Jurnal Fitopatologi Indonesia
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Deteksi dan Evaluasi Keragaman Genetika Candidatus Liberibacter asiaticus sebagai Penyebab Penyakit Huanglongbing di Indonesia Berdasarkan Gen β-operon
Huanglongbing also known in Indonesia as citrus vein phloem degeneration (CVPD) is a devastating disease in citrus plantation worldwide, especially in Asia, Africa, and America. In Asian countries including Indonesia, Candidatus Liberibacter asiaticus (CLas) has been confirmed as the causal agent of huanglongbing disease on citrus. Distribution of CLas in Indonesia has been reported in West Borneo, East Nusa Tenggara, Bali, Yogyakarta, Central Java and East Java. The purpose of this study was to detect CLas in several Indonesia’s citrus plantations that has not and has been reported previously and to study its genetic diversity and their relationship. DNA of plant samples, i.e. citrus leaves, was extracted using CTAB method and CLas was amplified using PCR with the A2/J5 primer pair. DNA amplification results showed that infection of CLas was positively detected from samples from Bogor and Cibodas (West Java), Tuban and Jember (East Java), as well as Katung, Bayung Gede, Kerta, and Pancasari (Bali). Alignment of nucleotide sequences from positive samples showed that their ribosomal protein β-operon has high similiarity to that of CLas OK901 originated from Okinawa (Japan). Isolates of CLas originated from Bogor, Cibodas, Tuban, Jember, and Katung have been known to be identical to other CLas of Indonesian origins reported earlier. Isolates of CLas originated from Bayung Gede, Pancasari, and Kerta have single nucleotide polymorphisms at 6 points of bases of the 539 total bases compared in their conservative regions, although only 3 of the 6 bases could affect their amino acid sequences.
Spesies Meloidogyne Penyebab Puru Akar pada Seledri di Pacet, Cianjur, Jawa Barat
Root knot nematodes (RKN) Meloidogyne spp. is the primary parasite of celery and reported to cause losses up to 70%. Identification of the Meloidogyne species on celery in Indonesia has not been reported. This study was aimed to identify the species of Meloidogyne on celery based on morphology characters. Samples of Meloidogyne-infected celery plants were taken using purposive sampling method from Ciputri Village, District of Pacet, Cianjur, West Java Province. RKN inside root tissue was detected by acid fuchsin staining method. Meloidogyne species identification was done by morphological observation of female perineal pattern. Disease symptoms found in the field include leaf yellowing, stunted, and uneven growth of celery plants. Roots of infected plants showed the formation of small size root knots, in large numbers and forming strands like a chain. Staining NPA in root tissue was successfully detected various stages of nematode development, i.e. eggs, juveniles and female nematodes. Three Meloidogyne species, namely M. incognita, M. arenaria and M. javanica were identified
Identifikasi Patotipe Xanthomonas oryzae pv. oryzae dari Tanaman Padi di Sulawesi Selatan
Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight (BLB), one of important constraint in rice production. The pathogen is known to have many pathotypes which caused difficulties in disease control. This research was conducted to determine the distribution of X. oryzae pv. oryzae’s pathotypes in seven districts in South Sulawesi. Grouping of pathotypes was performed according to Kozaka method, i.e. based on the response of differential rice varieties. Infection of X. oryzae pv. oryzae was confirmed by PCR using specific primers XOR-R2/XOR-F. Out of 36 isolates, 29 isolates were identified as X. oryzae pv. oryzae which belong to pathotype III (6 isolates), pathotype IV (21 isolates), and pathotype XII (2 isolates). This result indicated that X. oryzae pv. oryzae pathotype IV was distributed widely in South Sulawesi
Penekanan Perkembangan Penyakit Bercak Ungu pada Bawang Merah oleh Cendawan Mikoriza Arbuskula
Arbuscular mycorrhizal fungi (AMF) is known to improve the growth of shallot (Allium cepa var. aggregatum) and strengthen the resistance of plants toward disease infection. This research aimed to find out the roles of AMF in suppressing the development of purple blotch disease caused by Alternaria sp. on shallot in Caturtunggal, Sleman, Yogyakarta. Inoculation of AMF either on fertilization of N, P, K or without fertilization treatment resulted on higher plant height and number of leaves compared to those without AMF inoculation. The plant inoculated with AMF had lower purple blotch disease intensity and disease progression than control and fungicide treatment. The result showed that AMF, in addition to act as the bio-fertilizer, is a potential to be a biocontrol agent
Waktu Inkubasi pada Derajat Distilasi Kitosan Enzim dan Efektifitas Penghambatannya terhadap Penyakit Antraknosa
The use of chitosan as a coating agent of harvested fruits is an alternative method in controlling anthracnose disease (Colletotrichum sp.). This study aimed to obtain an optimal enzymatic chitosan (EC) that hydrolyzed using chitinase from Burkholderia cepacia isolate E76. The optimal incubation condition to produce EC was 2 h with the yield of 3.52 ± 0.38 g. The degree of deacetylation (DD) chitosan and EC was 66.91% and 80.91%, respectively. Based on in vitro assays, EC 2% was the most effective in inhibiting the growth of Colletotrichum sp. (94.22%) than chitosan, while the highest inhibition for chitosan 3% was 55.26%. Moreover, the EC 2% showed the highest inhibition of spore germination (74.12%). The in vivo assay revealed that EC 2% showed the highest inhibition on the fungal growth (88.88%), compared to the other concentrations. On the other hand, the EC 2% and 3% gave similar results on inhibition of Colletotrichum sp.of chili (55.55%).
Deteksi Virus Terbawa Umbi Benih pada Bawang Merah Kultivar Biru Bantul
Virus infection on shallots may cause mosaic of leaves and plant dwarf. It is very important to know the identity of the virus as a requirement in determining viral disease management strategy. The research is subjected to identify seed- transmitted viruses from shallot bulbs. Detection of virus from bulb was conducted by growing on test, followed by mechanical inoculation on shallot cultivar Biru Bantul, Chenopodium amaranticolor, and Nicotiana tabacum and morphological observation of virus particle by electron microscope. About 2 weeks after inoculation symptoms was observed, i.e. mosaic and dwarf on shallot cultivar Biru Bantul, local necrotic on C. amaranticolor, but symptomless on N. tabacum. Filamentous particles of 650 nm and 800 nm in length was observed under electron microscope from plants with mosaic and dwarfing symptom, respectively. This indicated the presence of 2 different seed-transmitted viruses on infected shallots. Two species of shallot viruses, i.e. Shallot latent carlavirus (SLV) and Onion yellow dwarf potyvirus (OYDV) was most likely the main seedborne viruses on shallot bulb. Identification based on nucleic acid and protein sequence analysis is necessary for further confirmatio
Mekanisme Pengendalian Penyakit Busuk Batang Jeruk oleh Khamir, Kitosan, Cendawan Mikoriza Arbuskular, dan Bakteri Simbiotiknya
Plant diseases become an important constraint on citrus production. Stem rot disease caused by Botryodiplodia theobromae is a major disease on citrus in Indonesia. This study was aimed to evaluate the mechanism of yeast, arbuscular mychorrhiza fungi (AMF), symbiotic bacteria of AMF and chitosan in controlling stem rot disease. In vitro study was performed to evaluate the mechanism of antibiosis, hyperparasitism, production of volatile compounds, and production of chitinase enzyme. The experiment was continued by in planta assays using yeast, AMF, symbiotic bacteria of AMF, and chitosan either singly or in combination. The experiments were performed using completely randomized design with 3 replications. Disease progress were observed based on its latent period, AUDPC, infection rate, AMF association rate, and total phenol content. In vitro studies indicated that the yeasts showed hyperparasitism to B. theobromae with affinity of 26 cells per hyphae, produced volatile compounds with relative resistance level (RRL) 29.1%, and produced chitinase. Selected symbiotic bacteria from AMF showed antibiosis with RRL 42.9%, production of volatile compounds with RRL 26.7%, and has 98% homology with Bacillus subtilis from Vietnam. Application of yeast + AMF + chitosan delayed disease latent period and suppressed disease incidence. Single AMF and combination of yeast + AMF suppressed disease severity, infection rate, and AUDPC. Application of yeast + AMF showed highest association level of AMF and total phenol content. Therefore, the application of AMF and yeast + AMF is recommended in controlling citrus stem rot disease
Cara Preservasi Fitoplasma dari Jaringan Kacang Tanah Bergejala Sapu untuk Deteksi DNA dengan Teknik PCR
Witches‘ broom of peanut caused by phytoplasma is a common disease found in Indonesia. Phytoplasma is able to be detected using polymerase chain reaction (PCR) technique. One of important factor which determine the successful of phytoplasma amplification is the DNA availability from fresh tissues. The research was aimed to evaluate some preservation methods of phytoplasma from infected plant samples. The aspects to be evaluated consisted of time (1, 2, 3, and 4 weeks), temperature (-20 °C, 4 °C, and 25 °C), and preservation medium (1X PGB buffer, 3 M NaCl, CTAB buffer, 70% ethanol, non medium, and FTA-card) for storing the fresh phytoplasma infected samples. Good preservation method will optimize the phytoplasma DNA amplification using PCR standard technique followed by nested-PCR. The results showed that preservation of samples at -20 °C, 4 °C, and 25 °C in CTAB buffer was able to maintain the tissue freshness for 4 weeks and was able to provide the DNA of either quality or quantity sufficiently for PCR detection. PCR standard using a primer pair P1/P7 showed that not all of the preserved DNA of phytoplasma were amplified positively. However, standard PCR followed by nested-PCR using primer pair fU5/rU3 was able to increase the DNA detectability. Preserved samples derived from various medium and stored for 4 weeks gave positive results. This results were in contrary with previous same samples which were detected negatively by standard PCR technique
Kemampuan Tumbuhan Terna dalam Menekan Potensi Inokulum Rigidoporus microporus
White root disease caused by Rigidoporus microporus is an important disease of rubber tree and is very difficult to control. The ability of some herbaceous plant species to suppress inoculum potential and infection of R. microporus was studied in a pot trial. Nine species of herbaceous plants were examined, i.e. arrowroot (Marantha arundinacea), java curcumin (Curcuma xanthorrhiza), sansevieria (Sansevieria fasciata), Mallaca galangal (Alpinia malaccensis), greater galangal (Alpinia galanga), Indian shot (Canna indica), curcumin (Curcuma longa), wild taro (Colocasia esculenta), and water yam (Dioscorea alata). Pathogen’s inocula as mycelial colonizing rubber wood sticks were buried for 90 days in soil planted with tested plants. The results showed that formation of R. microporus rhizomorph in the soil was lower in pots planted with arrowroot, java cucurmin, sansevieria, Indian shot, and wild taro. All herbaceous plants, except sansevieria, caused suppression of inoculum viability and rhizomorph development. Further observation showed no colonization of rhizomorph nor necrosis of the root was found, except on Mallaca galangal and sansevieria
Ketahanan Kultivar Pisang Lokal Kalimantan Selatan terhadap Penyakit Bercak Sigatoka (Mycosphaerella sp.)
Sigatoka of banana caused by Mycospherella sp. is an important disease, since it causes yield losses. Resistant variety is considered a promising approach for sigatoka disease management. This study was aimed to evaluate the resistance of local banana cultivars from South Kalimantan against sigatoka disease. The fungus was isolated from leaves of Kapas cultivar showing severe symptoms of sigatoka disease, onto potato dextrose agar medium. The isolate was then confirmed as Mycosphaerella sp. following Koch’s postulate. Level of resistance is determined based on symptoms development. Resistance of local banana cultivars can be differentiated into susceptible (‘Awak’, ‘Jaranang’, ‘Kapas’, ‘Mas’, and ‘Paikat’), medium resistant (‘Ambon’, ‘Kepok’, ‘Mas Bantan’, ‘Mauli’, and ‘Talas’), and resistant (‘Tarati’). In general, the symptom was visible 2 to 8 days after inoculation. The longer incubation period the more resistant response of banana varieties. Incubation period was negatively correlated to the disease intensity, but it is not correlated with stomatal density