Factors associated with variation in symptomatology induced by maize yellow mosaic virus (MaYMV) in maize crop

• Grant number: 24/07685-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Joao Roberto Spotti Lopes
• Grantee: Leonardo Coletti Spada
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 25/09230-6 - Factors associated with variation in symptomatology induced by maize yellow mosaic virus (MaYMV) in maize crop, BE.EP.IC

Abstract

The maize crop (Zea mays L.) stands out as one of the most important worldwide, with Brazil holding a significant position as one of the main producers and exporters. This scenario is possible due to various factors, with an emphasis on the practice of cultivating two or more maize crops in the same area or region during the year. However, combined with the presence of volunteer maize plants during the offseason, there is the phenomenon known as the "green bridge," which favors the maintenance of pests and pathogens in the field, with emphasis on vector insects that cause indirect damage through the transmission of phytopathogens. Among these, the corn leafhopper Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) and the corn aphid Rhopalosiphum maidis (Hemiptera: Aphididae) are becoming increasingly relevant. Regarding the corn aphid (R. maidis), a virus transmitted by this vector has stood out: the Maize Yellow Mosaic Virus (MaYMV, family Solemoviridae, genus Polerovirus). It was first diagnosed in Brazil in 2017, proving to be a virus of extreme relevance, with high potential impact on maize crops worldwide. Furthermore, classified as a poleovirus (genus Polerovirus), it is characterized by being phloem-restricted, where its symptoms and impacts are still not well understood. In Brazil, symptoms were reported as mild mosaic or asymptomatic infection, or in cases of mixed infections, a more severe mosaic with the presence of necrotic lesions. However, such reports differed from other studies conducted in China (provinces of Yunnan and Guizhou) and Africa, where MaYMV was associated, respectively, with symptoms of yellow mosaic and leaf reddening (also observed in Henan province, China). Thus, the present project aims to understand the factors involved in these symptomatic differences, evaluating the effect of different maize genotypes and the effect of MaYMV isolates. As a consequence, it will be possible to advance knowledge about the virus and its impacts, allowing the development of effective management strategies to reduce the productive losses caused by the disease.