, universal primer for Potyvirus and Geminivirus, respectively. Nucleotide sequence analysis showed that isolate CMV from soybean has the highest homology (99%) to CMV strain S, Potyvirus isolates has the highest homology (90%) to BCMV isolate Mungbean from China and BCMV strain Blackeye from Vietnam, and Geminivirus isolates has the highest homology (96%) to Pepper yellow leaf curl virus (PYLCV) from Bogor and Java. Phyllogenetic analysis showed that CMV strain S formed

Recently, a mosaic disease was observed on jack bean cultivation in Dramaga, Bogor,West Java. The symptom on infected plants, i.e. combination of pale and dark green area was more obvious on young leaves. Vein banding, leaf malformation, and growth inhibition was also observed in infected plants. The symptom was not very obvious in older leaves. Serological detection gave positive reaction to Bean common mosaic virus (BCMV) antiserum, but reaction was negative when detected using specific primer to coat protein (CP) of BCMV strain black eye by reverse transcription polymerase chain reaction. DNA fragments were successfully amplified by RT-PCR using universal primer of CP gene and degenerated primer for cylindrical inclusion gen (CI) of Potyvirus. DNA analysis showed the highest homology (86.4–91.5%) to several isolates of BCMV-infecting different crops from several countries based on partial sequence of CP, whereas based on partial sequence of CI the highest homology (87.3%) was to BCMV-RU1-P. This is the first report of BCMV infection on jack bean in Bogor, West Java, Indonesia.

Bean common mosaic virus (BCMV) is one of the most important virus infecting yard long bean because it can decrease yield and seed transmitted. The aims of research were to determine the effect of plant age infected by BCMV on seed transmission efficiency of the virus, as well as its effect on plant growth. BCMV was mechanically inoculated on yard long bean at 1, 2, 3, and 4 weeks after planting (WAP). Observation was conducted for incubation period, disease incidence and severity, seed transmission efficiency of the virus, plant height, and productivity of the plants. Virus infection was detected using indirect ELISA method. The results showed that the earlier infection of BCMV occurred the shortest incubation period, the most severe symptoms, the highest inhibition of plant growth, and productivity. Disease severity was 94.6, 83.8, 81.1, and 69.6% on plants inoculated at 1, 2, 3, and 4 WAP, respectively. Disease incidence and virus titer was not affected by infection on different plant age. Seed transmission of BCMV was 7, 66, 39, and 24% on plants inoculated at 1, 2, 3, and 4 WAP, respectively. Infection on 2 WAP was considered the critical times for BCMV to be seed-borne on yard long bean.

Typical viral symptoms including chlorotic and uneven interveinal yellowing on leaves without leaf malformation was observed on sweet potato field in Tana Toraja, South Sulawesi. To identify the causal of the disease, reverse transcription-polymerase chain reaction (RT-PCR) and DNA sequencing were carried out to detect the virus from infected plants. RT-PCR using universal primer for C1 gene of Potyvirus was successfully amplified approximately 683bp DNA fragment. The nucleotide sequences of this C1 gene fragment showed 98% homology to Sweet potato virus G (SPVG). Amplification using specific primer for coat protein (CP) gene of SPVG followed by DNA sequencing confirmed the association of SPVG from infected plants. Further nucleotide analysis shwowed that SPVG isolate from Tana Toraja had 99.2% homology to isolate from Japan. This is the firstt report of SPVG infection on sweet potato in South Sulawesi.

Bean common mosaic virus (BCMV) is one of major virus infecting legumes and is difficult to manage. Utilization of plant extracts as systemic resistance inducer against virus is needed to study. The aim of the research is to evaluate the potency of five leaf extracts, i.e. from pagoda flower, spiny amaranth, four o’clock flower, Chenopodium amaranticolor, and herba andrographitis against BCMV. The effectiveness of leaf extracts were tested by spraying yard long bean leaves. Plants treated by spine spinach shown varied symptoms, while other treatments showed mild mosaic up to symptomless. The highest to lowest of disease incidence was showed by crude leaf extract of spine spinach (70%), four o’clock (10%), herba andrographitis (10%), while C. amaranticolor and pagoda are still uninfected. These results had positive correlation to disease severity and virus inhibition. Four of five tested leaf extracts, except spine spinach, showed their potency as systemic resistance inducer against BCMV. Key words: BCMV, plant extract, yard long bean

Sugarcane streak mosaic virus (SCSMV) is a new emerging virus infecting sugarcane in Indonesia. The virus can be found almost in every sugarcane plantations in Java and it was known as sett-borne virus. Attempt to get virus-free seedling meet difficulties due to lacking an easy, and accurate detection method. SCSMV antiserum is not available yet commercially. Nucleic acid detection by RT-PCR also hampered difficulties in releasing RNA virus from sugarcane tissues. Here we reported the simple direct tube method with minor modification as the convenient way to provide total RNA template from infected sugarcane leaf, stalk and sheath for RT-PCR detection of SCSMV.Key words: RNA extraction, RT-PCR, SCSMV, tube PCR

Anthracnose (Colletotrichum gloeosporioides) is an important disease infecting fleshy fruits. The efficacy of chitosan to suppress C. gloeosporioides infection and its ability to increase the length of fruit storage was evaluated. C. gloeosporioides was isolated and purified from mature papaya. Chitosan was mixed in the potato dextrose agar, and sprayed on the surface of papaya fruit with the concentration of 0.05, 0.1, 0.25, 0.5, 0.75 and 1%. It showed that chitosan concentration of 0.75-1% inhibited C. gloeosporioides growth in vitro up to 72.17-85.21%. Application of chitosan on fruit at concentration of 0.25% suppressed the disease incidence and severity; whereas chitosan concentration of 0.75% was able to suppress the disease incidence, severity, and increase the length of fruit storage twice longer than control. Key words: anthracnose, chitosan, Colletotrichum gloeosporioides, papaya, the length of storage.

Turnip mosaic virus (TuMV) is an important seedborne virus that infects vegetable crops, especially Brassicae group, in Indonesia. Reliable detection method having high accuracy is required to detect the virus from seeds in order to avoid disease incidence as early as possible. A study was conducted to evaluate three total RNA extraction methods from Brassica seeds for TuMV detection using reverse transcription- polymerase chain reaction. The samples used are Brassica rappa seeds and seedling germinated for 3, 5, and 7 days. Total RNA extraction methods evaluated consisted of Wylie method, Randles method, and commercial kit as comparation. Total RNA extracted using Wylie and Randles methods has high concentration but low level of purity, on the other hand total RNA obtained using commercial kit has low concentration but high level of purity. Detection of TuMV from seed was successfully carried out using Wylie and Randles methods, TuMV from 3 - day old seedlings was detected using all three methodes, TuMV from 5-day old seedlings was only detected using Randles method, whereas TuMV from 7-day old seedlings was not detected using all three methodes. Total RNA extraction method using Wylie and Randles methodes is recommended for detection of TuMV from caisin seed using RT-PCR technique. Key words: Brassica rappa seed, reverse transcription- polymerase chain reaction, Total RNA, Turnip mosaic potyvirus