Host Plant Resistance to Important Viruses in Cucurbits- Current Challenges and Advances

Cucurbit crops like cucumber, melon, squash, and watermelon are vital vegetables grown globally. Their production is under serious threat by viral diseases caused by a wide array of plant viruses including Cucumber mosaic virus (CMV), Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), and Papaya ringspot virus (PRSV). They cause severe yield losses and reduced fruit quality, forming a significant challenge for sustainable cucurbit production. Host plant resistance (HPR) provides a viable, environmentally friendly, and economically sound approach for controlling viral diseases in cucurbits. The present review presents an overview of the status of host resistance to major cucurbit-infecting viruses, including the origin of natural resistance, the pattern of inheritance, and the progress of breeding strategies. Conventional breeding, marker-assisted selection (MAS), transgenic methodology, and genome editing tools have all played roles in generating virus-resistant varieties. Nonetheless, the speedy development of viral strains, collapse of resistance, and narrow genetic diversity in certain cucurbit crops are still challenges. Combining genomic resources, high-density phenotyping, and bioinformatics is enabling the discovery and deployment of enduring resistance genes. In addition, utilization of wild relatives and landraces as a source of resistance is receiving increased interest. This review highlights the importance of interdisciplinarity to engineer broad-spectrum and lasting resistance. Host plant resistance will be critical for food security and decreasing the dependency on chemical controls in cucurbit production systems.