Endophytic bacteria live in plant host tissues without causing any symptoms. The aim of this study was to examine the indigenous endophytic bacteria on sugarcane plantlets produced from the young leaf cells by using tissue culture techniques. To detect the existence of endophytic bacteria in the plantlet tissue, a series of molecular method based on PCR were applied by using ribosomal intergenic spacer (RIS) primer followed by 16S rDNA partial sequence and single strand conformation polymorphism (SCCP). The results showed that the molecular method could detect the existence of bacteria in the tissues. Using the same methods, the bacteria were also found in other developmental stages of sugarcane (explants, differentiated tissues and callus).

Begomovirus infection was identified from tomato growing areas in West Java (Bogor), Central Java (Boyolali), and D.I. Yogyakarta (Kaliurang). Efforts to reduce the infection among others are planting resistance varieties. This research was undertaken to evaluate 14 tomato genotypes for their response to the infection. Dot blot hybridization using nonradioactive (digoxigenin) DNA probe was employed to determine the presence of begomovirus in inoculated plants. Polymerase chain reaction-amplified product of DNA clone of tobacco leaf curl virus –Indonesia was used as a source of DNA probe. All of tomato genotypes evaluated in this study was infected separately by three strain of begomovirus (GVPSlm, GVABy, GVCBgr). Tomato genotypes Bonanza, Jelita, Safira, Permata, Presto, PSPT 8, PSPT 5B, Apel-Belgia, Karibia, Mitra, PSPT 9, Marta, and PSPT 2, showed susceptible or highly susceptible response to the three strains of begomovirus. Exception to those was shown by cv. Intan which resulted in moderate resistance when inoculated with GVCBgr although it resulted susceptible response with the other two strains. Dot-blot hybridization technique was proved to be a powerful tool to detect begomovirus infection in plants showing symptom as well as symptom-less plants. Accumulation of the virus in those plants was relatively high, except in cv. Bonanza and Apel-Belgia. Dot-blot hybridization technique using DIG-labeled DNA probe was able to detect begomovirus DNA in infected tissue up to 10-2 dilution factor.

Anastatus dasyni Ferr wasp (Hymenoptera: Eupelmidae) is one of the parasitoids attacking eggs of the pepper berry sucking bug, Dasynus piperis China (Hemiptera: Coreidae). Study was conducted in the laboratory to determine immature development, adult longevity, fecundity, sex ratio, oviposition preference, and number of host parasitized. The result showed that immature development time from egg up to adult was 15.57 ± 0.09 days, mean fecundity was 99.45 ± 5.60 eggs, and sex ratio (% of females) was 67.28 ± 0.56%. If provided with honey 10% and host eggs, females lived for 37.7 ± 2.78 days and males 6.30 ± 0.56 days. Host eggs aged one and two days were more preferred by A. dasyni for oviposition. Mean number of hosts parasitized by this wasp aged less than one day was much lower as compared to the older one.

A rapid polymerase chain reaction (PCR)-based procedure was developed for detection of Xanthomonas axonopodis pv. glycines, the causal agent of bacterial pustule disease on soybean. A set of primers was designed from partial sequence of the pathogenicity gene of X. axonopodis pv. glycines strain YR32. Specific PCR product of 490 base pairs was produced from strains of X. axonopodis pv. glycines originally from Indonesia as well as from Taiwan. No other pathovars and bacterial species among those tested showed amplification product under optimized PCR conditions. Shaking infected soybean leaves in phosphate buffer saline during six hours was proved to be an essential in order to increase cell number of the bacterial. The procedure was applicable and reliable for detecting of pathogens in infected plant materials. The procedure was proved to be more effective than that of conventional detection and could be of great help for monitoring of pustule bacterial disease in the soybean fields.

Enteropathogenic Escherichia coli (EPEC) causes gastrointestinal infections in human. EPEC invasion was initiated by attachment and aggressive colonization on intestinal surface. Attachment of EPEC alter the intestine mucosal cells. Despite this, the pathogenic mechanism of EPEC infectior has not been fully understood. This research hypothesizes that extracellular proteolytic enzymes is necessary for EPEC colonization. The enzyme is secreted into gastrointestinal milieu and presumably destroy mucus layer cover the gastrointestinal tract. The objective of this study was to assay EPEC extracellular protease enzyme by using mucin substrate. The activity of EPEC extracellular proteolytic enzyme on 1% mucin substrate was investigated. Non-pathogenic E. coli was used as a negative control. Positive and tentative controls were Yersinia enterocolitica and Salmonella. Ten EPEC strains were assayed, seven of them were able to degrade mucin, and the highest activity was produced by K1.1 strain. Both positive and tentative controls also showed the ability to digest 0.20% mucin.

The objectives of this study were (i) to evaluate responses against F. oxysporum f.sp. cubense (Foc) infection of abaca variants regenerated using four different methods, (ii) to determine initial root length and plant height effects on survival of inoculated abaca variants, and (iii) to identify Foc resistance abaca variants. In the previous experiment, four abaca variant lines were regenerated from (i) embryogenic calli (TC line), (ii) ethyl methyl sulphonate (EMS) treated embryogenic calli (EMS line), (iii) EMS treated embryogenic calli, followed by in vitro selection on Foc culture filtrate (EMS+CF line), and (iv) EMS treated embryogenic calli, followed by in vitro selection on fusaric acid (EMS+FA line). All abaca variants were grown in a glasshouse and inoculated with Banyuwangi isolate of Foc (Foc Bw). Initial root length (RL) and plant height (PH) of the abaca variants were recorded before inoculation, while scores of plant damage (SPD), and their survival were recorded at 60 days after inoculation (DAI). The results showed that the initial RL and PH did not affect survival of the tested abaca variants. Regardless of their initial RL and PH, susceptible abaca variants died before 60 DAI while resistance ones still survived. Abaca variants regenerated from single clump of embryogenic callus showed an array of responses against Foc Bw infection, indicating the existence of a mix cells population. The Foc Bw resistance abaca variants were successfully identified from four tested abaca variant lines, although with different frequencies. However, more Foc Bw resistance abaca plants were identified from EMS+CF line than the others. Using the developed procedures, 8 resistance abaca plants were identified from abaca cv. Tangongon and 12 from abaca cv. Sangihe-1.

Enteropathogenic Escherichia coli (EPEC) causes gastrointestinal infections in human. EPEC invasion was initiated by attachment and aggressive colonization on intestinal surface. Attachment of EPEC alter the intestine mucosal cells. Despite this, the pathogenic mechanism of EPEC infectior has not been fully understood. This research hypothesizes that extracellular proteolytic enzymes is necessary for EPEC colonization. The enzyme is secreted into gastrointestinal milieu and presumably destroy mucus layer cover the gastrointestinal tract. The objective of this study was to assay EPEC extracellular protease enzyme by using mucin substrate. The activity of EPEC extracellular proteolytic enzyme on 1% mucin substrate was investigated. Non-pathogenic E. coli was used as a negative control. Positive and tentative controls were Yersinia enterocolitica and Salmonella. Ten EPEC strains were assayed, seven of them were able to degrade mucin, and the highest activity was produced by K1.1 strain. Both positive and tentative controls also showed the ability to digest 0.20% mucin.

Xylan is the major constituent of hemi cellulose. Several enzymes are needed to hydrolyse xylan completely, including xylanase. Currently, there is an increasing use of this enzyme. This study was carried out to characterize the xylanase from Streptomyces spp. strain C1-3. Results showed that the xylanase displayed its highest activity at pH 3 and 90 oC and was stable up to 10 hours at this conditions. Its activity increased after the addition of Cu2+, Fe2+, and Co2+ under concentration of 1 and 5 mM, respectively. The activity however, decreased after the addition of Mg2+, Ca2+ at 1 mM and Zn2+ at 5 mM. After a test with five kinds of xylan (i.e. from Birchwood, Beechwood, Arabinoxylan, Oat spelt and CMC), the xylanase of Streptomyces spp. C1-3 showed its preferences to Birchwood- and Arabino-xylan. The results showed that the xylanase of Streptomyces spp. C1-3 was characterized as a thermostable acid xylanase.

Endophytic fungi have been reported possess an interesting ability to mimic their host plant metabolites. Several fungi also show their specific capability to biotransform the chemical constituents of the host plant. The endophytic fungus Diaporthe sp. E isolate obtained from young stem of a tea plant (Camellia sinensis) show their unique capability to biotransform (−)-epigallocatechin-3-O-gallate [(−)-EGCG] into a major product in glucose-peptone-yeast extract medium that incubated under dark condition at 27 °C for 48 h. The major biotransformation product were isolated and purified through column chromatography techniques using Sephadex LH-20 and silica gel. The chemical structure of the major product were elucidated as (−)-2R,3S-dihydromyricetin based on their IR, FAB-MS, 1D- and 2D-NMR spectra.

Tobacco Mosaic Tobamovirus (TMV) is one of many important viruses infecting Solanaceous plants including hot pepper in Indonesia. To accomplish and improve the effectiveness of virus management, we used root-colonizing bacteria (rhizobacteria) isolated from healthy hot pepper. Eight rhizobacteria isolates were selected and their capacity in enhancing plant growth and inducing systemic resistance (ISR) against TMV in greenhouse trials were evaluated. The rhizobacteria was applied as seed treatment and soil drench. Bacterized-seedling showed a better growth vigor, fitness and a milder symptom than non-bacterized control plants. The protective effect of rhizobacteria was more pronounced after challenging inoculation by TMV, especially for plants treated by isolates I-6, I-16, and I-35. However, TMV accumulation was slightly affected by bacterial treatment. The rhizobacteria might improved ISR by increasing peroxidase enzyme activity but this depends on the species. Based on whole results, isolate I-35 was the potential plant growth promotion rhizobacteria (PGPR). The I-35 was identified as Bacillus cereus based on morphological characteristics and nucleotide sequences of 16S r-RNA.