ABSTRAKTanaman mentimun dengan gejala daun menguning mulai banyak ditemukan pada sejumlah pertanaman mentimun di Desa Apuan dan Desa Bangli, Provinsi Bali. Penyakit ini diduga berasosiasi dengan Begomovirus karena gejalanya mirip dengan infeksi Begomovirus yang dilaporkan terjadi pada tanaman mentimun di Jawa. Selain itu, kutukebul (Bemisa tabaci) ditemukan di lapangan. Penelitian ini bertujuan mengidentifikasi penyebab penyakit daun kuning pada tanaman mentimun. Deteksi dan identifikasi virus dilakukan dengan teknik polymerase chain reaction menggunakan pasangan primer universal Begomovirus, SPG1/SPG2. Pita DNA berukuran 912 pb berhasil diamplifikasi dari sampel tanaman. Analisis hasil sikuensing nukleotida menunjukkan bahwa Begomovirus yang menginfeksi tanaman mentimun di Bali mempunyai nilai kemiripan tertinggi (91%) dengan Squash leaf curl China virus (SLCCNV) isolat Malaysia. Penelitian ini merupakan laporan pertama infeksi SLCCNV di Bali. ABSTRACTLeaf yellowing symptoms was commonly found in cucumber plants in Bali provinces, i.e. in Apuan and Bangli villages recently. Begomovirus infection is suspected as the causal agent, due to similar symptoms previously reported from cucumber plants in Java. In addition, Bemisia tabaci was observed in the field. The objective of this research was to identify the causal agent of leaf yellowing disease of cucumber in Bali. Virus detection and identification was conducted by polymerase chain reaction method using universal primers for Begomovirus, i.e. SPG1/SPG2. DNA fragment of 912 bp in size was successfully amplified from leaf samples. Analysis of nucleotide sequencing indicated that Begomovirus infecting cucumber plants in Bali has the highest homology (91%) with Squash leaf curl China virus (SLCCNV) isolate from Malaysia. This is the first report of SLCCNV infection in Bali.

The kelulut bee (Meliponini) is a subfamily of stingless bees that produce honey. A total of 89 species out of a total of 500 species of kelulut bees are known to originate from the Indo-Australian region. Kelulut bees do not have quality standards so they still refer to the Codex and EU Directive which basically only applied for Apis honey. The Codex and EU Directive are formed by several psychochemical parameters, one of it is diastase activity. Diastase activity in kelulut honey is known not to meet existing standards or even undetectable. Therefore, this study aimed to explore proteins inside kelulut honey and investigate the possibility of using a specific protein as a biomarker to differentiate honey produced by kelulut bee from other honey. This research can also be considered as an initial step to optimize the exploration of protein in kelulut honey. This research is divided into two sections which are the preliminary research and the research expansion. From preliminary section, glucose dehydrogenase enzyme (GDH) was found to be present inside Tetragonula spp honey. A further examination of GDH enzyme was made in four kelulut bee honeys namely Tetragonula leaviceps, T. biroi, Heterotrigona itama, and Geniotrigona thoracica. The preliminary research has five stages that are exactly the as expansion research section except it didn't include GDH activity measurement. The research includes seven main stages. First honeys were dialyzed to remove the sugar content followed by centrifugation. The samples were then purified using liquid chromatography with anion exchanger column. The molecular weight of proteins was analysed by SDS-PAGE method. The GDH activity was measured using spectrophotometer followed by qualitative analysis using LC-MS/MS. The peptide sequences resulted from LC-MS/MS were then matched with Uniprot to identify the unknow protein. The results showed that only T. biroi and T. laeviceps had GDH enzyme activity of 0,1891 U/mL and 0,1652–1,579 U/mL, respectively. Bands from both species were also qualitatively identified as GDH. With these results, it can be concluded that the GDH enzyme cannot be used as a biomarker to distinguish the kelulut honey.

Yellow disease on Cucurbitaceae caused by Squash leaf curl China virus (SLCCNV; Begomovirus) is an important disease in many countries. Typical yellow leaf curl symptoms was found on cucumber in Tabanan, Bali. The objective of this research is to clone Transcriptional Activator Protein (TrAp) and Replication-Associated Protein (Rep) of SLCCNV Indonesian isolate. Universal primer for Begomovirus, i.e. SPG1/SPG2 was used to amplify DNA fragment of Begomovirus which cover the TrAp and Rep gene. The amplicon of ± 912 bp in size was then cloned into pTZ57R/T plasmid vector by TA-cloning method to obtain plasmid recombinant pTZ-SLCCNV. The plasmid recombinant was successfully confirmed by PCR colony and DNA sequencing. The nucleotide sequences analysis of plasmid recombinant showed highest homology (98%) of the corresponding gene to pumpkin isolate of SLCCNV from Malaysia.

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