Application Of Secondary Metabolites Research Articles

A Genome-Wide Comparison of Rice False Smut Fungus Villosiclava virens Albino Strain LN02 Reveals the Genetic Diversity of Secondary Metabolites and the Cause of Albinism.

Rice false smut (RFS) caused by Villosiclava virens (anamorph: Ustilaginoidea virens) has become one of the most destructive fungal diseases to decrease the yield and quality of rice grains. An albino strain LN02 was isolated from the white RFS balls collected in the Liaoning Province of China in 2019. The strain LN02 was considered as a natural albino mutant of V. virens by analyzing its phenotypes, internal transcribed spacer (ITS) conserved sequence, and biosynthesis gene clusters (BGCs) for secondary metabolites. The total assembled genome of strain LN02 was 38.81 Mb, which was comprised of seven nuclear chromosomes and one mitochondrial genome with an N50 value of 6,326,845 bp and 9339 protein-encoding genes. In addition, the genome of strain LN02 encoded 19 gene clusters for biosynthesis of secondary metabolites mainly including polyketides, terpenoids and non-ribosomal peptides (NRPs). Four sorbicillinoid metabolites were isolated from the cultures of strain LN02. It was found that the polyketide synthase (PKS)-encoding gene uspks1 for ustilaginoidin biosynthesis in strain LN02 was inactivated due to the deletion of four bases in the promoter sequence of uvpks1. The normal uvpks1 complementary mutant of strain LN02 could restore the ability to synthesize ustilaginoidins. It demonstrated that deficiency of ustilaginoidin biosynthesis is the cause of albinism for RFS albino strain LN02, and V. virens should be a non-melanin-producing fungus. This study further confirmed strain LN02 as a white phenotype mutant of V. virens. The albino strain LN02 will have a great potential in the development and application of secondary metabolites. The physiological and ecological functions of ustilaginoidins in RFS fungus are needed for further investigation.

Remediation of chlorpyrifos-contaminated soils by crude secondary metabolites of Trichoderma harzianum T213 and its effect on maize growth

Abstract. Soesanto L, Susanti RA, Mugiastuti E, Manan A, Sastyawan MWR, Maryanto J. 2022. Remediation of chlorpyrifos-contaminated soils by crude secondary metabolites of Trichoderma harzianum T213 and its effect on maize growth. Biodiversitas 23: 2464-2470. The study was conducted to determine the role of Trichoderma harzianum T213 crude secondary metabolites on the growth of maize plants and the reduction of chlorpyrifos on contaminated soils. A randomized block design was used in this study with four treatments. The treatments applied on chlorpyrifos contaminated soil were: without the application of secondary metabolites (0%) and the application of T. harzianum T213 crude secondary metabolites at the concentration of 50, 100, and 150%. Variables observed were residual levels of insecticide in maize, plant height difference, number of leaves, plant fresh weight, and root length. The results showed that the application of T. harzianum T213 crude secondary metabolites effectively increased plant growth, including plant height, the number of leaves, plant fresh weight, and root length compared to control on chlorpyrifos-contaminated soil. The highest percentage (99.54%) of the reduction of chlorpyrifos residue was the application of 100% T. harzianum T213 crude secondary metabolites. It was followed by applying 50 and 150% T. harzianum T213 crude secondary metabolites by 99.39 and 99.14%, respectively.

Progress on application of secondary metabolites from bamboo in controlling diseases and keeping freshness of fruits and vegetables

Progress on application of secondary metabolites from bamboo in controlling diseases and keeping freshness of fruits and vegetables

Optimization of electroporation-based multiple pulses and further improvement of transformation efficiency using bacterial conditioned medium for Nannochloropsis salina

Development of transgenic strains of microalgae is necessary to obtain microalgal strains that are capable of producing high levels of oils and a variety of bio-products. However, microalgae have a much lower transformation efficiency in comparison to other micro-organisms due to the presence of thick cell walls. Here, a two-pronged approach for optimizing the electroporation parameters combined with the application of secondary metabolites from myxobacteria to weaken the cell wall was used to maximize the transformation efficiency of Nannochloropsis salina (Eustigmatophyceae). When the electroporation parameters were set at 50 pulses of square waves at a field strength of 12,000 V cm−1, a transformation efficiency of up to 53 per 108 cells was achieved for N. salina in the early exponential phase of growth. Next, cultivation of the microalgae using bacterial conditioned F2N medium containing 10% supernatant of the myxobacteria strain DZ2 resulted in a moderate inhibition of the growth rate and distinctive morphological changes. Flow cytometry confirmed an increase in the overall cell size as well as granularity. When the bacterial medium conditioned cells were employed for transformation under optimized electroporation conditions, the transformation efficiency improved 2.71-fold up to 144 per 108 cells. Taken together, a combinatory approach for electroporation using high field strength square wave pulses and conditioning cells with myxobacterial supernatant is a promising method for the efficient genetic transformation of microalgae.

The application of secondary metabolites in the study of sorghum insect resistance

Insect attack is one of the main factors for limiting the production of rice and sorghum. To improve resistance to pests of rice and sorghum will be of great significance for meliorating their production and quality. However, the source and material of anti-pest was scarce. In this study, we will study on the expression patterns of hydrocyanic acid biosynthesis relative genes in sorghum firstly. And we will also genetically transform them into rice and sorghum by specific and constitutive promoters and verify their pest-resistant ability. Finally, high pest-resistant genetically modified new sorghum cultivars will be bred with favorable comprehensive agronomic traits.

Phenolic Metabolites from Humicola grisea var. thermoidea

Antibiotics have been useful in our battles against infectious bacteria and fungi for over 50 years. However, many antibiotics are used commercially, or are potentially useful, in medicine for activities other than their antibiotic action. They are used as antitumor agents, immunosuppressive agents, hypocholesterolemic agents, enzyme inhibitors, antimigraine agents, and antiparasitic agents. A number of these products were first discovered as antibiotics which failed in their development as such, or as mycotoxins. In addition to the above alternative applications, new powerful antibiotics have been discovered and commercialized in recent years and others are in clinical testing. A few successful secondary metabolites appear to have no antibiotic activity [1]. The aim of this work was to evaluate the antimicrobial activity and applications of secondary metabolites produced by Humicola grisea var thermoidea. The production of secondary metabolites was carried out by cultivating 106 spores/g in solid medium (rice) at 40°C for 60 days. The culture was filtered and submitted to the process of liquid-liquid partition with organic solvents. Then, the dicloromethane extract was concentrated under vacuum, and submitted to vacuum liquid chromatography technique, followed by preparative TLC for the isolation of dimethyl terefthalate (DMT), which was elucidated by spectroscopy means (NMR). This compound was submitted to antibacterial assay to determine the minimum inhibitory concentration (MIC) against Escherichia coli, Kocuria rhizophila, Pseudomonas aeruginosa and Staphylococcus aureus. The interval of concentrations evaluated was from 50 µg/mL to 400 µg/mL. The obtained MIC values against K. rhizophila and E. coli were 350 µg/mL. The dimethyl tereftalate is used for production by biopolymer polytrimethylterefthalate (PTT), when polymerized with 1,3-propanediol. Nowadays DMT is obtained from petroleum. Therefore, the production of this compound from fermentative means, using microorganisms would be a promising strategy. Acknowledgment: Financial Support: FAPESP (Grant 01/07935-6) and FCFRP/USP.