Terpenoid Profiling of Thai Strain Cannabis Leaves (Cannabis sativa L. subsp. sativa) by Headspace (HS) Couple with GC/MS

Introduction:  Cannabis terpenoids, especially volatile terpenes, were used for the classification of cannabis strains. The leaves of Cannabis sativa L. subsp. sativa Thai strain ‘Hang Krarok’ are used legally in traditional Thai medicines, cosmetics, and food ingredients in Thailand under the control of the tetrahydrocannabinol (if lower than 0.2% dry weight). One of the specific characteristics of this plant is the volatile oil which consists of mono-and the sesqui-terpenoids. Materials and methods: Fresh cannabis leaves were ground and 1 g samples were kept in gas chromatography/mass spectrometry glass vials at 4 °C prior to measurement using headspace. Results: More than 50 terpenoids were identified from the fresh leaves in the cannabis samples. The major compounds were ?–ocimene, L–limonene, terpinolene, p–cymenene, ?–(E)–caryophyllene, (Z,E)–?–farnesene, ?–bisabolene, and (E)–?–bisabolene.  Conclusion: The variation in the unique terpenoids in the Thai strain could be used in novel medicines and food and cosmetic products

A Rhizobacterium, <i>Streptomyces albulus</i> Z1-04-02, Displays Antifungal Activity against Sclerotium Rot in Mungbean

Sclerotium rot causes damping-off and stem rot in seedlings and mature mungbeans, which negatively impacts cultivation. The use of a rhizobacterium to control soil-borne diseases is an alternative method to the excess use of synthetic fungicides; therefore, this study aims to screen rhizosphere actinobacteria with fungicidal activities against Sclerotium rolfsii, the pathogen that causes sclerotium rot in mungbeans. Primary screening showed that the Streptomyces sp. isolate Z1-04-02 displayed the highest effectiveness against S. rolfsii in dual culture plates, with a percentage inhibition of 74.28%. An assay containing enzymes that degrade cell walls, of the cell-free culture filtrate (CF) of Z1-04-02, showed that the activities of chitinase and β-1,3-glucanase were 0.0209 and 1.0210 U/mL, respectively, which was significantly higher than that of the control (media alone). The cell-free CF of Z1-04-02, incubated at 37 °C and 100 °C, using agar well diffusion, effectively inhibited the growth of S. rolfsii with inhibition percentages of 37.78% and 27.78%, respectively. Solid-phase microextraction (SPME) was applied to trap volatiles released from Z1-04-02 and gas chromatography–mass spectrometry (GC/MS); volatile antifungal compounds were tentatively identified as bicyclic monoterpene (1R)-(-)-myrtenal. The application of the cell-free CF, and the spore suspension of Z1-04-02, showed disease severity indexes (DSIs) of 12.5% and 8.25%, respectively, which were significantly lower than those showing inoculation by S. rolfsii alone. The identification of this strain by morphology, biochemistry tests, and 16s rDNA sequences revealed that Z1-04-02 was Streptomyces albulus. This finding revealed that S. albulus Z1-04-02 displayed diverse fungicidal activities against S. rolfsii, and it has the potential to act as a biological control agent in terms of inhibiting sclerotium rot in mungbeans

Rice Sesquiterpene Plays Important Roles in Antixenosis against Brown Planthopper in Rice

The rice sesquiterpene synthase II gene (OsSTPS2, LOC_Os04g27430), which is involved in the antixenosis defense mechanism of rice against brown planthopper (BPH) infestation, was identified in the BPH-resistant rice variety Rathu Heenati (RH). In contrast, the gene was not functional in the BPH-susceptible rice variety KDML105 (KD). Single-nucleotide polymorphisms (SNPs) in the promoter region and in exon 5 of the gene and a seven amino acid deletion in the deduced protein sequence are suggested as factors that negatively regulate the function of the gene. Sequence analysis of the promoter region and expression analysis of the OsSTPS2 gene in several rice genotypes revealed the correlation of SNPs of the ATHB-1, SBE1, and P-factor with the expression of the gene. Genomic and complementary DNA (cDNA) sequence analysis at exon 5 of the gene showed that the 21 bp deletion naturally occurred in several rice genotypes. The antixenosis of the BPH feeding preference (AFP) of rice varieties differed in the seven amino acid deletion lesion of the gene, suggesting that the seven amino acid deletion negatively controls the antixenosis mechanism during BPH infestation. Analysis of the plant volatile compounds released after BPH infestation suggested that E-β-farnesene (EBF) is the major product of the OsSTPS2 gene

Volatile Organic Compound from Trichoderma asperelloides TSU1: Impact on Plant Pathogenic Fungi

Soil microorganisms are well studied for their beneficial effects on plant growth and their impact on biocontrol agents. The production of volatile antifungal compounds emitted from soil fungi is considered to be an effective ability that can be applied in biofumigants in the control of plant diseases. A soil fungus, Trichoderma asperelloides TSU1, was isolated from flamingo flower cultivated soil and identified on the basis of the morphology and molecular analysis of the internal transcribed spacer (ITS), rpb2, and tef1-α genes. To test T. asperelloides TSU1-produced volatile organic compounds (VOCs) with antifungal activity, the sealed plate method was used. The VOCs of T. asperelloides TSU1 inhibited the mycelial growth of fungal pathogens that were recently reported as emerging diseases in Thailand, namely, Corynespora cassiicola, Fusarium incarnatum, Neopestalotiopsis clavispora, N. cubana, and Sclerotium rolfsii, with a percentage inhibition range of 38.88–68.33%. Solid-phase microextraction (SPME) was applied to trap VOCs from T. asperelloides TSU1 and tentatively identify them through gas chromatography–mass spectrometry (GC/MS). A total of 17 compounds were detected in the VOCs of T. asperelloides TSU1, and the dominant compounds were identified as fluoro(trinitro)methane (18.192% peak area) and 2-phenylethanol (9.803% peak area). Interestingly, the commercial 2-phenyethanol showed antifungal activity against fungal pathogens that were similar to the VOCs of T. asperelloides TSU1 by bioassay. On the basis of our study’s results, T. asperelloides TSU1 isolated from soil displayed antifungal abilities via the production of VOCs responsible for restricting pathogen growth