Bio-synthesis and characterization of silver nanoparticles from Trichoderma species against cassava root rot disease.

Cassava root rot disease caused by the fungal pathogens Fusarium solani and Lasiodiplodia theobromae produces severe damages on cassava production. This research was conducted to produce and assess silver nanoparticles (AgNPs) synthesized by Trichoderma harzianum for reducing root rot disease. The results revealed that using the supernatants of T. harzianum on a silver nitrate solution changed it to reddish color at 48 h, indicating the formation of AgNPs. Further characterization was identified using dynamic light scattering (DLS) and scanning electron microscope (SEM). DLS supported that the Z-average size is at 39.79 nm and the mean zeta potential is at - 36.5 mV. SEM revealed the formation of monodispersed spherical shape with a diameter between 60-75 nm. The antibacterial action of AgNPs as an antifungal agent was demonstrated by an observed decrease in the size of the fungal colonies using an increasing concentration of AgNPs until the complete inhibition growth of L. theobromae and F. solani at > 58 µg mL-1 and at ≥ 50 µg mL-1, respectively. At in vitro conditions, the applied AgNPs caused a decrease in the percentage of healthy aerial hyphae of L. theobromae (32.5%) and of F. solani (70.0%) compared to control (100%). The SR-FTIR spectra showed the highest peaks in the first region (3000-2800 cm-1) associated with lipids and fatty acids located at 2962, 2927, and 2854 cm-1 in the AgNPs treated samples. The second region (1700-1450 cm-1) consisting of proteins and peptides revealed the highest peaks at 1658, 1641, and 1548 cm-1 in the AgNPs treated samples. The third region (1300-900 cm-1), which involves nucleic acid, phospholipids, polysaccharides, and carbohydrates, revealed the highest peaks at 1155, 1079, and 1027 cm-1 in the readings from the untreated samples. Finally, the observed root rot severity on cassava roots treated with AgNPs (1.75 ± 0.50) was significantly lower than the control samples (5.00 ± 0.00).

The Changes in Metabolites, Quality Components, and Antioxidant Activity of Tea (Camellia sinensis) Infected with Exobasidium vexans by Applying UPLC-MS/MS-Based Widely Targeted Metabolome and Biochemical Analysis.

Blister blight infection with Exobasidium vexans is one of the most destructive foliar diseases that seriously affect the quality and yield of tea. This research investigated the metabolite changes of healthy and infected leaves on tea cultivar 'Fuding Dabaicha' and further explored the potential antimicrobial substances against E. vexans infection. In total, 1,166 compounds were identified during the entire course of an infection, among which 73 different common compounds were significantly accumulated involved in the important antimicrobial substances of flavonoids and phenolic acids, including kaempferol (3,5,7,4'-tetrahydroxyflavone), kaempferol-3-O-sophoroside-7-O-glucoside, phloretin, 2,4,6-trihydroxybenzoic acid, galloylprocyanidin B4, and procyanidin C1 3'-O-gallate, which indicated that these metabolites might positively dominate resistance to E. vexans. Furthermore, relevant biological pathways, such as the flavone and flavonol biosynthesis, flavonoid biosynthesis, and phenylpropane pathways, were more closely related to resistance to E. vexans. Additionally, total flavonoids, phenolics, alkaloids, and terpenoids contributing to antimicrobial and antioxidant capacity were significantly altered during four different infection periods, especially the Leaf_S2 stage (the second stage of infection), in which the most concentration accumulated. The leaves affected by E. vexans infection at the second stage had the relatively highest antioxidant activity. Accordingly, this study provides a theoretical support for and comprehensive insights into the effects on the metabolite changes, tea quality components, and antioxidant activity of blister blight caused by E. vexans.

Flour on Gluten-Free Muffins from Different Edible Cassava Varieties in Thailand.

In Thailand new edible cassava varieties have been developed to be used in the food industry. The aim of this research was to analyze the difference between flour from three cassava varieties and to evaluate the suitability and quality of flour for gluten-free muffins. The physico-chemical properties of flour from three varieties were studied. The results showed the moisture content of flour was between 10.65 ± 0.01 and 10.85 ± 0.45%. Total protein content was highly significant with a difference of 1.97 ± 0.00%, 2.15 ± 0.01%, and 2.18 ± 0.01%, respectively. Moreover, ash and fat in each flour were highly significant. Amylose content was 19.93 ± 0.47%, and the viscosity was 6286.00 ± 1.52 mPa.s. The color of flour values of L* a* b* value was not statistically different in each variety of flour. Fourier transform infrared spectroscopy (FTIR) analysis was used for the biochemical change in flour. The PCA and cluster analysis results revealed that cassava flour from Pirun 6 was different from Pirun 2 and Pirun 4. After that, the test using selected cassava flour from Pirun 6 to test the physical properties and sensory attributes of gluten-free muffins compared with wheat flour found that gluten-free muffins were overall better than basic muffins.