Nematicidal Activity of Cry1Ea11 from Bacillus thuringiensis BRC-XQ12 Against the Pine Wood Nematode (Bursaphelenchus xylophilus)

作者：Huang, Tianpei; Lin, Qunxin; Qian, Xiaoli; Zheng, Ying; Yao, Junmin; Wu, Huachuan; Li, Mengmeng; Jin, Xin; Pan, Xiaohong; Zhang, Lingling; Guan, Xiong^*

来源：Phytopathology, 2018, 108(1): 44-51.

DOI：10.1094/PHYTO-05-17-0179-R

• CRYSTAL PROTEIN GENES
• ROOT-KNOT NEMATODE
• INSECT VECTOR
• CRY GENE
• IDENTIFICATION
• RESISTANCE
• EXPRESSION
• STRAINS
• REDUCTION
• TOXICITY

The nematicidal activity of 92 Bacillus thuringiensis strains against the pine wood nematode Bursaphelenchus xylophilus, one of the world's top 10 plant-parasitic nematodes, was determined. The insecticidal crystal proteins (ICPs) from Bacillus thuringiensis BRC-XQ12 were the most toxic to Bursaphelenchus xylophilus, with a lethal concentration 50 (LC50) of 32.13 mu g/ ml. Because the ICPs expressed by Bacillus thuringiensis BRC-XQ12 were closest to Cry1Ea6 and B. thuringiensis BRC-XQ12 contained four kinds of cry1 subgenes (cry1Aa, cry1Cb, cry1Ea, and cry1Ia), Cry1Ea was most likely to be the key active component against the nematode. The 3,516-bp cry1Ea11 gene from BRC-XQ12, as designated by the B. thuringiensis delta-endotoxin nomenclature committee, was expressed in Escherichia coli. Purified Cry1Ea11 showed an LC50 of 32.53 and 23.23 mu g/ ml at 24 and 48 h, with corresponding virulence equations of Y = 32.15X + 1.38 (R-2 = 0.9951) and Y = 34.29X + 3.16 (R-2 = 0.9792), respectively. In order to detect the pathway of B. thuringiensis Cry1Ea11 into Bursaphelenchus xylophilus, the nematode was fed with NHS-rhodamine-labeled GST-Cry1Ea11. The results of confocal laser-scanning microscopy showed that the 159-kDa GST-Cry1Ea11 could be detected in the stylet and the esophageal lumen of the pine wood nematode, indicating that GST-Cry1Ea11 could enter into the nematode through the stylet. As far as we know, no Cry1 proteins have been shown to have activity against plant-parasitic nematodes before. These results demonstrate that Cry1Ea11 is a promising nematicidal protein for controlling pine wilt disease rendered by B. xylophilus, further dramatically broadening the spectrum of Bacillus thuringiensis ICPs.

• 出版日期2018-1
• 单位福建农林大学