Zirconium dioxide nanoparticles (ZrO₂ NPs) have gained significant attention due to their excellent bioavailability, low toxicity, and diverse applications in the medical and industrial fields. In this study, ZrO₂ NPs were synthesized using zirconyl oxychloride and the aqueous leaf extract of Toddalia asiatica as a stabilizing agent. Analytical techniques, including various spectroscopy methods and electron microscopy, confirmed the formation of aggregated spherical ZrO₂ NPs, ranging from 15 to 30 nm in size, with mixed-phase structure composed of tetragonal and monoclinic structures. UV–visible spectroscopy showed a characteristic band at 281 nm with a bandgap energy of 3.7 eV, indicating effective stabilization by the phytochemicals in T. asiatica. EDX analysis revealed that the NPs contained 37.18 mol.% zirconium (Zr) and 62.82 mol.% oxygen. The ZrO₂ NPs demonstrated remarkable photocatalytic activity, degrading over 95% of methylene blue dye after 3 h of sunlight exposure. Additionally, the ZrO₂ NPs exhibited strong antibacterial effects, particularly against Gram-negative bacteria such as E. coli, and significant antioxidant activity, with low IC₅₀ values for hydroxyl radical scavenging. In conclusion, the green synthesis of ZrO₂ NPs using T. asiatica leaf extract is an effective, eco-friendly method that produces nanoparticles with remarkable antioxidant, antimicrobial, and photocatalytic properties, highlighting their potential for applications in water treatment, environmental remediation, and biomedicine.

Soon Young Ahn, Seon Ae Kim, and Hae Keun Yun. Plant Breeding and Biotechnology 2016;4:61-70. https://doi.org/10.9787/PBB.2016.4.1.61

Recent studies have shown that the expression of genes related to the synthesis of flavonoids, such as the phenylalanineammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and stilbene synthase (STS) genes were induced in response to different signaling molecules and Botrytis cinerea inoculation in grapevine leaves. Therefore, in the present study, the nucleotide and deduced amino acid sequences of STS genes from cultivars Campbell Early and Kyoho were compared. The deduced amino acid sequences of VlKSTS12, VlKSTS11, VICESTS13, and VlKSTS1 showed 100 % homology to VlCESTS12, VlCESTS11, VICESTS24, and VlKSTS13, respectively, in Campbell Early and Kyoho. In addition, the maximum transcription was observed 6 h after chemical treatments. In Campbell Early, the transcription of PAL, CHS, and CHI was higher in leaves treated with ethephon than in those treated with hydrogen peroxide, methyl jasmonate, and salicylic acid. The PAL, CHS, and CHI genes were more induced in Campbell Early than in Kyoho. The mRNA content of STS genes started to increase at 6 h and peaked at 48 h after the treatments. In Kyoho leaves, the expression of STSs was highly up-regulated at 1 h and peaked at 6 h after the treatments. The expression of the STS genes was induced in both the cultivars in leaves inoculated with B. cinerea. STS11 and STS12 showed differential expression patterns from STS1, STS24, and STS13 in Campbell Early leaves inoculated with B. cinerea.

Identification and Expression Profiles of Six Transcripts Encoding Carboxylesterase Protein in Vitis flexuosa Infected with Pathogens Botrytis cinerea;disease resistance;Elsinoe ampelina;hypersensitive response;Rhizobium vitis; Plants protect themselves from pathogen attacks via several mechanisms, including hypersensitive cell death. Recognition of pathogen attack by the plant resistance gene triggers expression of carboxylesterase genes associated with hypersensitive response. We identified six transcripts of carboxylesterase genes, Vitis flexuosa carboxylesterase 5585 (VfCXE5585), Vf-CXE12827, VfCXE13132, VfCXE17159, VfCXE18231, and VfCXE47674, which showed different expression patterns upon transcriptome analysis of V. flexuosa inoculated with Elsinoe ampelina. The lengths of genes ranged from 1,098 to 1,629 bp, and their encoded proteins consisted of 309 to 335 amino acids. The predicted amino acid sequences showed hydrolase like domains in all six transcripts and contained two conserved motifs, GXSXG of serine hydrolase characteristics and HGGGF related to the carboxylesterase family. The deduced amino acid sequence also contained a potential catalytic triad consisted of serine, aspartic acid and histidine. Of the six transcripts, Vf-CXE12827 showed upregulated expression against E. ampelina at all time points. Three genes (VfCXE5585, VfCXE12827, and VfCXE13132) showed upregulation, while others (VfCXE17159, VfCXE18231, and VfCXE47674) were down regulated in grapevines infected with Botrytis cinerea. All transcripts showed upregulated expression against Rhizobium vitis at early and later time points except VfCXE12827, and were downregulated for up to 48 hours post inoculation (hpi) after upregulation at 1 hpi in response to R. vitis infection. All tested genes showed high and differential expression in response to pathogens, indicating that they all may play a role in defense pathways during pathogen infection in grapevines.