Gede Suastika

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.

Kajian Plant Growth Promoting Rhizobacteria sebagai Agens Proteksi Cucumber Mosaic Virus dan Chilli Veinal Mottle Virus pada Cabai

This study was conducted to evaluate the effectiveness of plant growth promoting rhizobacteria (PGPR) in protecting chillipepper plant from infection of cucumber mosaic virus (CMV) and chilli veinal mottle virus (ChiVMV). Seven isolates of PGPR, i.e. BC1, BTP2H, BTP3G, BTP3O BTP1, BTP2D, and T1F were applied as seed treatment and soil drench. Plants height, number of branch, and fruits weight were measured every one and ten weeks after virus inoculation. Virus concentration in plants and disease incidence were confirmed by enzyme-linked immunosorbant assay (ELISA). Results showed that inoculation with PGPR improved the seed germination. Eight days after sowing, the percentage of PGPR treated seed germination reached 50-84%; whereas those of untreated seed reached only 18%. In general, PGPR treatment significantly reduced (p < 0.05) the effect of virus infection on plant growth. Two PGPR isolates, i.e. BTP1 and BTP2H, maintained fruit weight of infected plants as good as those of healthy plants. Based on ELISA, PGPR was able to inhibit the disease incidence. The BTP3O and BTP2D isolates even protected the plant from ChiVMV infection. Concentration of salicylic acid and peroxidase were relatively higher on plants treated with PGPR than those without PGPR treatment. This gave an indication that PGPR may act as induction agents for systemic acquired resistance. Therefore, PGPR treatment is a promising strategy to control viral diseases on chillipepper.

PENGARUH INFEKSI VIRUS MOSAIK TERHADAP PRODUKSI DAN KADAR MINYAK TIGA VARIETAS NILAM

Purwoceng ( Pimpinella pruatjan Molk.) berkhasiat aprodisiak dengan bahan aktif antara lain steriod, saponin dan ber-gaptin. Penelitian dilakukan di KP. Gunung Putri, bertujuan untuk menge-tahui hubungan cekaman defisit air dengan pembentukan bahan aktif penting pada purwoceng. Pada kegiatan penelitian ini dilakukan dua pengujian yaitu respon pembentukan bahan aktif terhadap peningkatan level cekaman defisit air pada tiga fase pertumbuhan tanaman (3, 5, dan 7 bulan), dan kandungan bahan aktif purwoceng pada kondisi tingkat ketersediaan air tanah di level 80% kegiatan lapang (KL), 60% KL, 50% KL, dan 40% KL, dengan meng-gunakan rancangan acak kelompok, 6 ulangan, pada intensitas cahaya 55%. Hasil penelitian menunjukkan bahwa periode cekaman defisit air berpengaruh terhadap pembentukan bahan aktif pur-woceng. Periode cekaman defisit air 21-38 hari berpengaruh terhadap kandung-an bahan aktif steroid, saponin dan bergapten. Periode cekaman defisit air selama 21-24 hari pada purwoceng berumur tiga bulan menghasilkan kan-dungan stigmasterol dan sitosterol ter-tinggi. Cekaman ringan dengan potensial air pada jaringan daunantara 5-12 bar menghasilkan kandungan bahan aktif steroid dan saponin tertinggi pada tujuh bulan setelah tanam (BST). Perlakuan cekaman defisit air selama 2 bulan dengan pengaturan ketersediaan air tanah setara 60% KL menghasilkan bahan aktif stigmasterol (0,121%), sitos-terol (0,087%) tertinggi pada tanaman purwoceng berumur lima bulan, sedang-kan empat bulan cekamans defisit air dengan 50% KL menghasilkan kandung-an saponin (0,149%) tertinggi pada umur tanaman tujuh bulan.Penyakit mosaik tercatat sebagai salah satu faktor pembatas dalam produksi tanaman nilam ( Pogostemon cablin ). Penelitian ini dilakukan untuk mengukur pengaruh infeksi virus penyebab penyakit mosaik terhadap produksi dan kadar minyak tanaman nilam. Bahan yang digunakan dalam penelitian ini adalah tiga varietas unggul tanaman nilam yaitu Sidikalang, Lhokseumawe dan Tapak Tuan. Infeksi Potyvirus berhasil dideteksi pada varietas Tapak Tuan dan Lhok-seumawe berdasarkan hasil metode ELISA. Pengukuran berat terna basah, terna kering, kadar minyak dan kadar patchouli alcohol (PA) yang dilakukan pada tanaman berumur enam bulan menunjukkan terjadinya penurunan produksi dan kadar minyak. Penurunan tertinggi berat terna basah, terna kering, kadar minyak dan kadar PA berturut-turut dapat mencapai 34,65, 40,42, 9,09 dan 5,06%.Pengaruh pemupukan terhadap intensitas serangan penyakit budok, dan pertum-buhan tanaman nilam telah dilakukan di daerah endemik penyakit budok di Nagari Situak Pasaman Barat sejak Juli 2009 sampai Maret 2010. Perlakuan disusun dalam Rancangan Acak Kelompok 8 perlakuan dan 4 ulangan. Perlakuan yang diuji adalah pupuk NPK (PL) 250 kg/ha, pupuk kandang (Po) 20 t/ha, kompos nilam (Kn) 10 t/ha, kombinasi (PL + Po), (PL + Kn), (Po + Kn,) (PL + Po + Kn) dan kontrol (tanpa pupuk). Hasil pene-litian menunjukkan bahwa semua perla-kuan memberikan pengaruh positif dalam menekan serangan penyakit budok, pem-berian pupuk NPK 250 kg/ha + pupuk kandang 20 t/ha + kompos nilam 10 t/ha mampu menekan intensitas serangan budok sekitar 48,49% dan menghasilkan pertumbuhan tanaman lebih baik dibanding perlakuan lain dengan rataan tinggi tanaman 96,83 cm, jumlah cabang primer 27,50 buah, diameter tajuk 104,98 cm dan produksi terna 1187,50 g/rumpun, hasil ini tidak berbeda nyata dengan pemberian pupuk kandang 20 t/ha + pupuk NPK 250 kg/ha dan pemberian pupuk kandang 20 t/ha + kompos 10 t/ha, tapi berbeda nyata dengan perlakuan kontrol dengan rataan tinggi tanaman 69,58 cm, jumlah cabang primer 19,50 buah, diameter tajuk 65,27 cm dan produksi terna 552 g/rumpun.

Evaluation of Plant Growth Promoting Rhizobacteria as a Protecting Agent Against Cucumber Mosaic Virus and Chilli Veinal Mottle Virus on Chillipepper

A number of abiotic stress responsive genes have been identified from various plant species through reverse genetic strategy. A group of genes are involved in plant responses to stress; they are activated by diverse stress conditions and through different mechanisms. One single gene can be induced by several different stress factors; on the other hand, a number of genes can be up-regulated by a single factor. In Physcomitrella patens, through Northern hybridization, the transcript level of the gene GFDD4-I was detected to be markedly increased by ABA, dehydration and cold, but not by salinity and osmotic stress. In Arabidopsis thaliana, a homologous gene to GFDD4-1 namely At2g47770, was confirmed to fulfill similar function as in P. patens: it is inducible by various abiotic stress treatments, i.e. ABA, dehydration, salinity, and cold. Inducible genes in response to abiotic stress factors may be responsible for plant tolerance to those factors.