Plants

With-No-Lysine (WNK) kinases constitute a subgroup within the serine/threonine protein kinase family, characterized by the absence of a catalytic lysine residue in the kinase subdomain II located in their N-terminal region. These kinases play critical roles in regulating plant growth, development, and responses to abiotic stressors. However, members of the WNK and their responses to heat stress in pepper (Capsicum annuum L.) remain unexplored. In the present study, we identified eleven WNK genes within the genome of pepper cultivar ‘UCD-10X-F1’ and designated them CaWNK1 to CaWNK11 according to their chromosomal positions. Comprehensive analyses were conducted to elucidate their phylogenetic relationships, chromosomal distribution, collinearity, gene structure, protein properties, and cis-acting elements within promoter regions. The findings revealed that the CaWNK gene family segregates into five distinct subgroups. Comparative genomic analysis identified eleven and nine segmental duplication gene pairs between pepper and tomato and between pepper and Arabidopsis, respectively. Within the pepper genome, two pairs of segmentally duplicated genes and two pairs of tandemly repeated genes were also detected. The CaWNK gene sequences in pepper exhibited a high degree of conservation; however, variations were observed in the number of introns and exons. Analysis of the promoter regions revealed an abundance of cis-acting elements associated with growth and development, stress responses, and hormone regulation. Subsequent transcriptomic analyses demonstrated that CaWNK genes displayed tissue-specific expression patterns and differential expression levels following treatments with exogenous plant hormones and abiotic stresses. Notably, the expression of CaWNK6 was significantly up-regulated under heat stress conditions. To elucidate the functional role of CaWNK6, virus-induced gene silencing (VIGS) was employed to suppress its expression in pepper seedlings. Silencing of CaWNK6 resulted in disrupted tissue architecture, stomatal closure, and diminished heat tolerance. These phenotypic changes correlated with excessive accumulation of reactive oxygen species (ROS), reduced activity of antioxidant enzymes, and down-regulation of heat shock factor (HSF) genes in the silenced plants. Collectively, these findings offer valuable insights into the functional roles of CaWNK genes and hold significant implications for the development of novel heat-tolerant pepper cultivars.

This study aimed to determine the antifungal activity of various compounds and develop a novel antifungal formulation against fungal pathogens, including Alternaria alternata, Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer. A total of 32 plant-derived secondary metabolites and three extracts (dichloromethane, ethyl acetate, and methanol) from Lawsonia inermis, Juglans regia, and Drosera intermedia were screened at a concentration of 250 ppm. The chemical composition of the D. intermedia ethyl acetate extract was characterized using chromatographic techniques. Subsequently, an emulsifiable concentrate formulation from this extract was prepared, and its efficacy was evaluated at concentrations ranging from 250 to 2000 ppm. The D. intermedia ethyl acetate extract was found to contain three flavonoids (1.4%) and three naphthoquinones (2.8%). The formulation exhibited optimal effect at 1000 ppm. Overall, the high efficacy of the formulation containing the dried D. intermedia extract (10:1, ethyl acetate) positions it as a promising and viable alternative to synthetic fungicides.

The plant cell wall is essential for maintaining cellular structure and regulating physiological processes such as growth and stress tolerance. Cell wall dynamics are largely mediated by cell wall-modifying enzymes, including glycoside hydrolases (GHs). In this study, we explored GH5 family members in Oryza sativa L. and identified 17 genes encoding GH5 proteins, classified into three subfamilies: GH5_7, GH5_11, and GH5_14. Characterization of the GH5_11 protein encoded by the LOC_Os04g40510 gene involved the subcellular localization of a GFP-tagged protein, gene expression analysis during germination, and phenotypic evaluation of transgenic plants. The protein was synthesized through the secretory pathway with expression in seeds, predominantly in the endosperm. Overexpression of LOC_Os04g40510 resulted in altered seed morphology, increased chalkiness, and reduced seed set. Although the overall seed number increased, the seed mass was reduced for the knock-down lines. These data suggest that LOC_Os04g40510 may play a role in fertility and endosperm development. Our findings provide new insights into the biological function of GH5_11 enzymes in rice.