Stenotrophomonas maltophilia as one of increasing food spoilage bacteria and fish pathogens has become a threat to aquiculture industry. A major factor contributing to the success of bacterium is its outstanding ability to secrete protease at low temperatures. Here, a cAMP receptor like protein (Clp) shows a positive regulation on this protease, named S. maltophilia temperature-response protease (SmtP). Interestingly, a two-component system, comprising of LotS sensor and LotR regulator, for low-temperature response is also confirmed to modulate SmtP expression with similar effect to Clp. Evidence is presented that LotS/LotR modulates smtP (coding SmtP) expression via Clp: clp promoter activity was reduced significantly at low temperatures and protease activity was partially restored by Clp overexpressed in lotS or lotR deletion strain. Furthermore, as a Clp negative effector, the binding ability of c-di-GMP with Clp is not impacted by temperature. c-di-GMP level was increased in S. maltophilia growing at high temperature, but not exhibited significantly in lotR deleted strain, these indicate that LotR is required for temperature modulating c-di-GMP level, although the synthesis or degradation activity of c-di-GMP by LotR was not detected. These findings suggest that LotS/LotR/Clp play an important role in responding to temperature stimuli via c-di-GMP mediated manner.

嗜麦芽窄食单胞菌是不断增加的食物变质细菌和鱼类病原体之一，已成为对水产养殖业的威胁。促成细菌成功的主要因素是其在低温下分泌蛋白酶的出色能力。在这里，cAMP受体样蛋白（Clp）对这种蛋白酶表现出正调节作用，这种蛋白称为嗜麦芽孢杆菌温度响应蛋白酶（SmtP）。有趣的是，还证实了由LotS传感器和LotR调节剂组成的用于低温响应的两组​​分系统可调节SmtP表达，其作用与Clp相似。证据呈现该地段/魔戒调制SMTP（编码SMTP）通过CLP表达：CLP在低温下启动子活性显着降低，并且通过在lotS或lotR缺失菌株中过表达的Clp部分恢复了蛋白酶活性。此外，作为Clp负效应子，c-di-GMP与Clp的结合能力不受温度的影响。c-di-GMP水平在高温下生长的嗜麦芽孢杆菌中有所增加，但在lotR缺失菌株中并未显着显示，这表明LotR是温度调节c-di-GMP水平所需的，尽管c的合成或降解活性未检测到LotR的-di-GMP。这些发现表明，LotS / LotR / Clp通过c-di-GMP介导的方式在响应温度刺激中起重要作用。