Transgenic tobacco and peanut plants expressing a mustard defensin show resistance to fungal pathogens

Abstract

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.

Insect antimicrobial peptides and their applications

“…Plant defensins have been expressed in transgenic rice (Choi et al, 2009; Jha and Chattoo, 2010), wheat (Li et al, 2011), banana (Ghag et al, 2012), tomato (Abdallah et al, 2010; Portieles et al, 2010), “Egusi” melon (Ntui et al, 2010), peanut (Swathi Anuradha et al, 2008), tobacco (Portieles et al, 2010; Swathi Anuradha et al, 2008), and Arabidopsis (Kaur et al, 2012). Transgenic expression of an insect defensin ( G. mellonella gallerimycin) and cecropin (sarcotoxin-IA) in tobacco also confers resistance to pathogenic fungi (Mitsuhara et al, 2000; Ohshima et al, 1999).…”

Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1

“…Gao et al (2000) reported that transgenic potatoes expressing the alfAFP had significant resistance to V. dahliae infection in the greenhouse and the field. Recently, there have been several other reports of class-I plant defensins enhancing fungal resistance in transgenic plants, including papaya (Zhu et al , 2007), rice (Kanzaki et al , 2002; Jha and Chattoo, 2009), potato (Portieles et al , 2010), peanut (Anuradha et al , 2008), wheat (Li et al , 2011), banana (Ghag et al , 2012), and Arabidopsis (Kaur et al , 2012). In addition, Dracatos et al (2014) has demonstrated that foliar applications of NaD1 protect oat plants from infection by the crown rust, Puccinia coronata .…”

Impact of Molecular Genetic Research on Peanut Cultivar Development

“…Transgenic peanut expressing a human Bcl-xL gene has improved tolerance to paraquat, a bipyridilium herbicide [76]. Fungal resistance in peanut was enhanced by transforming several genes including barley oxlate oxidase [77,78], mustard defensin [60], rice chitinase [79,80] and chloroperoxidase [81]. Evaluation of some transgenic lines was advanced to field studies such as resistance to Sclerotinia minor, which was confirmed in oxlate oxidase and rice chitinase transformed lines [78,79].…”

“…Various peanut tissues including leaf sections, cotyledonary nodes, longitudinal cotyledon halves, embryo axes, embryo leaflets, and hypocotyls have been tested for A. tumefaciens transformation [58][59][60]. Apical or axillary meristematic cells in these tissues allow for multiple shoot regeneration and have been targeted for gene transfer by A. tumefaciens.…”