Sugarcane mosaic virus (SCMV) is one among many viruses that infect sugarcane, cause yield loss, and become serious disease agents on sugarcane plantations. Since the morphological symptoms of SCMV are similar to other symptoms caused by Sugarcane streak mosaic virus (SCSMV) or nitrogen deficiency, the detection of SCMV is important through accurate diagnostic-like ELISA or RT-PCR. This research aimed to study the causative mosaic pathogen of SCMV in East Java, Indonesia, including mosaic development. The results showed that the mosaic symptom is present in all sugarcane plantations with 78% and 65% disease incidence and severity, respectively. Moreover, the detection procedure based on an amplification of cDNA of the coat protein gene sequence confirmed that SCMV was the causative agent of mosaic disease on sugarcane. Re-inoculation of healthy sugarcane plants with plant sap from a symptomatic leaf from the field showed similar mosaic or yellowish chlorotic areas on the leaf blade, and appeared on the fourth leaves upward from the inoculation leaf, in addition to showing different levels of peroxidase but not total phenol. Mosaic also correlated with the amount of total chlorophyll. Although Sucrose phosphate synthase (SPS) protein accumulation and activity were at a lower level in infected leaves, sucrose accumulation was at a higher level in the same leaves.

Bacterial wilt disease on banana is an important disease in Lumajang District and causes severe yield loss. Utilizing bacteriophage as natural enemy of pathogenic bacteria has been widely known as one of the control strategies. This research was aimed at determining the causing agent of bacterial wilt on banana isolated from Lumajang area, to obtain wide-host range bacteriophages against bacterial wilt pathogen and to know the basic characteristic of bacteriophages, particularly its nucleic acid type. Causative agent of bacterial wilt was isolated from symptomatic banana trees from seven districts in Lumajang area on determinative CPG plates followed by rapid detection by PCR technique using specific pair-primer. Bacteriophages were also isolated from soil of infected banana crop in Sukodono District. Morphological observation showed that all bacterial isolates have similar characteristic as common bacterial wilt pathogen,Ralstonia solanacearum. In addition, detection of FliC region in all isolates confirmed that all isolates wereR. solanacearumaccording to the presence of 400 bp of FliC DNA fragment. Moreover, two bacteriophages were obtained from this experiment (ϕRSSKD1 andϕRSSKD2), which were able to infect all nineR. solanacearumisolates. Nucleic acid analysis showed that the nucleic acid of bacteriophages was DNA (deoxyribonucleic acid).

Bacterial blight disease caused by Pseudomonas syringae pv. glycinea becomes one among several important factors that affects soybean production. To control this pathogen, most farmers apply synthetic pesticides that have negative effect for human, animal, and environment. Therefore, an alternative control must be developed including the use of bacteriophages. Moreover, identification and detection of this pathogen should be accurate for optimal diseases management. On the other hand, bacteriophage, a virus that infects specific host-bacterium, is largely known to have the ability to kill their specific host- bacterium. In addition, bacteriophage is also used as diagnostic tool for bacterial detection and identification of purpose, known as phatovar classification. This research was aimed to isolate the bacterial blight pathogen and their bacteriophage from soybean field in Jember, determine the pathogen pathogenicity and virulence, and determine the host-range of bacteriophage that infects several isolates of bacterial blight pathogen on soybean. The results has shown that among 12 isolates of bacterial blight pathogens that had similar characteristic to P. syringae pv. glycinea, only 10 isolates showed positive hypersensitive response (HR) on tobacco leaf. However, all isolates were virulent when inoculated to soybean leaves by showing particular bacterial blight symptom. In addition, one bacteriophage was found to infect isolate H3, called ϕPSGH3, and was to have 6 hosts among 12 bacterial isolates including isolates H3, SK4-2, BT4-1, KR1-1, KR4-2 dan MG4-1. The results from plaque assay PSGH3 with ϕH3-1 found out three only particle bacteriophage which are ϕGH1, ϕGH2 and ϕGH3

Sugarcane mosaic virus (SCMV) is a mosaic disease that has spread over sugarcane plantations in Indonesia. The important step to overcome the disease is to detect the pathogen as early as possible. Detection of the pathogen can be achieved using the immunodiagnostic method by employing a specific antibody against the viral coat protein. The objective of this research was to produce a polyclonal antibody using the recombinant coat protein of SCMV, and to test its sensitivity for detection of SCMV in the symptomatic plant. The gene encoding of the coat protein was cloned using the RT-PCR Kit and total RNA isolated from symptomatic sugarcane leaves cultivar PS-881. Nucleotide sequences analysis of the cloned cDNA indicated that the cDNA contained 998 nucleotides and named SCMVCp-cDNA. The cDNA was then inserted into a His-tag expression plasmid of pET28a and overexpressed in Escherichia coli BL21 (DE3) to produce a recombinant protein. The recombinant fused protein SCMVCp was strongly expressed in an insoluble fraction, with a molecular size of around 44 kDa, without the addition of an IPTG inducer. Purification of the recombinant protein using an affinity Ni-NTA resin, followed by SDS-PAGE separation, resulted in a high purity of the protein and used as an antigen to raise the polyclonal antibody in a rabbit. The sensitivity of the antiserum determined by western blot analysis showed that the antiserum was able to detect the recombinant protein at a concentration of 10 ng. The western blot analysis also detected a clear single band of 36.7 kDa of the SCMV coat protein in symptomatic sugarcane leaves and not in healthy leaves. Interestingly, when the sample proteins were prepared using low-speed centrifugation, the corresponding coat protein was detected in a soluble fraction by western blot analysis. Thus, the antiserum was successfully used for indirect-ELISA analysis using the soluble protein fraction. The results provide an easy method to detect and diagnose SCMV infection using the immunodiagnostic.