Elevated expression of ribosome-inactivating protein (RIP) genes in potyvirus-resistant watermelon in response to viral infection

Authors: Chanda, Bidisha; WU, SHAN - Boyce Thompson Institute; FEI, ZHANGJUN - Boyce Thompson Institute; Ling, Kai-Shu; Levi, Amnon

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2021
Publication Date: 1/20/2022
Citation: Chanda, B., Wu, S., Fei, Z., Ling, K., Levi, A. 2022. Elevated expression of ribosome-inactivating protein (RIP) genes in potyvirus-resistant watermelon in response to viral infection. Canadian Journal of Plant Pathology. 44(4):615-625. https://doi.org/10.1080/07060661.2021.2021450.
DOI: https://doi.org/10.1080/07060661.2021.2021450

Interpretive Summary: Watermelon, originating in Africa, is an important vegetable fruit crop widely grown in the U.S. and around the world. Besides the water content, watermelon is considered to be a rich source of vitamins, antioxidants and amino acids. One of major limiting factors in watermelon crop production is viral diseases. Several aphid-borne potyviruses, including papaya ringspot virus (PRSV) and zucchini yellow mosaic virus (ZYMV), have caused serious economic losses to watermelon production. Previously, we determined that a translation elongation factor (eIF4E) is responsible in conferring watermelon with resistance to ZYMV. Other studies have shown that ribosome-inactivating proteins (RIPs) have anti-microbial, antiviral and insecticidal properties. Watermelon and other cucurbits have been shown to contain a high level of RIPs. In the present study, we were interested in evaluating RIP expression in association with PRSV infection on watermelon. Interestingly, a higher level of RIP expression was associated with PRSV resistant watermelon plants. This finding may offer us an additional bio-marker in identifying watermelon with broad spectrum disease resistance.

Technical Abstract: Ribosome-inactivating proteins (RIPs) are widely known for their antiviral activity. We report RIPs from watermelon Citrullus lanatus subsp. vulgaris cv. Charleston Gray to be associated with resistance to Papaya ringspot virus watermelon strain (PRSV-W). PRSV-W, a potyvirus, causes infection to all types of cucurbits resulting in severe economic losses, similar to that of a related strain on papaya (PRSV-P) that has devastated the papaya industry worldwide. In our previous studies, we determined that a single nucleotide polymorphism in the watermelon eIF4E is likely responsible for recessive resistance in watermelon against a potyvirus, zucchini yellow mosaic virus (ZYMV). In the present study, using watermelon cultivars with distinct phenotype of resistance and susceptibility to PRSV-W infection and comparative measurement of expression of RIPs in watermelon throughout a disease progression process, we identified an enhanced expression of RIPs in PRSV-resistant watermelon upon PRSV-W infection.