Aims: To isolate and characterize novel bacteriophages infecting the phytopathogen, Ralstonia solanacearum, and to evaluate them as resources with potential uses in the biocontrol of bacterial wilt. Methods and Results: Fourteen phages infecting R. solanacearum were isolated from soil samples collected in Chiang Mai, Thailand. The phages showed different host ranges when tested against 59 R. solanacearum strains isolated from Thailand and Japan. These phages were characterized as nine podoviruses and five myoviruses based on their morphology. Podovirus J2 in combination with another podovirus (φRSB2) lysed host cells very efficiently in contaminated soil. J2 treatment prevented wilting of tomato plants infected with a highly virulent R. solanacearum strain. Conclusions: Treatment with J2 effectively reduced the amount of the bacterial wilt pathogen in contaminated soil and prevented bacterial wilt of tomato in pot experiments. Myovirus J6 possessed jumbo phage features, giving a unique opportunity to study its utilization as a biocontrol agent. Significance and Impact of the Study: As exemplified by J2, the phages isolated in this study represent valuable resources with potential uses in biocontrol of bacterial wilt. A rare jumbo phage J6 served as a valuable subject to understand and utilize this new group of phages.

This study aims to determine the effectiveness of the STEAM (Science, Technology, Engineering, Arts, and Mathematics)-based biotechnology module equipped with flash animation for learning biology in high school. This research was conducted in a high school, involving 32 students of Year XII. The research design was the design model for development of R2D2 with one group pretestposttest design as effectiveness tests. This study utilized a learning design, biotechnology modules equipped with flash animation, instrument testing, validation sheet and questionnaire as research instruments. Data validation and the questionnaire results were then converted into qualitative data into a category. The effectiveness test data were analyzed using the N gain. The results of the validation material, media and users indicated that the module was valid with the final score of 89.85. Students' responses to the module in terms of readability, clarity of presentation, the attractiveness and usefulness of the results were in very good category (81.2%). The effectiveness test showed that result of post-test greater than pre-test and the value of N gain were in the high category (0.72).

The study aims to develop a valid, practical and effective Biology student's book based on Science Technology Engineering and Mathematics (STEM) on the topic of biotechnology for Grade XII. The method applied for the study was research and development with the 4-D model. The subjects were 58 Grade XII students of SMAN 1 Muncar, Banyuwangi-Indonesia. The results showed that the average of validation result of STEM-based student's book was 86.4% which fell under a strong valid category. The average percentage of legibility test and practicality were in very good category of 87.18% and 96.53%, respectively. Meanwhile, the average of effectiveness test was 0.77 of normalized gain categorized in high criteria. In conclusion, it could be determined that STEM-based student's book of biotechnology is valid, pratical, and effectively used in learning process.

The genome organization, gene structure, and host range of five podoviruses that infect Ralstonia solanacearum, the causative agent of bacterial wilt disease were characterized. The phages fell into two distinctive groups based on the genome position of the RNA polymerase gene (i.e., T7-type and ϕKMV-type). One-step growth experiments revealed that ϕRSB2 (a T7-like phage) lysed host cells more efficiently with a shorter infection cycle (ca. 60 min corresponding to half the doubling time of the host) than ϕKMV-like phages such as ϕRSB1 (with an infection cycle of ca. 180 min). Co-infection experiments with ϕRSB1 and ϕRSB2 showed that ϕRSB2 always predominated in the phage progeny independent of host strains. Most phages had wide host-ranges and the phage particles usually did not attach to the resistant strains; when occasionally some did, the phage genome was injected into the resistant strain's cytoplasm, as revealed by fluorescence microscopy with SYBR Gold-labeled phage particles.

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