No abstract

Pepper plants showing Begomovirus-like symtoms, consisting of yellowing, leaf curling, and distortion, werecollected from fields located in the Padang, West Sumatra. The aim of this research is to identification ofbegomovirus associated with yellow leaf curl diseases on pepper. Total DNA was extracted from infected leaftissue according to Doyle and Doyle (1999) with slight modification. Polymerase chain reaction (PCR) was used toamplify the coat protein region of the virus using universal degenerate primers pAV494 and pAC1048. The PCRamplified DNA product (approx. 560 bp) was sequenced. The nucleotide and amino acid sequences and BLASTsearch revealed highest homology with pepper yellow leaf curl Indonesia virus isolated pepper, tomato andAgeratum conyzoides from Java, but differences from those of tomato yellow leaf curl virus. The isolate was thententatively called pepper yellow leaf curl Indonesia virus-Padang (PYLCIV-Pdg).

Vascular streak dieback (VSD) symptoms was reported recently in several cacao plantations in West Sumatera.  Disease incidence reached 58.82–100% with disease intensity of 24.29–44.71%.  In some cases, dead plant was also found. Fungal isolation was performed to identify the agents associated with VSD.  Plant samples showing VSD symptoms was collected from 3 locations of cacao production center in West Sumatera, i.e. Limapuluh Kota regency, Padang Pariaman regency, and Padang city.  Small pieces of leaf and twig were plated on water agar and potato dextrose agar medium for fungal isolation.  Morphology of hifa, basidiocarp, and basidiospora observed from fungi colonies indicated the presence of Ceratobasidium theobromae on infected plant samples.  This is the first report on the association of C. theobromae on cacao in West Sumatera.

Daerah rizosfer tanaman merupakan daerah yang kaya mikrob, salah satunya ialah kelompok cendawan. Penelitian ini bertujuan mengisolasi cendawan rizosfer dari tanaman krisan sehat dan menguji potensinya sebagai agens hayati untuk pengendalian Fusarium oxysporum penyebab penyakit layu. Isolasi cendawan rizosfer dilakukan dengan metode pengenceran berseri pada medium agar-agar dekstrosa kentang. Ada 6 isolat cendawan yang diperoleh dari rizosfer. Uji patogenisitas menunjukkan bahwa 6 isolat tersebut bukan patogen karena tidak menimbulkan gejala penyakit layu pada tanaman krisan. Hasil seleksi kemampuan antagonisnya menunjukkan bahwa 4 isolat mempunyai kemampuan daya hambat (46.42-51.61%) dan antibiosis terhadap F. oxysporum. Isolat yang memiliki potensi agens hayati ini diidentifikasi sebagai Trichoderma sp. (2 isolat), Penicillium sp., dan Paecilomyces sp.

ABSTRAKPenyakit daun keriting (kerupuk) merupakan penyakit baru pada tanaman tembakau di Sumatera Barat. Penyakit ini sudah tersebar di seluruh area pertanaman tembakau di Kabupaten Limapuluh Kota dengan intensitas serangan 2.5-26.3%. Hasil amplifikasi dengan metode polymerase chain reaction menggunakan primer universal Begomovirus PAL1v 1978/PAR1c 715 dari daun tanaman tembakau yang bergejala menghasilkan amplikon berukuran 1600 pb. Hasil ini mengindikasikan adanya infeksi Begomovirus. Analisis urutan DNA isolat Sumatera Barat menggunakan program NCBI BLAST, menunjukkan bahwa isolat Begomovirus tersebut memiliki homologi dengan Pepper yellow leaf curl Indonesia Virus yang menginfeksi tanaman tomat sebesar 89% dan tanaman cabai 91-97% di Sumatera Barat. Hasil identifikasi ini merupakan laporan pertama infeksi Begomovirus pada tanaman tembakau di Sumatera Barat. ABSTRACTTobacco leaf curl disease ("kerupuk") is a new disease on tobacco in West Sumatra. This disease has spread throughout the tobacco planting area in District Limapuluh Kota with intensity of 2.5-26.3%. DNA fragment of 1600 bp was successfully amplified using polymerase chain reaction method with primer pairs for Begomovirus PAL1v 1978/PAR1c 715 from tobacco leaves showing symptoms. This result indicated Begomovirus infection. Sequence analysis based on NCBI BLAST program showed that Begomovirus infecting tobacco in West Sumatera has the highest homology of 89% and 91-97% with Pepper yellow leaf curl Indonesia Virus infecting tomato and chili pepper in West Sumatera, respectively. This is considered as the first report of Begomovirus infection on tobacco in West Sumatra.