Temporal interactions of plant - insect - predator after infection of bacterial pathogen on rice plant

Authors: ZE, SUN - Huazhong Agricultural University; ZHUANG, LIU - Huazhong Agricultural University; WEN, ZHOU - Huazhong Agricultural University; HUANAN, JIN - Huazhong Agricultural University; HAO, LIU - Huazhong Agricultural University; AIMING, ZHOU - Huazhong Agricultural University; Zhang, Aijun; MAN-QUN, WANG - Huazhong Agricultural University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2016
Publication Date: 5/17/2016
Citation: Ze, S., Zhuang, L., Wen, Z., Huanan, J., Hao, L., Aiming, Z., Zhang, A., Man-Qun, W. 2016. Temporal interactions of plant - insect - predator after infection of bacterial pathogen on rice plant. Scientific Reports. 6:26043.

Interpretive Summary: The brown plant hopper (BPH) is among the most detrimental insect pests of rice, affecting plants at all stages of growth. Although some natural enemies play important roles in suppressing the BPH population via predation, the yield loss in susceptible rice cultivars attacked by BPH could still be up to 60%. In addition, certain pathogenic bacteria can cause serious diseases in rice plants, further reducing the rice yield. Research of basic aspects of interactions among plant – insect – predator – bacteria pathogenic infection in rice plants that may lead to novel or improved management tactics is warranted. In collaborative research, such interactions were investigated under laboratory conditions. Based on GC-MS analysis, we found that the volatile organic compounds (VOCs) emitted from the rice plants at various stages were significantly different. Theses VOCs may be the key factors to affect the behaviors of BPH and predators through the chemical communications among the host plants, pests, and natural enemies. These results provided insight into the interactions among plants, microbes, and insects which will help growers and scientists to better understand the mechanism of plant resistance to pests and diseases and, therefore, develop more sustainable strategies to effectively manage the rice insect pests using the natural VOCs and natural enemies, subsequently reducing the synthetic pesticide usage and increasing the crop yields.

Technical Abstract: Pathogenic infection on plants may affect interactions of the host-plants with their herbivores, as well as the herbivores with their predators. In this study, the effects of infection by pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), which causes a vascular disease in rice, in rice plants and consequent interactions with a rice herbivore, brown rice plant hopper (BPH), Nilaparvata lugens, and its major predator, Cyrtorhinus lividipennis, were investigated. The feeding behavior and developing performance analyses of BPH indicated that the rice plants exhibited increased resistance to BPH only at 3 d post-inoculation of Xoo, while the Xoo infection did not affect the development and fecundity of BPH. However, the preference analyses of BPH and its predator to rice plants indicated that BPH exhibited a higher preference to Xoo infected rice plants, whereas C. lividipennis preferred both BPH infected and uninfected rice plants equally. Further research was focused on the volatile organic compounds (VOCs) involved in different rice plants. GC-MS analysis of VOCs revealed that the herbivore-induced plant volatiles (HIPVs) emitted from BPH infected rice were significantly higher than those from healthy rice plants. In addition, Xoo infection on BPH fed plants caused rice plants to emit more HIPVs on the temporal dimension. Among HIPVs, a-pinene and green leaf volatiles from both Xoo and BPH infested rice plants were significantly higher than those from rice plants only infected by Xoo. These results demonstrated that Xoo infection significantly influenced the interactions of the rice plant with two non-vectors, BPH and its predator, although these effects exhibited in a temporal pattern after infection. On the other hand, neither the development/reproduction of BPH nor plant preference of BPH predator was affected.