Southern Leaf Blight Research Articles

The ZmCPK39-ZmDi19-ZmPR10 immune module regulates quantitative resistance to multiple foliar diseases in maize.

Gray leaf spot, northern leaf blight and southern leaf blight are three of the most destructive foliar diseases affecting maize (Zea mays L.). Here we identified a gene, ZmCPK39, that encodes a calcium-dependent protein kinase and negatively regulates quantitative resistance to these three diseases. The ZmCPK39 allele in the resistant line displayed significantly lower pathogen-induced gene expression than that in the susceptible line. A marked decrease in ZmCPK39 abundance mitigated the phosphorylation and degradation of the transcription factor ZmDi19. This led to elevated expression of ZmPR10, a gene known to encode an antimicrobial protein, thereby enhancing maize resistance to foliar diseases. Moreover, the F1 hybrid with reduced ZmCPK39 expression favored disease resistance, thereby increasing yield. Hence, the discovery of the ZmCPK39-ZmDi19-ZmPR10 immune module provides insight into the mechanisms underlying broad-spectrum quantitative disease resistance and also offers a new avenue for the genetic control of maize foliar diseases.

The quantification of southern corn leaf blight disease using deep UV fluorescence spectroscopy and autoencoder anomaly detection techniques.

Southern leaf blight (SLB) is a foliar disease caused by the fungus Cochliobolus heterostrophus infecting maize plants in humid, warm weather conditions. SLB causes production losses to corn producers in different regions of the world such as Latin America, Europe, India, and Africa. In this paper, we demonstrate a non-destructive method to quantify the signs of fungal infection in SLB-infected corn plants using a deep UV (DUV) fluorescence spectrometer, with a 248.6 nm excitation wavelength, to acquire the emission spectra of healthy and SLB-infected corn leaves. Fluorescence emission spectra of healthy and diseased leaves were used to train an Autoencoder (AE) anomaly detection algorithm-an unsupervised machine learning model-to quantify the phenotype associated with SLB-infected leaves. For all samples, the signature of corn leaves consisted of two prominent peaks around 450 nm and 325 nm. However, SLB-infected leaves showed a higher response at 325 nm compared to healthy leaves, which was correlated to the presence of C. heterostrophus based on disease severity ratings from Visual Scores (VS). Specifically, we observed a linear inverse relationship between the AE error and the VS (R2 = 0.94 and RMSE = 0.935). With improved hardware, this method may enable improved quantification of SLB infection versus visual scoring based on e.g., fungal spore concentration per unit area and spatial localization.

Identification and application of an endophytic fungus Arcopilus aureus from Panax notoginseng against crop fungal disease.

Endophytic fungi are important microbial resources for developing novel antibacterial and antifungal drugs to prevent and control crop diseases. Panax notoginseng has been used as a Chinese medicinal herb for a long time, as it has various bioactivities. However, information on endophytic fungi isolated from Panax notoginseng is rare. In this study, an endophytic fungus known as SQGX-6, which was later identified as the golden hair fungus Arcopilus aureus, was isolated from Panax notoginseng. SQGX-6 was extracted using ethyl acetate, and the active components of the fungus were identified using ultra-performance liquid chromatography-mass spectrometry (UHPLC-MS). The antifungal and antioxidant activities of the extract were determined and evaluated in vitro and in vivo. SQGX-6 and its extract inhibited the growth of Corn stalk rot (Fusarium graminearum), Corn southern leaf blight (Helminthosporium maydis), and Tomato gray mold (Botrytis cinerea) in vitro. The free radical scavenging rates for 2,2-Diphenyl-1-pyridinyl hydrazide (DPPH) radical scavenging activity, 3-Ethylbenzothiazoline-6-Sulfonic Acid Radical scavenging (ABTS) activity were also downregulated by the SQGX-6 extract. In vivo, the SQGX-6 extract inhibited the mycelial growth rates of the three aforementioned fungi and downregulated malondialdehyde (MDA) content and upregulated peroxidase (POD) and phenylalanine ammonia-lyase (PAL) content in fruits, leading to significant reduction in damage to cherry tomatoes caused by Botrytis cinerea. UHPLC-MS was performed to identify various active substances, including Alkaloids, Azoles, Benzofurans, Coumarins, Flavonoids, Organic acids, Phenols, and plant growth regulators contained in the extract. These results suggested that the endophytic fungus SQGX-6 of Panax notoginseng and its extract have excellent antifungal and antioxidant activities, and thus, it is an important microbial resource for the developing novel drugs against plant fungal infections.

Trichoderma harzianum Cellulase Gene thph2 Affects Trichoderma Root Colonization and Induces Resistance to Southern Leaf Blight in Maize.

Trichoderma, widely distributed all over the world, is commonly found in soil and root ecosystems. It is a group comprising beneficial fungi that improve plant disease resistance and promote plant growth. Studies have shown that Trichoderma cellulases can also improve plant disease resistance. Based on previous studies, we reported that a C6 zinc finger protein (Thc6) regulates two cellulase genes, thph1 and thph2, to induce ISR responses in plants. Therefore, in this study, we focused on the role of thph2 in the colonization of maize roots by T. harzianum and the induction of systemic resistance against southern leaf blight. The results showed that thph2 had a positive regulatory effect on the Trichoderma colonization of maize roots. After the root was treated with Trichoderma, the leaf defense genes AOS, LOX5, HPL, and OPR1 were expressed to resist the attack of Cochliobolus heterostrophus. The pure Thph2 protein also resulted in a similar induction activity of the AOS, LOX5, HPL, and OPR1 expression in maize roots, further demonstrating that thph2 can induce plant defense responses and that signal transduction occurs mainly through the JA signaling pathway.

Agrobacterium tumefaciens-mediated transformation of Nigrospora sp. isolated from switchgrass leaves and antagonistic toward plant pathogens

Nigrospora is a diverse genus of fungi colonizing plants through endophytic, pathogenic, or saprobic interactions. Endophytic isolates can improve growth and development of host plants, as well as their resistance to microbial pathogens, but exactly how they do so remains poorly understood. Developing a reliable transformation method is crucial to investigate these mechanisms, in particular to identify pivotal genes for specific functions that correlate with specific traits. In this study, we identified eight isolates of Nigrospora sp. internally colonizing the leaves of switchgrass plants cultivated in North Carolina. Using an Agrobacterium tumefaciens-mediated transformation approach with control and GFP-expressing vectors, we report the first successful transformation of two Nigrospora isolates. Finally, we demonstrate that wild-type and transgenic isolates both negatively impact the growth of two plant pathogens in co-culture conditions, Bipolaris maydis and Parastagonospora nodorum, responsible for the Southern Leaf Blight and Septoria Nodorum Blotch diseases, respectively. The GFP-transformed strains developed here can therefore serve as accurate reporters of spatial interactions in future studies of Nigrospora and pathogens in the plant. Finally, the transformation method we describe lays the foundation for further genetic research on the Nigrospora genus to expand our mechanistic understanding of plant-endophyte interactions.

Monitoring Maize Leaf Spot Disease Using Multi-Source UAV Imagery

Maize leaf spot is a common disease that hampers the photosynthesis of maize by destroying the pigment structure of maize leaves, thus reducing the yield. Traditional disease monitoring is time-consuming and laborious. Therefore, a fast and effective method for maize leaf spot disease monitoring is needed to facilitate the efficient management of maize yield and safety. In this study, we adopted UAV multispectral and thermal remote sensing techniques to monitor two types of maize leaf spot diseases, i.e., southern leaf blight caused by Bipolaris maydis and Curvularia leaf spot caused by Curvularia lutana. Four state-of-the-art classifiers (back propagation neural network, random forest (RF), support vector machine, and extreme gradient boosting) were compared to establish an optimal classification model to monitor the incidence of these diseases. Recursive feature elimination (RFE) was employed to select features that are most effective in maize leaf spot disease identification in four stages (4, 12, 19, and 30 days after inoculation). The results showed that multispectral indices involving the red, red edge, and near-infrared bands were the most sensitive to maize leaf spot incidence. In addition, the two thermal features tested (i.e., canopy temperature and normalized canopy temperature) were both found to be important to identify maize leaf spot. Using features filtered with the RFE algorithm and the RF classifier, maize infected with leaf spot diseases were successfully distinguished from healthy maize after 19 days of inoculation, with precision >0.9 and recall >0.95. Nevertheless, the accuracy was much lower (precision = 0.4, recall = 0.53) when disease development was in the early stages. We anticipate that the monitoring of maize leaf spot disease at the early stages might benefit from using hyperspectral and oblique observations.

Genome assembly of KA105, a new resource for maize molecular breeding and genomic research

Superior inbred lines are central to maize breeding as sources of natural variation. Although many elite lines have been sequenced, less sequencing attention has been paid to newly developed lines. We constructed a genome assembly of the elite inbred line KA105, which has recently been developed by an artificial breeding population named Shaan A and has shown desirable characteristics for breeding. Its pedigree showed genetic divergence from B73 and other lines in its pedigree. Comparison with the B73 reference genome revealed extensive structural variation, 58 presence/absence variation (PAV) genes, and 1023 expanded gene families, some of which may be associated with disease resistance. A network-based integrative analysis of stress-induced transcriptomes identified 13 KA105-specific PAV genes, of which eight were induced by at least one kind of stress, participating in gene modules responding to stress such as drought and southern leaf blight disease. More than 200,000 gene pairs were differentially correlated between KA105 and B73 during kernel development. The KA105 reference genome and transcriptome atlas are a resource for further germplasm improvement and surveys of maize genomic variation and gene function.

ZmAGO18b negatively regulates maize resistance against southern leaf blight.

Here, we report that ZmAGO18b encoding an argonaute protein is a negative regulator of maize resistance against southern leaf blight. Southern leaf blight caused by fungal pathogen Cochliobolus heterostrophus is a destructive disease on maize throughout the world. Argonaute (AGO) proteins, key regulators in small RNA pathway, play important roles in plant defense. But whether they have function in maize resistance against C. heterostrophus is unknown. Association analysis between the nucleic variation of 18 ZmAGO loci with disease phenotype against C. heterostrophus was performed, and the ZmAGO18b locus was identified to be associated with resistance against C. heterostrophus. Overexpression of ZmAGO18b gene suppresses maize resistance against C. heterostrophus, and mutation of ZmAGO18b enhances maize resistance against C. heterostrophus. Further, we identified the resistant haplotype of ZmAGO18b by association analysis of natural variation in ZmAGO18b genomic DNA sequences with seedling resistance phenotypes against C. heterostrophus and confirmed the resistant haplotype is co-segregated with resistance phenotypes against C. heterostrophus in two F2 populations. In sum, this study reports that ZmAGO18b negatively regulates maize resistance against C. heterostrophus.

Assessment of yield loss and avoidable yield loss due to southern leaf blight of maize and development of yield loss prediction model

Assessment of yield loss and avoidable yield loss due to southern leaf blight of maize and development of yield loss prediction model

CHEMICAL CONTROL OF SOUTHERN LEAF BLIGHT OF MAIZE CAUSED BY HELMINTHOSPORIUM MAYDIS

Southern Leaf Blight of maize (SLBM) is a severe disease affecting maize crop in Pakistan. This disease causes considerable losses in maize crop every year. To avoid this loss, a study was conducted to check the efficacy of four fungicides and one control, tested against maize variety Malka-2016. The experiment was conducted at Plant Pathology AARI Research area, Faisalabad, during 2021-22. The result showed that Propiconazole (Tilt 25% WP) was found to be the most effective fungicide to control the leaf Blight of maize followed by Dithane M-45 (Mancozeb 80%WP) and Kavach (Chlorothalonil 75%WP). The Blitox-50 (Copper oxychloride 50%WP) was the least effective against the disease. The Propiconazole (Tilt 25% WP) control the disease 80 % over the check. Similarly, Dithane M-45 (Mancozeb 80 %) controls the disease 70.83 % and Chlorothalonil by 59 %. The least effective fungicide was Blitox-50 (Copper oxychloride 50 %) which control the disease 42.5% over the check.

A leucine-rich repeat receptor kinase gene confers quantitative susceptibility to maize southern leaf blight.

Southern leaf blight (SLB), caused by the necrotrophic fungal pathogen Cochliobolus heterostrophus (anamorph Bipolaris maydis), is a major foliar disease which causes significant yield losses in maize worldwide. A major quantitative trait locus, qSLB3.04 , conferring recessive resistance to SLB was previously mapped on maize chromosome 3. Using a combination of map-based cloning, association analysis, ethyl methanesulfonate and transposon mutagenesis, and CRISPR-Cas9 editing, we demonstrate that a leucine-rich repeat receptor-like kinase gene which we have called ChSK1 (Cochliobolus heterostrophus Susceptibility Kinase 1) at qSLB3.04 causes increased susceptibility to SLB. Genes of this type have generally been associated with the defense response. We present evidence that ChSK1 may be associated with suppression of the basal immune response. These findings contribute to our understanding of plant disease susceptibility genes and the potential to use them for engineering durable disease resistance.

Marker-assisted pyramiding of southern leaf blight resistance QTLs qSLB3.1 and qSLB8.1 in maize (Zea mays)

Southern leaf blight (SLB) is one of the major diseases that cause substantial yield losses in maize (Zea mays L.) worldwide. Stacking broad-spectrum resistance genes/QTLs into prevalent cultivars is the prerequisite for durable disease resistance breeding programme. Therefore, a study was carried at the research farm and molecular biology laboratory of School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, Punjab during 2017–21 to introgress SLB resistance QTLs from two donors, viz. CM139 (qSLB3.1) and LM5 (qSLB8.1) into CM140 inbred using marker-assisted backcross breeding (MABB). Crosses were made between CM139 × CM140 and LM5 × CM140 to generate two separate F1s. Each F1 was backcrossed twice to generate BC2F1 progenies. Foreground selection was performed at each step using linked flanking markers to each QTL and also evaluated for SLB resistance. The selected heterozygous BC2F1 plants from each cross were inter-crossed to combine qSLB3.1 and qSLB8.1 in the same genetic background. The F2 population was also evaluated phenotypically for SLB resistance and other morphological traits. A total of 18 plants were obtained having both the QTLs with homozygous donor alleles. The F2 plants having both QTLs and singly in the homozygous state were advanced to generate F3 progenies. The pyramided lines exhibited 29% lesser disease severity than the lines with either QTL. The present results indicated that additive effects of the QTLs for SLB resistance played an important role among these lines. To our best knowledge, this is the first report for the pyramiding of QTLs associated with SLB resistance. The pyramided lines would serve as potential donors in maize breeding programs.

Prevalence of Southern Leaf Blight of Maize in two major maize producing states of India

Southern corn leaf blight (SCLB) or Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize in the eastern and north-eastern part of India. Hence, to assess the severity and distribution of the disease in two distinct and major maize growing states i.e. Mizoram and West Bengal were selected. A roving survey was conducted under different agro-climatic conditions during the kharif season of 2019 and 2020 in three districts of West Bengal and as well as in Mizoram. The survey results revealed that SCLB was more prevalent in the plains of West Bengal in comparison to hilly areas of Mizoram. The mean SCLB incidence varied from 18.87% in Zemabawk, Mizoram to 63.22% in institutional farm, C-block, of BCKV, West Bengal. The mean disease severity ranged from 10.06 % in Muthi, Mizoram to 22.09% in Instructional Farm, Jaguli, BCKV, West Bengal. Both disease incidence and severity were highest at 99 DAS in all the locations surveyed. Successive surveys of SCLB in the maize growing belts across the country need to be conducted to develop a better understanding about the disease prevalence, intensity and severity under different agro-ecological conditions.

Evaluation of Fungicides, Botanicals and Biocontrol Agents for Management of Southern Leaf Blight of Maize (Bipolaris maydis)with Effective Benefit Cost Ratio

Southern leaf blight of maize (Bipolaris maydis) is one of the major disease in many countries including India. An experiment was conducted for two consecutive years during rabi 2019 and 2020 to develop an integrated management of southern leaf blight of maize using fungicides, botanicals and bioagents under natural field conditions. Propiconazole was found to be the best and showed 100% mycelial growth inhibition in vitro at 0.1%. Among the botanicals, citronella showed 99.70% mycelial growth inhibition and Trichoderma harzianum was found to be the best with 84.26% mycelial growth inhibition among the biocontrol agents. The results of the field trials showed the highest yield performance (2601.71 kg ha-1) and percent reduction in disease severity over control of 61.70 % in the treatment comprising of seed treatment+spraying with propiconazole 25% EC @ 1% which was followed by treatment comprised of spraying with citronella @ 0.1% (2445.33 kg ha-1) and spraying with propiconazole 25% EC @ 0.1% (2349.26 kg ha-1). Highest BC ratio was obtained in seed treatment+spraying with propiconazole 25% EC @ 1% (4.05) followed by spraying with Trichoderma harzianum @ 4 g (3.71) and seed treatment+spraying with Trichoderma harzianum @ 4 g (3.69). The results showed that seed treatment+spraying with propiconazole 25% EC @ 1% was significantly superior over other treatments.

Physiological and Molecular Characteristics of Southern Leaf Blight Resistance in Sweet Corn Inbred Lines

Southern corn leaf blight is one of the most widespread foliar diseases in maize-producing areas worldwide and can seriously reduce the yield and quality of sweet corn. However, the molecular mechanisms underlying the disease in sweet corn have not been widely reported. In this study, two sweet corn inbred lines, resistant K13 (RK13) and susceptible K39 (SK39), were used to explore the disease resistance mechanism of southern leaf blight. We observed morphological characteristics and assessed the changes in protective enzymatic activity in sweet corn leaves after inoculation of C. heterostrophus. RNA-seq was performed to elucidate the transcriptional dynamics and reveal the key pathways involved in southern leaf blight resistance without pathogens (Mock) and at 1 and 3 days post inoculation (1 and 3 dpi). Differentially expressed genes (DEGs) were identified in the SK39 group (including three pairwise combinations: SK39−0d_vs_SK39−1d, SK39−1d_vs_SK39−3d and SK39−1d_vs_SK39−3d), the RK13 group (including three pairwise combinations: RK13−0d_vs_RK13−1d, RK13−1d_vs_RK13−3d and RK13−1d_vs_RK13−3d), and the SK39_vs_RK13 group (including three pairwise combinations: SK39−0d_vs_RK13−0d, SK39−1d_vs_RK13−1d, and SK39−3d_vs_RK13−3d). In our study, 9455 DEGs from the RK13 group, 9626 from the SK39 group, and 9051 DEGs from the SK39_vs_RK13 group were obtained. Furthermore, 2775, 163, and 185 DEGs were co-expressed at SK39_vs_RK13, RK13, and SK39, respectively. A functional analysis of the DEGs revealed that five pathways—i.e., photosynthesis, plant hormone signal transduction, MAPK signaling pathway, phenylpropanoid biosynthesis, and biosynthesis of secondary metabolites—and transcription factor families play crucial roles in disease resistance. The results from the present study enabled the identification of the JA and SA signaling pathways, which are potentially involved in the response to southern leaf blight in maize. Our findings also highlight the significance of ZIM transcription factors and pathogenesis-related (PR) genes during pathogen infection. This study preliminarily explored the molecular mechanisms of the interaction between sweet corn and C. heterostrophus and provides a reference for identifying southern leaf blight resistance genes in the future.

An Improved Genome Sequence Resource of Bipolaris maydis, Causal Agent of Southern Corn Leaf Blight.

An Improved Genome Sequence Resource of Bipolaris maydis, Causal Agent of Southern Corn Leaf Blight.

Computational identification of maize miRNA and their gene targets involved in biotic and abiotic stresses

Plant interactions with biotic and abiotic stresses are complex and entail changes at the transcriptional, cellular and physiological level. MicroRNAs (miRNAs) are small (∼20-24 nt), non-coding RNAs that play a vital role in wide range of biological processes involved in regulation of gene expression through translation inhibition or degradation of their target mRNAs during stress conditions. Therefore, identification of miRNAs and their targets are of immense value in understanding the regulatory networks triggered during stress. Advancement in computational approaches has opened up ways for the prediction of miRNAs and their possible targets with functional pathways. Our objective was to identify miRNA and their potential targets involved in both biotic and abiotic stresses in maize. A total of 2,019,524 downloaded ESTs from dbEST were processed and trimmed by Seq Clean. The program trashed 264,000 and trimmed 284,979 sequences and the resulting 1,755,534 sequences were submitted for clustering and assembled to RepeatMasker and TGICL. A total of 30 miRNAs were found to hybridize with the potential targets of gene families such as CoA ligase, lipoxygenase 1, Terpenoideyclases, Zn finger, transducing, etc. Ten of the identified miRNAs targeted cytochrome c1 family. Zm_miR23 class targeted 11 different genes. The identified targets are involved in the plant growth and development during biotic and abiotic stresses in maize. These miRNAs may be further used for functional analysis. Furthermore, four and two of the miRNA targets were validated in response to waterlogging tolerance and southern leaf blight resistance, respectively, to understand the miRNA-assisted regulation of target miRNAs. The functional annotation of the predicted targets indicated that these stress-responsive miRNAs regulate cellular function; molecular function and biological process in maize at the post-transcriptional level. The present results have paved way towards better understanding the role of miRNAs in the mechanism of stress tolerance in maize.

Study of southern leaf blight (Bipolaris maydis) on maize genotypes and its effect on grain yield

Southern maize leaf blight is known to be the foremost harmful disease of maize crop which causes significant yield loss. In present investigation, 20 maize genotypes were selected for the test against Southern Leaf Blight (SLB) in the prevailing field conditions at Prithu Technical College, Bangaun, Dang, Nepal with an objective to find the new sources of resistance against southern leaf blight disease. Randomized Complete Block Design (RCBD) was used with three replications as the experimental design. The total percentage of infected leaf area per plant was studied for the disease scoring. It was conducted consequently 5 days of interval, for 5 times after 60 days after sowing and disease severity, mean AUDPC were estimated and yield recorded. The tested 20 maize genotypes differed significantly in mean AUDPC values and based on AUDPC values, genotypes were categorized as highly susceptible, susceptible, moderately resistance and resistance category. Maize genotype Rampur-S03F08 (AUDPC value 65) appeared most resistant followed by Across-0091(AUDP value 67.08) and TLBRSO7F16 (AUDPC value 70.41). Significantly highest yield (1.8 t/ha) was found on genotype Rampur-SO3FO8 (1.8 t/ha) followed by Across-0091 (1.65 t/ha) and TLBRSO7F16 (1.63 t/ha). Thus indicating the high yielding and resistance maize genotypes Rampur- S03F08, Across-0091 and TLBRSO7F16 could be developed as the resistant varieties to southern leaf blight disease.

Validation and Characterization of Maize Multiple Disease Resistance QTL.

Southern Leaf Blight, Northern Leaf Blight, and Gray Leaf Spot, caused by ascomycete fungi, are among the most important foliar diseases of maize worldwide. Previously, disease resistance quantitative trait loci (QTL) for all three diseases were identified in a connected set of chromosome segment substitution line (CSSL) populations designed for the identification of disease resistance QTL. Some QTL for different diseases co-localized, indicating the presence of multiple disease resistance (MDR) QTL. The goal of this study was to perform an independent test of several of the MDR QTL identified to confirm their existence and derive a more precise estimate of allele additive and dominance effects. Twelve F2:3 family populations were produced, in which selected QTL were segregating in an otherwise uniform genetic background. The populations were assessed for each of the three diseases in replicated trials and genotyped with markers previously associated with disease resistance. Pairwise phenotypic correlations across all the populations for resistance to the three diseases ranged from 0.2 to 0.3 and were all significant at the alpha level of 0.01. Of the 44 QTL tested, 16 were validated (identified at the same genomic location for the same disease or diseases) and several novel QTL/disease associations were found. Two MDR QTL were associated with resistance to all three diseases. This study identifies several potentially important MDR QTL and demonstrates the importance of independently evaluating QTL effects following their initial identification.

Mapping quantitative trait loci associated with southern leaf blight resistance in maize (Zea mays L.)

AbstractSouthern leaf blight (SLB) caused by the fungus Cochliobolus heterostrophus (Drechs.) Drechs. is a major foliar disease of maize worldwide. Our objectives were to identify quantitative trait loci (QTL) for resistance to SLB and flowering traits in recombinant inbred line (RIL) population derived from the cross of inbred lines LM5 (resistant) and CM140 (susceptible). A set of 207 RILs were phenotyped for resistance to SLB at three time intervals for two consecutive years. Four putative QTL for SLB resistance were detected on chromosomes 3, 8 and 9 that accounted for 54% of the total phenotypic variation. Days to silking and anthesis–silking interval (ASI) QTL were located on chromosomes 6, 7 and 9. A comparison of the obtained results with the published SLB resistance QTL studies suggested that the detected bins 9.03/02 and 8.03/8.02 are the hot spots for SLB resistance whereas novel QTL were identified in bins 3.08 and 8.01/8.04. The linked markers are being utilized for marker‐assisted mobilization of QTL conferring resistance to SLB in elite maize backgrounds. Fine mapping of identified QTL will facilitate identification of candidate genes underlying SLB resistance.