The decline ofAcacia mangiumWilld. in Malaysia, especially in Sabah since 2010, is primarily due to Ceratocystiswilt and canker disease (CWCD) caused by theCeratocystis fimbriataEllis & Halst. complex. This study was aimed to investigate the mitochondrial genome architecture of two differentC. fimbriatacomplex isolates from Malaysia: one fromA. mangiumin Pahang (FRIM1162) and another fromEucalyptus pellitain Sarawak (FRIM1441). This research employed Next-Generation Sequencing (NGS) to contrast genomes from diverse hosts with nine additional mitochondrial sequences, identifying significant genetic diversity and mutational hotspots in the mitochondrial genome alignment. The mitochondrial genome-based phylogenetic analysis revealed a significant genetic relationship between the studied isolates and theC. fimbriatacomplex in the South American Subclade, indicating that theC. fimbriatacomplex discovered in Malaysia isC. manginecans. The comparative mitochondrial genome demonstrates the adaptability of the complex due to mobile genetic components and genomic rearrangements in the studiedfungal isolates. This research enhances our knowledge of the genetic diversity and evolutionary patterns within theC. fimbriatacomplex, aiding in a deeper understanding of fungal disease development and host adaption processes. The acquired insights are crucial for creating specific management strategies for CWCD, improving the overall understanding of fungal disease evolution and control.
Metarhizium anisopliae (Metchnikoff) Sorokin, a pathogenic fungus to insects, infects the subterranean termite, Coptotermes curvignathus Holmgren, a devastating pest of plantation trees in the tropics. Electron microscopy and proteomics were used to investigate the infection and developmental process of M. anisopliae in C. curvignathus. Fungal infection was initiated by germ tube penetration through the host's cuticle as observed at 6 h post-inoculation (PI), after which it elongated into the host's integumental tissue. The colonization process continued as seen from dissemination of blastospores in the hemocoel at 96 h PI. At this time point, the emergent mycelia had mummified the host and forty-eight hours later, new conidia were dispersed on the termites' body surface. Meanwhile, hyphal bodies were observed in abundance in the intercellular space in the host's body. The proteomes of the pathogen and host were isolated separately using inoculated termite samples withdrawn at each PI-time point and analyzed in two-dimensional electrophoresis (2-DE) gels. Proteins expressed in termites showed evidence of being related to cell regulation and the immune response, while those expressed in M. anisopliae, to transportation and fungal virulence. This study provides new information on the interaction between termites and its entomopathogen, with potential utilization for developing future biopesticide to control the termite population.
To expand the genomic information of Hypericaceae, particularly on Cratoxylum, we characterized seven novel complete plastid genomes (plastomes) of five Cratoxylum and two of its allied taxa, including C. arborescens, C. formosum subsp. formosum, C. formosum subsp. pruniflorum, C. maingayi, C. sumatranum, Hypericum hookerianum, and Triadenum breviflorum. For Cratoxylum, the plastomes ranged from 156,962 to 157,792 bp in length. Genomic structure and gene contents were observed in the five plastomes, and were comprised of 128-129 genes, which includes 83-84 protein-coding (CDS), 37 tRNA, and eight rRNA genes. The plastomes of H. hookerianum and T. breviflorum were 138,260 bp and 167,693 bp, respectively. A total of 110 and 127 genes included 72 and 82 CDS, 34 and 37 tRNA, as well as four and eight rRNA genes. The reconstruction of the phylogenetic trees using maximum likelihood (ML) and Bayesian inference (BI) trees based on the concatenated CDS and internal transcribed spacer (ITS) sequences that were analyzed separately have revealed the same topology structure at genus level; Cratoxylum is monophyletic. However, C. formosum subsp. pruniflorum was not clustered together with its origin, raising doubt that it should be treated as a distinct species, C. pruniflorum based on molecular evidence that was supported by morphological descriptions.
Members of Aquilaria Lam. (Thymelaeaceae) are evergreen trees that are widely distributed in the Indomalesia region. Aquilaria is highly prized for its unique scented resin, agarwood, which is often the subject of unlawful trade activities. Survival of the tree is heavily threatened by destructive harvesting and agarwood poaching, leading to its protection under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Unfortunately, an efficient species identification method, which is crucial to aid in the conservation efforts of Aquilaria is lacking. Here, we described our search for a suitable specific DNA barcode for Aquilaria species using eight complete plastome sequences. We identified five highly variable regions (HVR) (matK-rps16, ndhF-rpl32, psbJ-petA, trnD, and trnT-trnL) in the plastomes. These regions were further analyzed using the neighbor-joining (NJ) method to assess their ability at discriminating the eight species. Coupled with in silico primer design, two potential barcoding regions, psbJ-petA and trnT-trnL, were identified. Their strengths in species delimitation were evaluated individually and in combination, via DNA barcoding analysis. Our findings showed that the combined dataset, psbJ-petA + trnT-trnL, effectively resolved members of the genus Aquilaria by clustering all species into their respective clades. In addition, we demonstrated that the newly proposed DNA barcode was capable at identifying the species of origin of six commercial agarwood samples that were included as unknown samples. Such achievement offers a new technical advancement, useful in the combat against illicit agarwood trades and in assisting the conservation of these valuable species in natural populations.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-023-03479-1.
The tropical climate in Malaysia provides an ideal environment for the rapid proliferation of Aedes mosquitoes, notably Aedes aegypti and Aedes albopictus, prominent vectors of dengue fever. Alarmingly, these species are increasingly developing resistance to conventional pesticides. This study aimed to evaluate the efficacy of Metarhizium anisopliae isolate HSAH5 spores, specifically on conidia (CO) and blastospores (BL), against Ae. albopictus larvae. The study centered on evaluating their pathogenic effects and the resultant changes in protein expression. Spore suspensions with varying concentrations were prepared for larvicidal bioassays, and protein expressions were analysed using liquid chromatography-mass spectrometry. Subsequently, protein annotation and network analysis were conducted to elucidate infection mechanisms and the proteomic response. Based on the lethal concentrations and time frames, CO exhibited faster larval mortality than BL at lower concentrations. Despite this, both spore types demonstrated comparable overall pathogenic effects. Results from the proteomic profiling revealed 150 proteins with varied expressions following exposure to Ae. albopictus extract, shedding light on distinct infection strategies between the spores. Gene Ontology enrichment and network analysis illustrated the diverse metabolic adaptations of M. anisopliae and interactions with mosquito larvae. This highlighted the complexity of host-pathogen dynamics and the significance of biosynthetic processes, energy storage, and cellular interaction pathways in disease progression. The BL network, consisting 80 proteins and 74 connections, demonstrates the intricate fungal mechanisms triggered by host stimuli. Conversely, the CO network, though smaller, displayed notable interconnectivity and concentrated involvement at the cell periphery, suggesting a deliberate strategy for initial host contact. This study offers valuable insights into proteome dynamics of M. anisopliae's BL and CO for managing mosquito populations and combating disease transmission, thereby significantly advancing public health and environmental conservation efforts.