Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China.
Jiangsu Provincial Key Construction Laboratory of Special Biomass Resource Utilization, Nanjing Xiaozhuang University, Nanjing, 211171, China.
Sci Rep. 2019 Oct 25;9(1):15359. doi: 10.1038/s41598-019-51762-0.
The diverse antimicrobial properties of defensins have attracted wide scientific interest in recent years. Also, antimicrobial peptides (AMPs), including cecropins, histatins, defensins, and cathelicidins, have recently become an antimicrobial research hotspot for their broad-spectrum antibacterial and antifungal activities. In addition, defensins play important roles in plant growth, development, and physiological metabolism, and demonstrate tissue specificity and regulation in response to pathogen attack or abiotic stress. In this study, we performed molecular cloning, characterization, expression profiling, and functional analysis of a defensin from Populus trichocarpa. The PtDef protein was highly expressed in the prokaryotic Escherichia coli system as a fusion protein (TrxA-PtDef). The purified protein exhibited strong antibacterial and antifungal functions. We then applied PtDef to rooting culture medium as an alternative exogenous additive to cefotaxime. PtDef expression levels increased significantly following both biotic and abiotic treatment. The degree of leaf damage observed in wild-type (WT) and transgenic poplars indicates that transgenic poplars that overexpress the PtDef gene gain enhanced disease resistance to Septotis populiperda. To further study the salicylic acid (SA) and jasmonic acid (JA) signal transduction pathways, SA- and JA-related and pathogenesis-related genes were analyzed using quantitative reverse-transcription polymerase chain reaction; there were significant differences in these pathways between transgenic and WT poplars. The defensin from Populus trichocarpa showed significant activity of anti-bacteria and anti-fungi. According to the results of qRT-PCR and physiological relevant indicators, the applied PtDef to rooting culture medium was chosen as an alternative exogenous additive to cefotaxime. Overexpressing the PtDef gene in poplar improve the disease resistance to Septotis populiperda.
防御素的多种抗菌特性近年来引起了科学界的广泛关注。此外，抗菌肽（AMPs），包括 Cecropins、Histatins、防御素和 Cathelicidins，由于其广谱的抗菌和抗真菌活性，最近成为抗菌研究的热点。此外，防御素在植物的生长、发育和生理代谢中发挥着重要作用，并且在应对病原体攻击或非生物胁迫时表现出组织特异性和调节作用。在本研究中，我们对毛白杨中的防御素进行了分子克隆、特性描述、表达谱分析和功能分析。PtDef 蛋白在原核大肠杆菌系统中作为融合蛋白（TrxA-PtDef）高度表达。纯化后的蛋白表现出强烈的抗菌和抗真菌功能。然后，我们将 PtDef 应用于生根培养基中，作为头孢噻肟的替代外源添加剂。PtDef 的表达水平在生物和非生物处理后显著增加。野生型（WT）和转基因杨树叶片的损伤程度表明，过表达 PtDef 基因的转基因杨树对杨扇舟蛾获得了增强的抗病性。为了进一步研究水杨酸（SA）和茉莉酸（JA）信号转导途径，我们利用定量逆转录聚合酶链反应（qRT-PCR）分析了 SA 和 JA 相关及病程相关基因；在转基因和 WT 杨树之间，这些途径存在显著差异。毛白杨的防御素表现出显著的抗细菌和抗真菌活性。根据 qRT-PCR 的结果和生理相关指标，选择 PtDef 应用于生根培养基作为头孢噻肟的替代外源添加剂。在杨树中过表达 PtDef 基因可提高对杨扇舟蛾的抗病性。
