An ERF/AP2-type transcription factor (CaPF1) was isolated by differential-display reverse transcription-PCR, following inoculation of the soybean pustule pathogen Xanthomonas axonopodis pv glycines 8ra, which induces hypersensitive response in pepper (Capsicum annuum) leaves. CaPF1 mRNA was induced under conditions of biotic and abiotic stress. Higher levels of CaPF1 transcripts were observed in disease-resistant tissue compared with susceptible tissue. CaPF1 expression was additionally induced using various treatment regimes, including ethephon, methyl jasmonate, and cold stress. To determine the role of CaPF1 in plants, transgenic Arabidopsis and tobacco (Nicotiana tabacum) plants expressing higher levels of CaPF1 were generated. Gene expression analyses of transgenic Arabidopsis and tobacco revealed that the CaPF1 level in transgenic plants affects expression of genes that contain either a GCC or a CRT/DRE box in their promoter regions. Furthermore, transgenic Arabidopsis plants expressing CaPF1 displayed tolerance against freezing temperatures and enhanced resistance to Pseudomonas syringae pv tomato DC3000. Disease tolerance was additionally observed in CaPF1 transgenic tobacco plants. The results collectively indicate that CaPF1 is an ERF/AP2 transcription factor in hot pepper plants that may play dual roles in response to biotic and abiotic stress in plants.
SummaryThis study demonstrated that tomato Male sterile 10
35 encodes a basic helix–loop–helix transcription factor involved in meiosis and tapetum development at the early stage of anther development.
An extreme diversity of substrates and catalytic reactions of cytochrome P450 (P450) enzymes is considered to be the consequence of evolutionary adaptation driven by different metabolic or environmental demands. Here we report the presence of numerous natural variants of P450 BM3 (CYP102A1) within a species of Bacillus megaterium. Extensive amino acid substitutions (up to 5% of the total 1049 amino acid residues) were identified from the variants. Phylogenetic analyses suggest that this P450 gene evolve more rapidly than the rRNA gene locus. It was found that key catalytic residues in the substrate channel and active site are retained. Although there were no apparent variations in hydroxylation activity towards myristic acid (C14) and palmitic acid (C16), the hydroxylation rates of lauric acid (C12) by the variants varied in the range of >25-fold. Interestingly, catalytic activities of the variants are promiscuous towards non-natural substrates including human P450 substrates. It can be suggested that CYP102A1 variants can acquire new catalytic activities through site-specific mutations distal to the active site.
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