Publications

4435

Huanglongbing also known in Indonesia as citrus vein phloem degeneration (CVPD) is a devastating disease in citrus plantation worldwide, especially in Asia, Africa, and America. In Asian countries including Indonesia, Candidatus Liberibacter asiaticus (CLas) has been confirmed as the causal agent of huanglongbing disease on citrus. Distribution of CLas in Indonesia has been reported in West Borneo, East Nusa Tenggara, Bali, Yogyakarta, Central Java and East Java.  The purpose of this study was to detect CLas in several Indonesia’s citrus plantations that has not and has been reported previously and to study its genetic diversity and their relationship. DNA of plant samples, i.e. citrus leaves, was extracted using CTAB method and CLas was amplified using PCR with the A2/J5 primer pair. DNA amplification results showed that infection of CLas was positively detected from samples from Bogor and Cibodas (West Java), Tuban and Jember (East Java), as well as Katung, Bayung Gede, Kerta, and Pancasari (Bali). Alignment of nucleotide sequences from positive samples showed that their ribosomal protein β-operon has high similiarity to that of CLas OK901 originated from Okinawa (Japan). Isolates of CLas originated from Bogor, Cibodas, Tuban, Jember, and Katung have been known to be identical to other CLas of Indonesian origins reported earlier.  Isolates of CLas originated from Bayung Gede, Pancasari, and Kerta have single nucleotide polymorphisms at 6 points of bases of the 539 total bases compared in their conservative regions, although only 3 of the 6 bases could affect their amino acid sequences. 

AbstractThe olive fruit fly,Bactrocera oleae, is the most destructive pest of olive orchards worldwide. The monophagous larva has the unique capability of feeding on olive mesocarp, coping with high levels of phenolic compounds and utilizing non-hydrolyzed proteins present, particularly in the unripe, green olives. On the molecular level, the interaction betweenB. oleaeand olives has not been investigated as yet. Nevertheless, it has been associated with the gut obligate symbiotic bacteriumCandidatus Erwinia dacicola. Here, we used aB.oleaemicroarray to analyze the gene expression of larvae during their development in artificial diet, unripe (green) and ripe (black) olives. The expression profiles ofCa. E. dacicolawere analyzed in parallel, using the Illumina platform. Several genes were found overexpressed in the olive fly larvae when feeding in green olives. Among these, a number of genes encoding detoxification and digestive enzymes, indicating a potential association with the ability ofB. oleaeto cope with green olives. In addition, a number of biological processes seem to be activated inCa. E. dacicoladuring the development of larvae in olives, with the most notable being the activation of amino-acid metabolism.

Summary As in many deep underground environments, the microbial communities in subsurface high‐CO 2 ecosystems remain relatively unexplored. Recent investigations based on single‐gene assays revealed a remarkable variety of organisms from little studied phyla in Crystal Geyser (Utah, USA), a site where deeply sourced CO 2 ‐saturated fluids are erupted at the surface. To provide genomic resolution of the metabolisms of these organisms, we used a novel metagenomic approach to recover 227 high‐quality genomes from 150 microbial species affiliated with 46 different phylum‐level lineages. Bacteria from two novel phylum‐level lineages have the capacity for CO 2 fixation. Analyses of carbon fixation pathways in all studied organisms revealed that the Wood‐Ljungdahl pathway and the Calvin‐Benson‐Bassham Cycle occurred with the highest frequency, whereas the reverse TCA cycle was little used. We infer that this, and selection for form II RuBisCOs, are adaptions to high CO 2 ‐concentrations. However, many autotrophs can also grow mixotrophically, a strategy that confers metabolic versatility. The assignment of 156 hydrogenases to 90 different organisms suggests that H 2 is an important inter‐species energy currency even under gaseous CO 2 ‐saturation. Overall, metabolic analyses at the organism level provided insight into the biochemical cycles that support subsurface life under the extreme condition of CO 2 saturation.