Persicaria minor is one of the native aromatic plants in Malaysia and widely used in traditional foods and medicines. Previous studies have shown that treatment of P. minor with jasmonic acid upregulated genes involved in the secondary metabolites production and also gene encoding an F-box protein named PmFbox-1. It is known that F-box proteins play important roles in gene expression regulatory. However, the function of PmF-box1 protein is still unknown. In this study, the full length cDNA sequence of PmF-box1, with NCBI accession number JQ429325, consisting of 2768 bp was isolated followed by characterization of the deduced protein sequence of 487 amino acids. The putative F-box protein belongs to Kelch repeat-containing F-box protein family (KFB) and has a moderate level of homology with other F-box proteins from different organisms, showing a maximum identity score of 60 % with an F-box motif and two conserved kelch repeat motifs. Time course semi-quantitative reverse-transcriptase PCR gel image analyses showed that PmF-box1 was induced after JA treatment, indicating that PmF-box1 is a JA inducible gene. PmF-box1 also differentially expressed in different tissues after treatment with JA, indicating a spatial regulation of its activity. Interestingly, there was high correlation in the expression pattern between PmF-box1 and PmADH1 (P. minor Alcohol dehydrogenase 1) (R= 0.90 ± 0.05) after treatment with 150 µM JA, indicating that PmF-box1 possibly involves in regulating the activity of PmADH1. The content of hexanal was significantly increased in JA-treated plants and even higher in JA plus SA-treated plants. The level of six carbon alcohols was increased at 48 hours after JA treatment, consistent with the upregulation of PmADH1 in JA treated plants. These results suggest that PmF-box1 encodes a KFB-type F-box protein that may be involved in plant stress signaling by influencing the expression of PmADH1; thus, modulating the production of green leaf volatiles.

MR219 transgenic rice line which overexpressed an auxin-binding protein (ABP57) and its wild-type cultivar, MR219, were screened under well-watered (WW) and drought stress (DS) conditions at the early reproductive stage. This study was conducted with the standard planting distance and under a normal environment to assess the yield advantages based on the field conditions. The aim of this study was to understand the response of these rice genotypes towards DS at morpho-physiological, biochemical, and agronomical levels. It was found that the DS had affected all these levels of the genotypes studied; however, the transgenic plant showed a higher number of tillers, flag leaf area, biomass, relative water content, total chlorophyll content, and antioxidative defense mechanism than the MR219 under DS. Compared to its wild-type, the transgenic plant showed an increased leaf photosynthetic rate by 7% under WW and 11% under DS. The transgenic plant also showed higher yields than MR219 under the WW (10%) and DS (59%). The results propose that drought tolerance is significantly improved in the MR219 transgenic rice line. It may develop a new opportunity for the drought-tolerant rice breeding programme via overexpression of ABP57.

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