Trotel-Aziz Patricia, Abou-Mansour Eliane, Courteaux Barbara, Rabenoelina Fanja, Clément Christophe, Fontaine Florence, Aziz Aziz
Research Unit EA 4707 RIBP, SFR Condorcet FR CNRS 3417, University of Reims Champagne-Ardenne, Reims, France.
Department of Plant Biology, University of Fribourg, Fribourg, Switzerland.
Front Plant Sci. 2019 Jan 24;10:25. doi: 10.3389/fpls.2019.00025. eCollection 2019.
Plant pathogens have evolved various strategies to enter hosts and cause diseases. Particularly , a member of Botryosphaeria dieback consortium, can secrete the phytotoxins (-)-terremutin and ()-mellein during grapevine colonization. The contribution of phytotoxins to Botryosphaeria dieback symptoms still remains unknown. Moreover, there are currently no efficient control strategies of this disease, and agro-environmental concerns have raised increasing interest in biocontrol strategies to limit disease spread in vineyards, especially by using some promising beneficial bacteria. Here, we first examined the biocontrol capacity of PTA-271 against -Bt67 strain producing both (-)-terremutin and ()-mellein. We then focused on the direct effects of PTA-271 on pathogen growth and the fate of pure phytotoxins, and explored the capacity of PTA-271 to induce or prime grapevine immunity upon pathogen infection or phytotoxin exposure. Results provided evidence that PTA-271 significantly protects grapevine cuttings against and significantly primes the expression of (encoding a β-1,3-glucanase) and (9--epoxycarotenoid dioxygenase involved in abscisic acid biosynthesis) genes upon pathogen challenge. Using plantlets, we also showed that PTA-271 triggers the expression of salicylic acid- and jasmonic acid-responsive genes, including (encoding a glutathione--transferase) involved in detoxification process. However, in PTA-271-pretreated plantlets, exogenous (-)-terremutin strongly lowered the expression of most of upregulated genes, except . Data also indicated that PTA-271 can detoxify both (-)-terremutin and ()-mellein and antagonize under conditions. Our findings highlight (-)-terremutin and ()-mellein as key aggressive molecules produced by that may weaken grapevine immunity to promote Botryosphaeria dieback symptoms. However, PTA-271 can efficiently attenuate Botryosphaeria dieback by enhancing some host immune responses and detoxifying both phytotoxins produced by .
植物病原体已经进化出各种策略来侵入宿主并引发疾病。特别是，葡萄座腔菌溃疡病菌群的一个成员，在侵染葡萄藤的过程中能够分泌植物毒素（-）-土曲霉毒素和（）-蜜色菌素。植物毒素对葡萄座腔菌溃疡病症状的影响仍然未知。此外，目前尚无针对这种疾病的有效防治策略，并且农业环境问题引发了人们对生物防治策略的日益关注，以限制该疾病在葡萄园中的传播，特别是通过使用一些有前景的有益细菌。在此，我们首先检测了PTA - 271对产生（-）-土曲霉毒素和（）-蜜色菌素的Bt67菌株的生物防治能力。然后，我们重点研究了PTA - 271对病原体生长和纯植物毒素命运的直接影响，并探索了PTA - 271在病原体感染或植物毒素暴露时诱导或增强葡萄藤免疫的能力。结果表明，PTA - 271能显著保护葡萄插条免受侵害，并在病原体攻击时显著增强（编码β - 1,3 - 葡聚糖酶）和（参与脱落酸生物合成的9 - 顺式环氧类胡萝卜素双加氧酶）基因的表达。使用组培苗，我们还表明PTA - 271能触发水杨酸和茉莉酸响应基因的表达，包括参与解毒过程的（编码谷胱甘肽 - S - 转移酶）。然而，在经PTA - 271预处理的组培苗中，外源（-）-土曲霉毒素强烈降低了除之外的大多数上调基因的表达。数据还表明，PTA - 271可以使（-）-土曲霉毒素和（）-蜜色菌素解毒，并在条件下拮抗。我们的研究结果突出了（-）-土曲霉毒素和（）-蜜色菌素是由产生的关键侵袭性分子，它们可能会削弱葡萄藤的免疫力，从而促进葡萄座腔菌溃疡病症状的出现。然而，PTA - 271可以通过增强一些宿主免疫反应和使产生的两种植物毒素解毒，有效地减轻葡萄座腔菌溃疡病。
