Swathi Anuradha T, Divya K, Jami S K, Kirti P B
Department of Plant Sciences, University of Hyderabad, Hyderabad, India.
Plant Cell Rep. 2008 Nov;27(11):1777-86. doi: 10.1007/s00299-008-0596-8. Epub 2008 Aug 29.
Defensins are small positively charged, antimicrobial peptides (approximately 5 kDa in size) and some of them exhibit potent antifungal activity. We have cloned the complete cDNA containing an ORF of 243 bp of a defensin of mustard. The deduced amino acid sequence of the peptide showed more than 90% identity to the amino acid sequence of the well-characterized defensins, RsAFP-1 and RsAFP-2 of Raphanus sativus. We have generated and characterized transgenic tobacco and peanut plants constitutively expressing the mustard defensin. Transgenic tobacco plants were resistant to the fungal pathogens, Fusarium moniliforme and Phytophthora parasitica pv. nicotianae. Transgenic peanut plants showed enhanced resistance against the pathogens, Pheaoisariopsis personata and Cercospora arachidicola, which jointly cause serious late leaf spot disease. These observations indicate that the mustard defensin gene can be deployed for deriving fungal disease resistance in transgenic crops.
防御素是一类带正电荷的小抗菌肽（大小约为5千道尔顿），其中一些具有强大的抗真菌活性。我们克隆了包含芥菜防御素243个碱基对开放阅读框的完整cDNA。该肽推导的氨基酸序列与已充分表征的萝卜RsAFP - 1和RsAFP - 2防御素的氨基酸序列有90%以上的同一性。我们构建并鉴定了组成型表达芥菜防御素的转基因烟草和花生植株。转基因烟草植株对真菌病原体串珠镰刀菌和烟草疫霉具有抗性。转基因花生植株对共同引起严重叶斑病的花生叶点霉和花生尾孢菌病原体表现出增强的抗性。这些观察结果表明，芥菜防御素基因可用于培育转基因作物的真菌病害抗性。
