Gentian lipid transfer protein homolog with antimicrobial properties confers resistance to Botrytis cinerea in transgenic tobacco

Abstract

An antifungal protein fraction against Botrytis cinerea was purified from the leaves of Gentiana triflora. Polypeptides with molecular weight ca. 8.0 K (8.0 KP) and 7.0 K (7.0 KP) were detected by Tricine-SDS PAGE under reducing conditions. The deduced amino acid sequence of 8.0 KP cDNA showed amino acid identities with lipid transfer proteins from Apium graveolens (32.4%), Lycopersicon pennellii (31.5%), L. esculentum (31.5%), Nicotiana tabacum (30.7%), non-specific lipid transfer protein from L. esculentum (28.0%), and an unknown protein from Prosopis juliflora (30.7%) (GtLTP1). The deduced amino acid sequence of 7.0 KP showed amino acid identities with putative lipid transfer proteins from Arabidopsis thaliana (26.3% and 22.9%), Gossypium hirsutum (21.0%), Tamarix hispida (19.5%), Populus trichocarpa (15.9%) and an unknown protein from Vitis vinifera (17.2%) (GtLTP2). Both GtLTP1 and GtLTP2 were present as a multi-gene family in the genome and were strongly expressed in the roots and stems. Overexpression of GtLTP1 in tobacco plants improved tolerance against B. cinerea, demonstrating that GtLTP1 is a useful molecular tool for genetic engineering of disease-resistant plants.