Immunolocalization of a class III chitinase in two muskmelon cultivars reacting differently to Fusarium oxysporum f. sp. melonis

Bioinformatics and Expression Analysis of the Chitinase Genes in Strawberry (Fragaria vesca) and Functional Study of FvChi-14

Plant chitinases (EC 3.2.1.14) are pathogenesis-related (PR) proteins and are well studied in many plant species. However, little is known about the genomic organization and expression of chitinase genes in strawberries (Fragaria vesca). Here, 23 FvChi genes were identified in the genome of strawberry (F. vesca) and divided into GH18 and GH19 subfamilies based on phylogenetic relationships. A detailed bioinformatics analysis of the FvChi genes was performed, including gene physicochemical properties, chromosomal location, exon-intron distribution, domain arrangement, and subcellular localization. Twenty-two FvChi genes showed upregulation after Colletotrichum gloeosporioides infection. Following the exogenous application of SA, FvChi-3, 4, and 5 showed significant changes in expression. The ectopic expression of FvChi-14 in Arabidopsis thaliana increased resistance to C. higginsianum via controlling the SA and JA signaling pathway genes (AtPR1, AtICS1, AtPDF1.2, and AtLOX3). The FvChi-14 protein location was predicted in the cell wall or extracellular matrix. We speculate that FvChi-14 is involved in disease resistance by regulating the SA and JA signaling pathways. The findings of this study provide a theoretical reference for the functional studies of FvChi genes and new candidates for strawberry stress resistance breeding programs.

mRNA expression of EgCHI1, EgCHI2, and EgCHI3 in oil palm leaves (Elaeis guineesis Jacq.) after treatment with Ganoderma boninense pat. and Trichoderma harzianum Rifai

Background. Basal stem rot (BSR) disease caused by the fungus Ganoderma boninense is the most serious disease affecting the oil palm; this is because the disease escapes the early disease detection. The biocontrol agent Trichoderma harzianum can protect the disease only at the early stage of the disease. In the present study, the expression levels of three oil palm (Elaeis guineensis Jacq.) chitinases encoding EgCHI1, EgCHI2, and EgCHI3 at 2, 5, and 8 weeks inoculation were measured in oil palm leaves from plants treated with G. boninense or T. harzianum alone or both. Methods. The five-month-old oil palm seedlings were treated with Gano-wood blocks inoculum and trichomulch. Expression of EgCHI1, EgCHI2, and EgCHI3 in treated leaves tissue was determined by real-time PCR. Results. Oil palm chitinases were not strongly expressed in oil palm leaves of plants treated with G. boninense alone compared to other treatments. Throughout the 8-week experiment, expression of EgCHI1 increased more than 3-fold in leaves of plants treated with T. harzianum and G. boninense when compared to those of control and other treated plants. Conclusion. The data illustrated that chitinase cDNA expression varied depending on tissue and the type of treatment.