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Aims: Leaf blight disease caused by Pantoea spp. reduces rice yields in numerous nations. However, the exact strategy to combat Pantoea spp. has yet to be determined. Bactronophorus thoracites is a promising source of natural antimicrobial agents due to their potential as a substrate to generate peptides with high antimicrobial activity. This study determined the effects of lactic acid fermentation using Lactobacillus casei ATCC334 as a starter culture on antimicrobial activity against rice pathogens, proximate composition, and amino acid profiles from B. thoracites crude extract. Methodology and results: Bactronophorus thoracites was washed and deshelled to collect the flesh and homogenised at 4 °C before freeze-drying. The freeze-dried samples were fermented with L. casei for 4 to 8 days at 37 °C. The antimicrobial activity, MIC and MBC were determined using a spectrometer. The fermented protein was subjected to proximate and amino acid analyses. The antimicrobial activity of fermented B. thoracites protein (FBTP) was significantly (p<0.05) decreased with the increased fermentation days (from 4 to 8 days). The antimicrobial activity was also increased when the glucose concentration increased from 2% to 3%. However, raising the glucose concentration to 4% decreased the antimicrobial activity. The antimicrobial activity was significantly (p<0.05) increased when the substratewater (S/W) ratio increased from 0.84% to 0.96%. The FBTP (4 days, 3% glucose concentration and 0.96% S/W ratio) showed high antimicrobial activity against Pantoea ananatis and P. stewartii. The MIC and MBC values for FBTP were 500 µg/mL and 250 µg/mL against P. ananatis and P. stewartii. The zones of inhibition value for FBTP were 16.0 ± 0.5 mm (1000 µg/mL) and 9.33 ± 0.57 mm (500 µg/mL) for P. ananatis, and 11.7 ± 0.61 mm (1000 µg/mL), 9.33 ± 0.58 mm (500 µg/mL) and 7.17 ± 0.77 mm (250 µg/mL) for P. stewartii. The proximate composition and amino acid profiles of the freeze-dried protein hydrolysate powder were characterised. FBTP produced a higher value of protein (61.56%) and ash (32.38%) and a lower value of total fat (0.273%) and carbohydrates (6.27%) than the B. thoracites crude extract. Total amino acid content was 39.480 g/100 g in B. thoracites crude extract and 155.442 g/100 g in FBTP. The essential amino acid glutamine was the most abundant in B. thoracites crude extract and methionine in FBTP. Conclusion, significance and impact of study: This study showed that lactic acid fermentation could produce FBTP using L. casei with improved functional characteristics and as a source of a natural antimicrobial agent against rice pathogens. [ABSTRACT FROM AUTHOR]

Overexploitation in search of its valuable non-wood fragrance product has put pressure on the survival of the endangered Aquilaria trees in the wild. In this study, the pattern of genetic variation among wild populations was measured to aid in designing useful strategies for in situ conservation. We sequenced the internal transcribed spacer (ITS) of the nuclear region of 19 wild Aquilaria malaccensis populations from different states in Peninsular Malaysia, and compared the sequence with the same species residing outside of Malaysia, mainly from the Assam region in India and Sumatra in Indonesia. This widely distributed species is found in the Indomalesian region and is a major source of agarwood. In addition, we included five wild Aquilaria hirta populations for semblance purposes. Intraspecific variations were not found within A. malaccensis and A. hirta populations in Peninsular Malaysia. Interestingly, Single Nucleotide polymorphisms (SNPs) were identified when comparing A. malaccensis from three geographical regions, with a total of 25 SNPs detected. We imply that geographical segregation is a contributing factor toward genetic variation in A. malaccensis. This is the first report on utilizing the ITS region for analysing genetic variation in A. malaccensis of various geographical regions. The molecular information obtained in this study will serve as a useful reference in designing in situ programmes for this endangered species. [ABSTRACT FROM AUTHOR]

Rigidoporus microporus is the fungus accountable for the white root rot disease that is detrimental to the rubber tree, Hevea brasiliensis. The pathogenicity mechanism of R. microporus and the identity of the fungal proteins and metabolites involved during the infection process remain unclear. In this study, the protein and metabolite profiles of two R. microporus isolates, Segamat (SEG) and Ayer Molek (AM), were investigated during an in vitro interaction with H. brasiliensis. The isolates were used to inoculate H. brasiliensis clone RRIM 2025, and mycelia adhering to the roots of the plant were collected for analysis. Transmission electron microscope (TEM) images acquired confirms the hyphae attachment and colonization of the mycelia on the root of the H. brasiliensis clones after 4 days of inoculation. The protein samples were subjected to 2-DE analysis and analyzed using MALDI-ToF MS/MS, while the metabolites were extracted using methanol and analyzed using LC/MS-QTOF. Based on the differential analyses, upregulation of proteins that are essential for fungal evolution such as malate dehydrogenase, fructose 1,6-biphosphate aldolase, and glyceraldehyde-3-phosphate dehydrogenase hints an indirect role in fungal pathogenicity, while metabolomic analysis suggests an increase in acidic compounds which may lead to increased cell wall degrading enzyme activity. Bioinformatics analyses revealed that the carbohydrate and amino acid metabolisms were prominently affected in response to the fungal pathogenicity. In addition to that, other pathways that were significantly affected include “Protein Ubiquitination Pathway,” Unfolded Protein Response,” “HIFα Signaling,” and “Sirtuin Signaling Pathway.” The identification of responsive proteins and metabolites from this study promotes a better understanding of mechanisms underlying R. microporus pathogenesis and provides a list of potential biological markers for early recognition of the white root rot disease. [ABSTRACT FROM AUTHOR]