Nutrition utilization of entomopathogenic nematode Steinernema sp. SY-5 on recombinant crystalline inclusion proteins

Abstract:

[Objective] Phase I cells of Photorhabdus luminescens bacteria, symbiotically associated with entomopathogenic Heterorhabditis nematode, produce two types of intracellular crystalline inclusions, CipA and CipB, to support the symbiont. This study aimed to investigate the possible influence of Cip proteins on non-symbiotic Steinernema nematode. [Methods] Based on constructed Escherichia coli expression system of Cip proteins, co-culture system of recombinant E. coli bacteria and Steinernema sp. SY-5 nematode was set up. [Results] The Cip proteins significantly promoted the development of SY-5 nematode to make high adult rate of 65%?82%, gravid rate of 80%?95%, 30?50 eggs per nematode, and low mortalities. [Conclusion] As the nutrient reserves for Heterorhabditis nematode, Cip proteins can be accepted and utilized by Steinernema nematode. The progress on these proteins will provide insights into the mechanisms governing bacteria-nematode symbiosis.