Gao Saisai, Han Hongjia, Yang Fan, Liu Xinyang, Liang Wenxing, Liu Mengjie
Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China.
College of Life Sciences, Shandong Normal University, Jinan, China.
Front Microbiol. 2025 Aug 7;16:1639396. doi: 10.3389/fmicb.2025.1639396. eCollection 2025.
Biological control agents (BCAs) offer an environmentally friendly alternative to chemical pesticides for plant disease management. However, the efficacy of live microbial BCAs is often compromised by ecological constraints. Cell-free supernatants (CFSs), derived from BCA fermentation, contain most active biocontrol compounds responsible for disease suppression and can be directly applied without introducing living organisms into the environment. Our prior work demonstrated that CFS from QSE-21 (CFS-Q) directly inhibits the growth and development of . This study investigates CFS-Q-induced systemic resistance in tomato plants and fruits against .
Tomato seedlings were foliar-sprayed with CFS-Q or controls. Systemic resistance was assessed by challenging distal leaves with . Comparative transcriptomics analyzed gene expression (RNA sequencing) in treated vs. untreated plants, with/without pathogen inoculation. Tomato fruits were sprayed with CFS-Q, live QSE-21 cells (Cell-Q), or LB medium (control group), followed by inoculation.
Application of CFS-Q triggered immune responses in tomato seedlings, conferring enhanced local and systemic resistance against without direct pathogen contact. Comparative transcriptomics revealed that CFS-Q treatment activated multiple immune signaling pathways in tomato, regardless of inoculation. This immune priming effect translated into significantly faster and stronger defensive reactions against attack. Crucially, compared to spraying live QSE-21 cells, spraying CFS-Q exhibited superior efficacy in controlling on tomato fruits.
CFS-Q operates via a dual mechanism: direct antagonism (established previously) and induced systemic resistance (ISR), evidenced by immune pathway activation. The priming effect ensures rapid defense mobil.
生物防治剂（BCAs）为植物病害管理提供了一种环保的化学农药替代品。然而，活的微生物生物防治剂的功效常常受到生态限制的影响。源自生物防治剂发酵的无细胞上清液（CFSs）含有负责病害抑制的大多数活性生物防治化合物，并且可以直接施用而无需将活生物体引入环境。我们之前的工作表明，来自QSE - 21的CFS（CFS - Q）直接抑制……的生长和发育。本研究调查了CFS - Q诱导番茄植株和果实对……的系统抗性。
用CFS - Q或对照对番茄幼苗进行叶面喷雾。通过用……挑战远端叶片来评估系统抗性。比较转录组学分析了经处理与未处理的植物在接种/未接种病原体情况下的基因表达（RNA测序）。用CFS - Q、活的QSE - 21细胞（Cell - Q）或LB培养基（对照组）对番茄果实进行喷雾，随后进行……接种。
施用CFS - Q引发了番茄幼苗中的免疫反应，在未直接接触病原体的情况下赋予了增强的局部和系统抗性以抵抗……。比较转录组学显示，无论是否接种……，CFS - Q处理均激活了番茄中的多种免疫信号通路。这种免疫引发效应转化为对……攻击的显著更快且更强的防御反应。至关重要的是，与喷雾活的QSE - 21细胞相比，喷雾CFS - Q在控制番茄果实上的……方面表现出更高的功效。
CFS - Q通过双重机制起作用：直接拮抗作用（先前已确定）和诱导系统抗性（ISR），这通过免疫途径激活得到证明。引发效应确保了快速的防御动员。
