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Oil palm (Elaeis guinnensis Jacq) is one of the highest yielding plants in oil producing crops and the most important plantation and commercial crop in Indonesia. However, some fungal diseases have reduced the annual production of oil palm in South East Asia (Idris et al. 2003). Fungal pathogen Ganoderma boninense, the causal agents of basal stem rot (BSR) in oil palm, can severely attack the plant leading toThe effects of mycorrhizal endosymbiotic bacteria Bacillus subtilis B10 and composite of arbuscular mycorrhizal fungal spores in green house experiment were examined in order to evaluate their effectiveness and compatibility with oil palm seedlings in the presence of a fungal pathogen Ganoderma boninense, the most serious pathogen in oil palm (Elaeis guineensis Jacq) in Indonesia. A three factors experiment were conducted, with mycorrhizal inoculation (M0 and M1), bacterial B. subtilis B10 inoculation (B0 and B1), and G. boninense inoculation (G0 and G1) as the first, second, and third factors, respectively. The results showed that disease severity index, plant height, root dry-weight, and phosphorus uptake were affected by co-inoculation of mycorrhizal endosymbiotic bacteria B. subtilis B10 and composite of arbuscular mycorrhizal fungi. Coinoculation of mycorrhizal endosymbiotic bacteria B. subtilis B10 and arbuscular mycorrhizal fungi did not only reduce the percentage of basal stem rot incidence, but also significantly increased plant height and phosphorus uptake by oil palm seedlings. Our results suggest that in oil palm seedlings mycorrhizal endosymbiotic bacteria B. subtilis B10 worked synergistically with arbuscular mycorrhizal fungi in increasing plant adaptation toward biotic stress of pathogen G. boninese and could be promising biocontrol agents.Key words: arbuscular mycorrhizal fungi, Bacillus subtilis B10, biotic stress, Ganoderma boninense, mycorrhizal endosymbiotic bacteria, oil palm seedlings Patogen Ganoderma boninense Pat penyebab penyakit busuk pangkal batang merupakan patogen paling mematikan pada tanaman kelapa sawit (Elaeis guineensis Jacq). Ko-inokulasi bakteri endosimbiotik mikoriza Bacillus subtilis B10 dan komposit dari spora fungi mikoriza arbuskular pada bibit kelapa sawit telah dievaluasi efektivitas dan kompatibilitasnya dalam meningkatkan daya adaptasi bibit kelapa sawit terhadap cekaman biotik patogen G. boninense Pat. Percobaan tiga faktor dalam rumah kaca telah dilakukan dengan faktor pertama adalah inokulasi fungi mikoriza arbuskular yang terdiri dari tanpa inokulasi (M0) dan dengan inokulasi (M1). Faktor kedua adalah inokulasi bakteri B. subtilis B10 yang terdiri dari tanpa inokulasi (B0) dan dengan inokulasi (B1), sementara faktor ketiga adalah inokulasi patogen G. boninense yang terdiri dari tanpa inokulasi (G0) dan dengan inokulasi (G1). Hasil penelitian menunjukkan bahwa ko-inokulasi bakteri endosimbiotik mikoriza B. subtilis B10 dan komposit spora fungi mikoriza arbuskular mempengaruhi indeks keparahan penyakit, tinggi tanaman, bobot kering akar dan penyerapan fosfor o...

Four isolates (BGi1, BGi2, BGi3, and BGi4) bacteria were isolated from surface sterilized arbuscular mycorrhizal fungi (AMF) spores of Gigaspora margarita (Gm). Based on 16S rDNA analyses and phylogenetic tree, it was revealed that isolates BGi1, BGi3 and BGi4 belong to genus Bacillus, whereas BGi2 was very close to Bacillus megaterium EG 24. Enzymatic activity test showed that all four isolates had cellulase and protease activities; while one isolate (Bacillus sp. BGi4) also has pectinase activity in addition to the celulase and protease activities. Dual inoculation of Melia azedarch Linn roots by B. megaterium BGi2 and AMF spores G. margarita enhanced mycorrhizal root colonization by 58.3 %. Combination of Bacillus sp. BGi1 and G. margarita increased height, diameter, shoot biomass, and root biomass of M. azedarch by 353, 4.8, 4546, and 2810%, respectively, in comparison to the uninoculated control plant