Mangrove endophytic fungi: Biocontrol potential against Rhizoctonia solani and biofertilizers for fragrant rice cultivation.

The mangrove ecosystem has emerged as a fascinating source for exploring novel bioresources which have multiple applications in modern agriculture. This study evaluates the potential applications of mangrove endophytic fungi (MEF), such as biocontrol agents against Rhizoctonia solani and as biofertilizers for improving the yield of fragrant rice variety Malaysian Rice Quality 76 (MRQ76). Through the antagonism assays, it is observed that among the 14 MEF studied, 4 fungal isolates (Colletotrichum sp. MEFN02, Aspergillus sp. MEFN06, Annulohypoxylon sp. MEFX02 and Aspergillus sp. MEFX10) exhibited promising antagonistic effect against the pathogen R. solani compared to the chemical fungicide (Benomyl). These isolates also revealed significant production of enzymes, phytochemicals, indoleacetic acid (40.96 mg/mL) and ammonia (32.54 mg/mL) and displayed tolerance to salt and temperature stress up to 2000 mM and >40 °C respectively. Furthermore, employing the germination and pathogenicity test, inoculation of these endophytes showed lower percentage of disease severity index (DSI%) against R. solani, ranging from (24 %-46 %) in MRQ76 rice seedlings. The in-vivo experiments of soil and seed inoculation methods conducted under greenhouse conditions revealed that these endophytes enhanced plant growth (8-15 % increase) and increased crop yield (≥50 %) in comparison to control treatments. The current findings provide valuable insights into eco-friendly, cost-effective and sustainable alternatives for addressing R. solani infection and improving the agronomic performance of the fragrant rice cultivar MRQ76, contributing to food security.

A critical review on bioaerosols-dispersal of crop pathogenic microorganisms and their impact on crop yield.

Bioaerosols are potential sources of pathogenic microorganisms that can cause devastating outbreaks of global crop diseases. Various microorganisms, insects and viroids are known to cause severe crop diseases impeding global agro-economy. Such losses threaten global food security, as it is estimated that almost 821 million people are underfed due to global crisis in food production. It is estimated that global population would reach 10 billion by 2050. Hence, it is imperative to substantially increase global food production to about 60% more than the existing levels. To meet the increasing demand, it is essential to control crop diseases and increase yield. Better understanding of the dispersive nature of bioaerosols, seasonal variations, regional diversity and load would enable in formulating improved strategies to control disease severity, onset and spread. Further, insights on regional and global bioaerosol composition and dissemination would help in predicting and preventing endemic and epidemic outbreaks of crop diseases. Advanced knowledge of the factors influencing disease onset and progress, mechanism of pathogen attachment and penetration, dispersal of pathogens, life cycle and the mode of infection, aid the development and implementation of species-specific and region-specific preventive strategies to control crop diseases. Intriguingly, development of R gene-mediated resistant varieties has shown promising results in controlling crop diseases. Forthcoming studies on the development of an appropriately stacked R gene with a wide range of resistance to crop diseases would enable proper management and yield. The article reviews various aspects of pathogenic bioaerosols, pathogen invasion and infestation, crop diseases and yield.

CeO2 nanozyme mediated RPA/CRISPR-Cas12a dual-mode biosensor for detection of invA gene in Salmonella.

This study reports a novel biosensing system that leverages recombinase polymerase amplification (RPA) in conjunction with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a technology, integrated with a nanozyme (NZ) based on cerium dioxide (CeO2). With the integration of CeO2 NZ, a dual-mode detection platform could be developed for Salmonella detection using fluorometric and colourimetric assays. The CRISPR/Cas12a system, when activated in the presence of target DNA, could cleave the FAM-labelled probe to lead to a fluorometric response. Also, when the CeO2 NZ was introduced in the presence of H2O2, a colourimetric response was generated, directly proportional to the concentration of target DNA present. We hypothesise that adding highly reactive H2O2 within the post-CRISPR/Cas12a reaction system allows for increased release of hydroxyl free radicals within the mixture. Thus, the double recognition through NZ and the CRISPR/Cas12a system provided enhanced selectivity and sensitivity to the method. The proposed biosensor could successfully detect Salmonella at concentrations as low as 0.88 pg/µL and 1.28 pg/µL for fluorometric and colourimetric responses, respectively. Furthermore, the developed biosensor could be applied in real sample analysis of raw food samples (chicken, egg, and beef) to give a good recovery in the spiked food samples with varying concentrations of cultured bacterial DNA.

Recent trends and developments of PCR-based methods for the detection of food-borne Salmonella bacteria and Norovirus.

In recent years, rapid detection methods such as polymerase chain reaction (PCR) and quantitative real-time PCR (qPCR) have been continuously developed to improve the detection of food-borne pathogens in food samples. The recent developments of PCR and qPCR in the detection and identification of these food-borne pathogens are described and elaborated throughout this review. Specifically, further developments and improvements of qPCR are discussed in detecting Salmonella and norovirus. Promising advances in these molecular detection methods have been widely used to prevent human food-borne illnesses and death caused by the food-borne pathogens. In addition, this review presents the limitations and challenges of the detection methods which include conventional culture method and conventional PCR method in detecting Salmonella and norovirus. Furthermore, several advances of qPCR such as viability PCR (vPCR) and digital PCR (dPCR) have been discussed in the detection of Salmonella and norovirus. Good practice of analysis of the food-borne pathogens and other contaminants in the food industry as well as the advancement of molecular detection methods will help improve and ensure food safety and food quality.

The Role of Endophytes in Combating Fungal- and Bacterial-Induced Stress in Plants.

Plants are subjected to multifaceted stresses that significantly jeopardize crop production. Pathogenic microbes influence biotic stress in plants, which ultimately causes annual crop loss worldwide. Although the use of pesticides and fungicides can curb the proliferation of pathogens in plants and enhance crop production, they pollute the environment and cause several health issues in humans and animals. Hence, there is a need for alternative biocontrol agents that offer an eco-friendly mode of controlling plant diseases. This review discusses fungal- and bacterial-induced stress in plants, which causes various plant diseases, and the role of biocontrol defense mechanisms, for example, the production of hydrolytic enzymes, secondary metabolites, and siderophores by stress-tolerant fungi and bacteria to combat plant pathogens. It is observed that beneficial endophytes could sustain crop production and resolve the issues regarding crop yield caused by bacterial and fungal pathogens. The collated literature review indicates that future research is necessary to identify potential biocontrol agents that can minimize the utility of synthetic pesticides and increase the tenable agricultural production.

Agarwood-The Fragrant Molecules of a Wounded Tree.

Agarwood, popularly known as oudh or gaharu, is a fragrant resinous wood of high commercial value, traded worldwide and primarily used for its distinctive fragrance in incense, perfumes, and medicine. This fragrant wood is created when Aquilaria trees are wounded and infected by fungi, producing resin as a defense mechanism. The depletion of natural agarwood caused by overharvesting amidst increasing demand has caused this fragrant defensive resin of endangered Aquilaria to become a rare and valuable commodity. Given that instances of natural infection are quite low, artificial induction, including biological inoculation, is being conducted to induce agarwood formation. A long-term investigation could unravel insights contributing toward Aquilaria being sustainably cultivated. This review will look at the different methods of induction, including physical, chemical, and biological, and compare the production, yield, and quality of such treatments with naturally formed agarwood. Pharmaceutical properties and medicinal benefits of fragrance-associated compounds such as chromones and terpenoids are also discussed.

Identification of culturable petroleum-degrading bacteria and fungi from petroleum-contaminated sites in Brunei Darussalam.

Microbes that can be cultured and degrade petroleum are of particular interest for biotechnology such as bioremediation. This study aims to isolate and identify culturable petroleum-degrading bacteria and fungi from Brunei Darussalam, which has not previously been explored. A total of eight bacterial and nine fungal isolates that could degrade petroleum were obtained from petroleum-contaminated water or soil samples. DNA barcoding using 16S rRNA gene sequence identified five different bacterial genera which were Bacillus, Enterobacter, Micrococcus, Pseudoaltermonas and Pseudomonas. DNA barcoding using rRNA-ITS gene sequence identified nine different fungal taxa which were Aspergillus, Cladosporium, Exophiala, Flavodon, Hypocreales, Nectriaceae, Penicillium, Peniophora and Trichoderma. Biolog provided additional support to the identification of some isolates. This study is the first to report these unique microbes from Brunei Darussalam, which are of ecological and biotechnological value.

Isolation and characterization of a metal ion-dependent alkaline protease from a halotolerant Bacillus aquimaris VITP4.

A halotolerant bacterium Bacillus acquimaris VITP4 was used for the production of extracellular protease. Fractional precipitation using ammonium chloride was used to obtain the enzyme. The protease exhibited optimum activity at pH 8.0 and 40 degrees C and retained 50% of its optimal proteolytic activity even in the presence of 4 M NaCl, suggesting that it is halotolerant. The molecular mass of protease, as revealed by SDS-PAGE was found to be 34 kDa and the homogeneity of the enzyme was confirmed by gelatin zymography and reverse-phase HPLC. Upon purification, the specific activity of th enzyme increased from 533 U/mg to 1719 U/mg. Protease inhibitors like phenyl methane sulphonyl fluoride and 2-mercaptoethanol did not affect the activity of the enzyme, but EDTA inhibited the activity, indicating the requirement of metal ions for activity. Cu2, Ni2+ and Mn2+ enhanced the enzyme activity, but Zn2+, Hg2+ and Fe2+ decreased the activity, while Mg2+, Ca2+ and K+ had no effect on the enzyme activity. The protease was quite stable in the presence of cationic (CTAB), anionic (SDS) and neutral detergents (Triton X-100 and Tween-20) and exhibited antimicrobial activity against selected bacterial and fungal strains. The stability characteristics and broad spectrum antimicrobial activity indicated the potential use of this protease in industrial applications.