Known for its valuable agarwood, Aquilaria malaccensis Lam. is an evergreen tropical forest tree species endemic to the Indo-malesian region. Indiscriminate damaging and harvesting of the trees in the wild have resulted in it being listed in the CITES Appendix II for controlled trade and in the IUCN Red List as 'Vulnerable (VU)'. In this study, the complete chloroplast genome of A. malaccensis was assembled using data from high-throughput Illumina sequencing. The chloroplast genome was 174,832 bp in size, which included two inverted repeat regions of 42,091 bp each, separated by a large single copy region of 87,302 bp and a small single copy region of 3,348 bp. A total of 139 genes were predicted, including 39 tRNA, 8 rRNA, and 92 protein-coding genes. Phylogenetic analysis placed A. malaccensis within the family Thymelaeaceae. The chloroplast genome sequence of A. malaccensis offers a useful resource for future studies on the taxonomy and conservation of the threatened Aquilaria trees.
Rhizophora mucronata is an important ecosystem entity of the Malaysian mangrove forest. Since the species grows in a harsh environment, any organism that is isolated from this species would be of huge interest due to its potential in having novel bioactive compounds. In the present work, we isolated, identified and characterized, a total of 78 fungal isolates harboring inside the leaf tissues of R. mucronata. Molecular identification using the nuclear ribosomal DNA internal transcribe spacer (ITS) sequences returned with high similarity matches to known sequences in the GenBank. Maximum likelihood analysis revealed the phylogenetic relationship of all isolates from this study. Most of the dominating fungal endophytes were from the genera Pestalotiopsis, followed by Alternaria and Cladosporium. Six isolates representing the genera Alternaria, Fusarium, Nigrospora, Pestalotiopsis, Phoma, and Xylaria, were further screened for their antagonism activities. Dual culture test assay revealed their inhibition percentages against the phytopathogenic fungus Fusarium solani between 45-66%, and 0.8-23% when using non-volatile test assay. Of the six isolates, only Fusarium lateritium and Xylaria sp. showed antibacterial activities against the pathogenic bacteria, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, with the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) ranging from 0.5 to 2 mg/mL. The DPPH radical scavenging assay recorded a high level of antioxidant activity in Xylaria sp., 3-fold above that of F. lateritium. We demonstrate for the first time, two members belonging to the endophytic fungal community in the tropical mangrove species that have potential use as antagonists and antibacterial agents for future biotechnological applications.
Acacia mangium is an important wood for commercial products especially pulp and medium-density fibreboard. However, it is susceptible to Ceratocystis fimbriata infection, leading to Ceratocystis wilt. Therefore, the present work aimed to (i) establish the diversity of endophytic fungi in different plant parts of A. mangium,and (ii) evaluate the antifungal potentials of the isolated and identified endophytic fungi against C. fimbriata. Endophytic fungal identification was conducted by PCR amplification and sequencing of the internal transcribed spacer 1 (ITS1) and ITS4 regions of nuclear ribosomal DNA. A total of 66 endophytic fungi were successfully isolated from different parts of A. mangium; leaf (21), stem (13), petiole (12), root (9), flower (6), and fruit (5). The endophytic fungal isolates belonged to Ascomycota (95.5%) and Zygomycota (4.5%). For Ascomycota 13 genera were identified: Trichoderma (28.6%), Nigrospora (28.6%), Pestalotiopsis (12.7%), Lasiodiplodia (9.5%), Aspergillus (6.3%), Sordariomycetes (3%), and Neopestalotiopsis, Pseudopestalotiopsis, Eutiarosporella, Curvularia, Fusarium, Penicillium, and Hypoxylon each with a single isolate. For Zygomycota, only Blakeslea sp. (5%) was isolated. Against C. fimbriata, Trichoderma koningiopsis (AC 1S) from stem, Nigrospora oryzae (AC 7L) from leaf, Nigrospora sphaerica (AC 3F) from the flower, Lasiodiplodia sp. (AC 2 U) from fruit, Nigrospora sphaerica (AC 4P) from petiole, and Trichoderma sp. (AC 9R) from root exhibited strong inhibition for C. fimbriata between 58.33 to 69.23%. Thus, it can be concluded that certain endophytic fungi of A. mangium have the potential to be harnessed as anti-Ceratocystis agent in future biotechnological applications.