Submitted to: Journal of Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2017
Publication Date: 1/19/2017
Citation: Medrano, E.G., Bell, A.A. 2017. An opportunistic Pantoea sp. isolated from a cotton fleahopper that is capable of causing cotton (Gossypium hirsutum L.) bud rot. Journal of Agricultural Sciences. 8:64-76.
Interpretive Summary: The bacterium Pantoea ananatis is capable of inhabiting a broad spectrum of environments from soil to infective representatives that attack humans and plants. Our research efforts include detecting and understanding vector-borne diseases of cotton. Here, we report the identification of P. ananatis strains as a main culprit of damage resulting from cotton fleahopper feeding on flower buds causing disease. Fleahoppers feed via a piercing-sucking mechanism, and are considered a significant pest of early cotton fruiting structures. We found that puncture inoculation of P. ananatis (simulated fleahopper feeding) alone mimics fleahopper associated bud damage and results in disease development. This work showed that strains of P. ananatis can be cotton pathogens and thus further illustrated the versatility of this bacterial species. Generally, this research establishes a critical factor involved in cotton fleahopper associated cotton yield losses which should be a consideration in research focused on controlling losses to this pest.
Technical Abstract: Pantoea ananatis (Serano) representatives are known to have a broad host range including both humans and plants. The cotton fleahopper (Pseudatomoscelis seriatus, Reuter) is a significant pest that causes cotton bud damage that may result in significant yield losses. In this study, cotton fleahoppers collected from the field were raised on green beans in the laboratory. Adult insects were then caged with greenhouse grown cotton buds. Buds that abscised following feeding by the insect consistently showed necrosis of the ovary including the wall. A collection of bacterial isolates from both laboratory-reared insects and diseased buds were analyzed using carbon utilization and enzyme production tests, fatty acid methyl ester profile analysis, and by cloning and sequencing 16S RNA genes. Results showed that a majority of the isolates were best classified as P. ananatis. Upon simulated fleahopper feeding (i.e., penetrative inoculation), a fleahopper isolate rotted cotton buds. Additionally, fleahoppers were fed beans contaminated with rifampicin-resistant variants of either a putative P. ananatis fleahopper isolate or a P. agglomerans strain known to be transmitted by the southern green stink bug, Nezara viridula (L.). The putative P. ananatis was both acquired and transmitted by the fleahoppers whereas, P. agglomerans was only acquired. These results indicated the fleahoppers are vectors of opportunistic P. ananatis strains causing loss of the cotton fruiting structures.