Controlling sap-sucking insect pests with recombinant endophytes expressing plant lectin

Xiuyun Zhao,Xinrong Ma,Nan Lan,Xianfang Zhang,Gaofu Qi

doi:10.1038/npre.2010.4862.1

Xiuyun Zhao, Xinrong Ma + Show 3 more

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https://doi.org/10.1038/npre.2010.4862.1

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Abstract

AbstractWe developed a novel pest management strategy, which uses endophytes to express anti-pest plant lectins. Fungal endophyte of Chaetomium globosum YY-11 with anti-fungi activities was isolated from rape seedlings, and bacterial endophytes of SJ-10 (Enterobacter sp.) and WB (Bacillus subtilis) were isolated from rice seedlings. Pinellia ternate agglutinin gene was cloned into SJ-10 and WB for expression by a shuttle vector, and YY-11 was mediated by Agrobacterium tumefaciens. Positive transformants were evaluated using PCR and Western blot assay. Recombinant endophytes colonized most of crops, and resistance of rice seedlings, which were inoculated with the recombinant endophytic bacteria, to white backed planthoppers was dramatically enhanced by decreasing the survival and fecundity of white backed planthoppers. Rape inoculated with recombinant endophytic fungi significantly inhibited the growth and reproduction of aphids. Recombinant endophytes expressing PTA may endow hosts with resistance against sap-sucking pests.

Highlights

Several transgenic crops such as transgenic cotton and rice expressing Bt toxin have already been planted in several countries to control Lepidopterous pests
Downing et al transferred cry1Ac7 gene of Bacillus thuringiensis strain 234 into the endophytic bacterium Herbaspirillum seropedicae which was found in sugarcane for controlling the sugarcane borer Eldana saccharina, and showed this genetically modified endophyte could inhibit the growth of the sugarcane borer larvae to some degree[11]
The total soluble proteins in the transformants were analyzed by SDS-PAGE, which showed that PTA was successfully expressed by rYY-11 with the same molecular weight as native PTA protein extracted from P. ternate corm (Fig 2B)

Summary

Introduction

Several transgenic crops such as transgenic cotton and rice expressing Bt toxin have already been planted in several countries to control Lepidopterous pests. Sap-sucking insect pests (e.g., red spiders, cotton plant bugs, and planthopper) are becoming the main threats to agricultural industries with the increasing plantation of transgenic crops expressing Bt toxin[3,4]. Insect bioassays showed that transgenic plants expressing PTA significantly inhibited aphid growth and exhibited considerable insecticidal activities against rice brown planthopper. To our best knowledge, there are still no other insecticidal proteins, which are as adequately effective as plant lectins to control sap-sucking insects. Endophytic microorganisms are those that inhabit in the interiors of plants, especially in leaves, branches, and stems, without apparent harms to the hosts[8]. All of these endophytic microorganisms could colonize different types of crops such as rice, wheat, maize, cotton, and radish (unpublished data)

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