1 Department of Plant Pathology, 1991 Upper Buford Circle, University of Minnesota, St. Paul, MN 55108.
2 Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132; and.
Phytopathology. 2019 Mar;109(3):402-408. doi: 10.1094/PHYTO-09-18-0331-R. Epub 2019 Feb 7.
Plant defensins are small, cysteine-rich antimicrobial peptides. These peptides have previously been shown to primarily inhibit the growth of fungal plant pathogens. Plant defensins have a γ-core motif, defined as GXCXC, which is required for their antifungal activity. To evaluate plant defensins as a potential control for a problematic agricultural disease (alfalfa crown rot), short, chemically synthesized peptides containing γ-core motif sequences were screened for activity against numerous crown rot pathogens. These peptides showed both antifungal and, surprisingly, antibacterial activity. Core motif peptides from Medicago truncatula defensins (MtDef4 and MtDef5) displayed high activity against both plant and human bacterial pathogens in vitro. Full-length defensins had higher antimicrobial activity compared with the peptides containing their predictive γ-core motifs. These results show the future promise for controlling a wide array of economically important fungal and bacterial plant pathogens through the transgenic expression of a plant defensin. They also suggest that plant defensins may be an untapped reservoir for development of therapeutic compounds for combating human and animal pathogens.
植物防御素是小的、富含半胱氨酸的抗菌肽。这些肽先前已被证明主要抑制真菌植物病原体的生长。植物防御素有一个γ-核心基序，定义为 GXCXC，这是其抗真菌活性所必需的。为了评估植物防御素作为一种潜在的控制农业问题（紫花苜蓿冠腐病）的方法，含有γ-核心基序序列的短化学合成肽被筛选以对抗多种冠腐病病原体的活性。这些肽显示出抗真菌活性，而且令人惊讶的是，还显示出抗细菌活性。来自紫花苜蓿防御素（MtDef4 和 MtDef5）的核心基序肽对植物和人类细菌病原体都显示出很高的体外活性。全长防御素比含有预测γ-核心基序的肽具有更高的抗菌活性。这些结果表明，通过转基因表达植物防御素，可以控制广泛的经济重要真菌和细菌植物病原体。它们还表明，植物防御素可能是开发治疗人类和动物病原体的化合物的未开发资源。
