Multi‐parental QTL mapping of resistance to white spot of maize (Zea mays) in southern Brazil and relationship to QTLs of other foliar diseases

Abstract

Maize white spot (MWS) is one of the most important foliar diseases in Brazil causing significant yield losses. Breeding genotypes with MWS resistance is the most sustainable alternative for managing such losses; however, their genetic control is poorly understood. Our objectives were to identify genomic regions controlling MWS resistance and to explore the presence of common regions controlling resistance to MWS, grey leaf spot (GLS) and northern corn leaf blight (NCLB). We performed a multi-parental QTL mapping for MWS and GLS resistance with a total of 474 testcrosses and phenotypic data collected in southern Brazil. Six QTLs for MWS resistance on bins 1.03, 1.04, 6.02, 8.05, 1.03, and 10.06 were detected. These findings were compared with previously reported QTLs for NCLB in the same populations, and a common QTL region (bin 8.05) controlling MWS and NCLB resistances was identified. Our findings contribute to a better understanding of MWS resistance by revealing three QTLs (bin 6.02, 1.03, and 10.06), to the best of our knowledge, not yet described in the literature, that are valuable for improving MWS resistance and one promising candidate region for multiple disease resistance.

Distribution, Etiology, Molecular Genetics and Management Perspectives of Northern Corn Leaf Blight of Maize (Zea mays L.)

“…Quantitative trait loci (QTL) or linkage mapping is an important approach to study polygenic and complex forms of disease tolerance. QTL for NCLB resistance has been established in many populations [13][14][15][16]. The present review lays out the rationale for NCLB disease development, variability and population structure of causal pathogen, genetics of resistance, the progress of gene identification against NCLB, and management strategies.…”

A type VI secretion system effector TseG of Pantoea ananatis is involved in virulence and antibacterial activity

“…P. ananatis is a pathogen of many plants, including maize, rice, onion, and other crops, resulting in significant agricultural losses in several regions (Azad et al., 2000 ; De Maayer et al., 2012 ; Polidore et al., 2021 ). Upon plant infection, these bacteria cause internal rotting, dieback, and blight, especially in maize and onions (Goszczynska et al., 2007 ; Kistner et al., 2021 ; Shin et al., 2023 ). P. ananatis is widely distributed in nature, including in a variety of animals, plants, insects, the human body, soil, rivers, and refrigerated food; however, the majority of P. ananatis strains have been isolated from plants (Coutinho & Venter, 2009 ; Ercolini et al., 2006 ).…”

“…Upon plant infection, these bacteria cause internal rotting, dieback, and blight, especially in maize and onions (Goszczynska et al, 2007;Kistner et al, 2021;Shin et al, 2023). P. ananatis is widely distributed in nature, including in a variety of animals, plants, insects, the human body, soil, rivers, and refrigerated food; however, the majority of P. ananatis strains have been isolated from plants (Coutinho & Venter, 2009;Ercolini et al, 2006).…”

Biocontrol potential of actinobacteria against Pantoea ananatis, the causal agent of maize white spot disease

“…Maize white spot, caused by the bacterium Pantoea ananatis, emerged as one of the most important foliar maize disease widely distributed in America (Kistner et al, 2021), Africa (Goszczynska et al, 2007), Europe (Krawczyk et al, 2010) and Asia (Cui et al, 2022), and is considered a potential threat to maize production in regions where high humidity and low night time temperatures are prevalent during the growing season. Symptoms are initially expressed as aqueous lesions in the basal leaves, rapidly spreading to the plant with a chlorotic appearance at more advanced stages of the disease, causing drastically reducing cycle and photosynthetic area of the affected plants (Derera et al, 2007).…”

“…The adoption of maize resistant hybrids and pesticides application have been employed for maize white spot disease management. The use of disease-resistant genotypes has been the most efficient strategy to reduce yield losses and collaborate with environmental preservation, although it presents limitations and increases the cost of production (Mueller et al, 2020;Kistner et al, 2021). In the other side, the indiscriminate use of pesticides can lead to negative environmental impacts, damage to human health and the selection of resistant pathogens (Bastos et al, 2019;Lopes-Ferreira et al, 2022).…”