Fourteen strains of cucumber mosaic virus (CMV) from Australia have been characterized by their host range and symptomatology. They were classified as subgroup I or II strains by a dot‐blot molecular hybridization assay between their total viral RNAs and selected cDNAs. The strains FNY and LNy, both from the USA, were used as the subgroup I‐ and subgroup II‐type strains, respectively. A range of serological tests was used to compare these isolates. Gel immunodiffusion tests, with standard antigens homologous to the antisera prepared against glutaraldehyde‐fixed virus of 11 strains, showed that they could be divided into three serogroups on the basis of spur formation in heterologous reactions. Two of the serogroups included either subgroup I or subgroup II isolates, whereas the third serogroup consisted of only one strain (YWA) which was homologous to all the strains tested. Use of heterologous standard antigens in this test failed to show further subgrouping of the antigens. Double‐antibody sandwich (DAS) ELISA using polyclonal antibodies to distinct virus strains also placed the 14 strains in the same three serogroups. When eight different monoclonal antibodies (MAbs) were used in indirect ELISA, one of them distinguished subgroup‐I strains and another distinguished subgroup‐II strains; the YWA strain fell into subgroup II. Other MAbs showed narrower or broader specificity. Thus both molecular hybridization with total RNA and specific MAbs may be useful for separating isolates of CMV into subgroups I and II. Spur formation using heterologous standard antigens to the antisera, as well as being more difficult to interpret, was not a reliable criterion for classification.
The symptoms and host ranges of 16 strains of cucumber mosaic virus (CMV) from both Subgroup I and II were compared on selected pasture and grain legumes. None infected either Arachis hypogea or Glycine max, although 13 other plant species were infected. The observation that success of inoculation varied with the time of year, may limit the usefulness of the biological differentiation of strains. No hosts tested distinguished Subgroup I or II isolates. The distribution of symptoms and virus in Medicago spp. was uneven and the virus was first detected in some cultivars 6-12 weeks after inoculation, indicating that any test for resistance to CMV in these species would have to be prolonged. Most cultivars of lupin tested were severely affected by several strains of CMV, which caused necrosis and death under conditions which excluded other pathogens.
Abstract. Nurcahyanti SD, Wahyuni WS, Masnilah R, Nurdika AAH. 2021. Diversity of Bacillus spp. from soybean phyllosphere as potential antagonist agents for Xanthomonas axonopodis pv. glycines causal of pustule disease. Biodiversitas 22: 5003-5011. Pustule disease caused by Xanthomonas axonopodis pv. glycines (Xag) is an important disease in soybean. Bacteria from soybean phyllosphere is one of the potential biological agents against this disease. This is because the microorganisms have similarity. This study aimed to determine the diversity and species of bacteria from the soybean phyllosphere that have potential as biological agents. The research was carried out by morphological observation, physiological - biochemical testing, and molecularly with BOX AIR primer. Molecular identification was carried out by amplifying the 16S-rRNA gene with 27F and 1492R primers. The results showed that 11 isolates could inhibit Xag in vitro which showed morphological, biochemical, and molecular diversity. These bacteria were identified as Bacillus spp. which consisted of 4 groups, namely Bacillus siamensis, B. subtilis. B. amyloliquifaction and B. velezensis. The diversity of phyllosphere bacteria allows them to be used as biological agents because they do not inhibit each other and have diverse living abilities in various environmental conditions.
Jember merupakan salah satu Kabupaten penghasil padi terbesar di jawa timur, Indonesia. Sayangnya berdasarkan Badan Pusat Data Statistik (BPS) pada tahun 2015-2016, produksi padi di Kabupaten Jember Menurun hingga 20.000 ton per tahun. Masalah hama dan penyakit menjadi penyebab utama turunnya produktifitas padi di Jember. Di ketahui tanaman padi di Jember dapat diserang oleh beberapa penyakit dalam kurun waktu yang sama dengan insidensi dan keparahan yang berbeda. Penelitian dilakukan guna mengetahui tingkat insidensi dan keparahan penyakit penting di beberapa kecamatan di Kabupaten Jember. Lokasi pengambilan data diperoleh berdasarkan metode pengacakan bertingkat dan dilakukan di musim kering. Sampel diambil dari empat desa per kecamatannya dan per desa diambil minimal empat titik lahan. Hasil menunjukkan Beberapa penyakit diketahui menyerang semua lokasi penyakit seperti Penyakit hawar bakteri (Kresek) dan Blast. Umumnya masing-masing kecamatan berbeda jenis penyakit yang menyerang. Sebagai contoh Tungro dan penyakit lain yang diebabkan oleh virus hanya menyerang pada beberapa lokasi dengan insidensi dan keparahan yang kecil. Data hasil penelitian ini dapat digunakan untuk dasar peramalan terjadinya epidemi penyakit di kemudian hari dan mempersiapkan metode pengendalian penyakit tanaman padi yang bijaksana pada musim yang sama.
Penyakit hawar daun bakteri (HDB) yang disebabkan oleh Xanthomonas oryzae pv. oryzae merupakan penyakit penting di Indonesia. Padi varietas Inpari 30, Situbagendit, Luk-ulo, dan Cibogo diketahui memiliki ketahanan terhadap penyakit HDB sehingga dapat digunakan untuk mengukur ketahanan galur padi baru. Penelitian dilakukan untuk mengevaluasi ketahanan lapangan galur padi baru, yaitu galur X yang memiliki ketahanan terhadap HDB. Penelitian dilakukan di Desa Wirolegi, Kecamatan Sumbersari, Kabupaten Jember dengan infeksi X. oryzae yang terjadi secara alami. Ketahanan tanaman diukur dengan nilai insidensi penyakit (IP) dan keparahan penyakit (KP). IP tertinggi (100%) dicapai oleh semua varietas dan galur uji pada umur yang berbeda. Pada 90 hari setelah tanam, KP pada galur X mencapai 11.85%, jauh lebih rendah dibandingkan dengan KP pada var. Situbagendit (40.25%). Berdasarkan nilai KP dan IP, galur X memiliki ketahanan yang terbaik, yaitu tahan pada fase vegetatif dan agak tahan pada fase generatif. Namun, pada penelitian ini tidak diketahui galur X. oryzae yang menyerang varietas dan galur padi tersebut. Kata kunci: galur padi, insidensi penyakit, keparahan penyakit, Xanthomonas oryzae pv.oryzae
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