First report of Apple of Peru (Nicandra physalodes) infected with pepper mottle virus in Hawai'i

Authors: WANG, D. - China Medical University; HAMIN, ISLAM - University Of Hawaii; BORTH, WAYNE - University Of Hawaii; MELZER, MICHAEL - University Of Hawaii; Suzuki, Jon; Wall, Marisa; Matsumoto Brower, Tracie; SUN, G - China Medical University; HU, JOHN - University Of Hawaii

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2018
Publication Date: 11/2/2018
Citation: Wang, D., Hamin, I., Borth, W.B., Melzer, M.J., Suzuki, J.Y., Wall, M.M., Matsumoto Brower, T.K., Sun, G.F., Hu, J.S. 2018. First report of Apple of Peru (Nicandra physalodes) infected with pepper mottle virus in Hawai'i. Plant Disease. 103(1):169. https://doi.org/10.1094/PDIS-06-18-1061-PDN.
DOI: https://doi.org/10.1094/PDIS-06-18-1061-PDN

Interpretive Summary: In 2018, apple of Peru plants (Nicandra physalodes (L.) with severe virus-like symptoms including mosaic, mottling and crinkling of leaves were found at one location on the island of Oahu, Hawaii, U.S.A. DNA and antibody-based diagnostic tests revealed that diseased plants were infected with Pepper mottle virus (PepMoV), a potyvirus that causes economic losses to peppers and tomatoes in Honduras, South Korea and Hawaii 2012. Apple of Peru is a plant that is tolerant to commonly used herbicides and where it occurs is a serious, competing weed in crop fields, including tomato and pepper fields in Hawaii. It is a member of the nightshade family and along with other weeds in this family is known as an alternative host of several viruses. This first report of apple of Peru as a host for Pepper mottle virus in Hawaii indicates that eliminating weeds of the nightshade family is an important management step to mitigate potential commercial crop losses by this virus.

Technical Abstract: In 2018, apple of Peru plants (Nicandra physalodes (L.) with severe virus-like symptoms including mosaic, mottling and crinkling of leaves were found in Honolulu, near the University of Hawaii at Manoa on the island of Oahu, Hawaii, U.S.A. Samples tested positive following Potyvirus-specific RT-PCR and ELISA indicating potyviral infection. A 328 bp amplicon corresponding to the nuclear inclusion body (NIb) region of the potyviral genome was generated by RT-PCR of RNA from infected plants using universal, potyvirus-specific primers. The sequence of the NIb region from the viral samples obtained from apple of Peru plants indicated a 95% nucleotide identity with the corresponding sequence from a Pepper mottle virus (PepMoV) isolate from Florida, whereas a smaller, 310 segment representing the NIb sequence alone exhibited 97% identity with the respective sequence from the Florida isolate. A 910 bp PCR amplicon representing the PepMoV coat protein sequence obtained by RT-PCR of infected apple of Peru samples exhibited 98% nucleotide identity with a PepMoV isolate from Hawaii found in tomato. In addition, all of the symptomatic apple of Peru plants tested positive for PepMoV by triple-antibody sandwich (TAS) ELISA using PepMoV-specific antibodies. Pepper mottle virus (PepMoV), in the genus Potyvirus (family Potyviridae) is a monopartite, positive sensed, single-stranded RNA virus that causes economic losses to peppers and tomatoes in Honduras, South Korea and Hawaii. Apple of Peru (Nicandra physalodes (L.) is a member of the Solanaceae family, is tolerant to commonly used herbicides, and competes with and is a serious weed in cultivated crops. Additionally, apple of Peru and other solanaceaeous weeds are known as alternative hosts of several viruses. This study is the first report of apple of Peru as a host of PepMoV in Hawaii. This finding indicates that eliminating solanaceous weeds is an important management step to mitigate potential losses by PepMoV in the relevant commercial crops.