Interactions of insecticidal toxin gene products from Xenorhabdus nematophilus PMF1296
Interactions of insecticidal toxin gene products from Xenorhabdus nematophilus PMF1296
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DOI：
10.1128/aem.69.6.3344-3349.2003
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发表时间：
2003-06-01
影响因子：
4.4
通讯作者：
Morgan, JAW
中科院分区：
文献类型：
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作者：
Sergeant, M;Jarrett, P;Morgan, JAW
嗜线虫致病杆菌PMFI296基因组片段上的4个基因参与了对3种重要商业昆虫的杀虫活性。每个基因在大肠杆菌中单独和组合表达，并测定裂解产物的杀虫活性。这四个基因(xptA1、xpLA2、xptB1和xptC1)在大肠杆菌中表现出对菜青虫、菜青虫和菜青虫的活性。基因xptA1、xptB1和xptC1参与表达对菜青虫和菜青虫的活性，而基因xptA2、xptB1和xptC1参与表达对青枯病的活性。当这三个基因在大肠杆菌中单独表达，并将细胞裂解产物用于昆虫检测或混合使用时，可检测到很低的杀虫活性。如果在同一细胞中表达xptB1和xptC1基因，并将该细胞裂解物与表达xptA1的细胞混合，则菜青虫和白菜疫霉菌的活性得到恢复。同样，将XptB1/C1裂解物与XptA2裂解物混合后，恢复了对绿色隐翅虫的活性。线虫X.nematophilus PMFI296中的单个基因中断降低了对昆虫的活性；这种活性可以通过与表达xptA1或xptA2的细胞的各自中断或表达xptB1和xptC1的大肠杆菌的单个中断这两个基因的单独中断来互补来恢复。XptA2、xptC1和xptB1基因在pMFI296中以操纵子的形式表达，失活的xptA2或xptC1导致下游基因(S)沉默，而xptA1作为单基因表达。因此，这两个三个基因产物组合相互作用，产生良好的杀虫活性。
Four genes on a genomic fragment from Xenorhabdus nematophilus PMFI296 were shown to be involved in insecticidal activity towards three commercially important insect species. Each gene was expressed individually and in combinations in Escherichia coli, and the insecticidal activity of the lysates was determined. The combined four genes (xptA1, xpLA2, xptB1, and xptC1), in E. coli, showed activity towards Pieris brassicae, Pieris rapae, and Heliothis virescens. The genes xptA1, xptB1, and xptC1 were involved in expressing activity towards P. rapae and P. brassicae, while the genes xptA2, xptB1, and xptC1 were needed for activity towards H. virescens. When each of these three genes was expressed individually in E. coli and the cell lysates were used in insect assays or mixed and then used, insecticidal activity was detected at a very low level. If the genes xptB1 and xptC1 were expressed in the same E. coli cell and this cell lysate was mixed with cells expressing xptA1, activity was restored to P. rapae and P. brassicae. Similarly mixing XptB1/C1 lysate with XptA2 lysate restored activity towards H. virescens. Individual gene disruptions in X. nematophilus PMFI296 reduced activity to insects; this activity was restored by complementation with cells expressing either xptA1 or xptA2 for their respective disruptions or E. coli expressing both xptB1 and xptC1 for individual disruptions of either of these genes. The genes xptA2, xptC1, and xptB1 were expressed as an operon in PMFI296 and inactivation of xptA2 or xptC1 resulted in silencing of downstream gene(s), while xptA1 was expressed as a single gene. Therefore, the two three gene product combinations interact with each other to produce good insecticidal activity.