Aris Tjahjoleksono

Characterization and Identification of Phosphate Solubilizing Bacteria Isolate GPC3.7 from Limestone Mining Region

Phosphate (P) are one of major macronutrients needed by plants. P in the soil are present in the organic and inorganic form. The amounts of P in marginal soil can be increased with plant growth promoting rhizobacteria (PGPR). The aim of this study was to characterize and identify P solubilizing bacteria (PSB) isolate GPC3.7 that characteristically could fix N from the soil around limestone mining area. There were 44 PSB isolates found from 15 soil samples around limestone mining area, Blindis mountain, Cirebon. The solubility index of all strain were measured about 0.125 to 2.375 on Pikovskaya media. There were 22 PSB isolates were grown on N-free bromothymol blue (NfB) medium and 19 isolates were grown on Congo Red Agar (CRA) medium. Only 10 isolates were indicated as symbiotic living microorganisms whereas 12 others were categorized as N-free fixing bacteria. Isolate GPC3.7 was chosen to be further observed, based on its P solubility index, N-fixing ability and growth stability. Phosphate quantitative estimation assay of isolate GPC3.7 was unmeasured. The P soluble concentration of GPC3.7 might be lower than 1 mg/L. The colony of GPC3.7 morphologically had round shape, entire margin, raised elevation and white color. Isolate GPC3.7 was Gram negative bacteria with coccus cell shape. Based on 16S rRNA gene, GPC3.7 was closely relative to Acinetobacter baumannii.

Pertumbuhan Planlet Lidah Mertua (Sansevieria sp.) Blue Leaf dari Kultur Kalus

Lidah mertua ( Sansevieria sp.) Blue Leaf is a slow growing ornamental plant. It is also difficult to reproduce. Therefore market demands for this plant is impossible to fulfill through conventional methods of propagation such as leaf cutting or layering. Tissue culture is one of the alternatives to solve the problem of plant propagation. In vitro culture of Sansevieria calli was induced for shooting, and rooting afterwards. The basic media of WP was superior than MS in producing multiple shoots, and this WP media containing of BAP 5 mg/L and NAA 0,5 mg/L (WH1) gave the highest number of shoots and leaves on plantlets, as well as the best growth performance. The shoots started to appear two weeks after culture. Plantlets from WH1 rooted in higher frequency as well on rooting media. A mixture of compost, sand, and zeolit (4:4:1) enriched with a nutritive solution, composting of 1⁄4 WP plus IBA 0.5 mg/L, was a poreous media that was able to induce rooting of this plant.

Horizontal Gene Transfer and Population of Phyllosphere Bacteria on Transgenic and Nontransgenic Cotton

The possibility of horizontal gene transfer of plant genomic DNA and bacteria in the soil, particularly as this relates to the possible transfer of genes encoding antibiotic resistance, has been seen as hazard associated with genetically engineered plants. It is hypothesized that introduction of bacterial genes into the plant genome leads to a higher probability of gene transfer from plants to bacteria due to the presence of homologous sequences. Bollgard (BG) cotton was constructed through the introduction of cry1A(c) gene, encodes for insecticidal activity againts Lepidopteran pests, together with genes for spectinomycin/streptomycin resistant (aad) and kanamycin resistant (nptII), into the genome of a conventional cotton variety, Delta Pine (DP). The aim of this study were to evaluate the ability of naturally competent Acinetobacter calcoaceticus strain ADP1 to take up and integrate transgenic plant DNA based on homologous recombination under optimized laboratory condition, and to compare phyllosphere microbial population resistant to antibiotic on leaves of transgenic and nontransgenic plant. The results showed that transformation of ADP1 cells with Bollgard DNA was not detected on nitrocellulose membrane nor in sterile soil. Total phyllosphere bacterial population on leaves collected from one month after planting were 1.3 x 108 and 1.6 x 108 cfu/g leave fresh weight for BG and DP, respectively. Samples collected after three month contained 5.9 x 107 and 7.1 x 107 cfu/g leave fresh weight for BG and DP, respectively. This study also showed that there was no significant difference of phyllosphere bacterial population resistant to streptomycin and kanamycin on leaves of BG or DP samples collected from one or three month after planting.Diploid species of peanut (Arachis cardenasii) showed no symptoms of PStV infection when mechanically inoculated with PStV. Some introgression lines derived from A. cardenasii and A. hypogaea hybridization have been introduced to Indonesia. Evaluation of their adaptability and yield potential were necessary before pursuing further utilization of these introgression lines. The objectives of this research were to determine yield potential of the introgression lines of peanut in green house and field conditions and to evaluate incidence of PStV infection in the field. Peanut plants were grown in the green house and in the field according to standard procedures for raising peanut. Results of the experiments showed that growth and developmental characters of the tested lines were similar between field and green house grown plants. The introgression lines generally exhibited higher secondary branches and longer to flower and harvest as compared to peanut cv. Gajah and Kelinci. The NC-CS30 line was identfied as having higher yield and bigger seed size as compared to standard peanut cultivars (Gajah and Kelinci). Therefore, NC-CS30 germplasm may be further developed as commercial peanut cultivar or be used as donor for peanut breeding in Indonesia.

Transfer Gen Horizontal dan Populasi Bakteri Filosfer pada Kapas Transgenik dan Nontransgenik

The possibility of horizontal gene transfer of plant genomic DNA and bacteria in the soil, particularly as this relates to the possible transfer of genes encoding antibiotic resistance, has been seen as hazard associated with genetically engineered plants. It is hypothesized that introduction of bacterial genes into the plant genome leads to a higher probability of gene transfer from plants to bacteria due to the presence of homologous sequences. Bollgard (BG) cotton was constructed through the introduction of cry1A(c) gene, encodes for insecticidal activity againts Lepidopteran pests, together with genes for spectinomycin/streptomycin resistant ( aad ) and kanamycin resistant ( npt II), into the genome of a conventional cotton variety, Delta Pine (DP). The aim of this study were to evaluate the ability of naturally competent Acinetobacter calcoaceticus strain ADP1 to take up and integrate transgenic plant DNA based on homologous recombination under optimized laboratory condition, and to compare phyllosphere microbial population resistant to antibiotic on leaves of transgenic and nontransgenic plant. The results showed that transformation of ADP1 cells with Bollgard DNA was not detected on nitrocellulose membrane nor in sterile soil. Total phyllosphere bacterial population on leaves collected from one month after planting were 1.3 × 10 8 and 1.6 × 10 8 cfu/g leave fresh weight for BG and DP, respectively. Samples collected after three month contained 5.9 × 10 7 and 7.1 × 10 7 cfu/g leave fresh weight for BG and DP, respectively. This study also showed that there was no significant difference of phyllosphere bacterial population resistant to streptomycin and kanamycin on leaves of BG or DP samples collected from one or three month after planting.