Miriam Nancy Salazar-Vidal, Melissa A Draves, Sarah L Fitzsimmons, Zachary B Traylor, Sherry Flint-Garcia
{"title":"How to Harvest and Store Corn (<i>Zea mays</i>).","authors":"Miriam Nancy Salazar-Vidal, Melissa A Draves, Sarah L Fitzsimmons, Zachary B Traylor, Sherry Flint-Garcia","doi":"10.1101/pdb.prot108639","DOIUrl":"https://doi.org/10.1101/pdb.prot108639","url":null,"abstract":"<p><p>Harvest scheduling, seed drying, and good storage practices are essential for maize research to avoid negative impacts on the quality of the seeds and to maximize seed viability. Embryo growth and accumulation of energy reserves in the endosperm are completed ∼40 days after pollination, of which the last 10-20 days are devoted to maturation and desiccation. Seed maturity is affected by many factors including temperature, day length, humidity, and soil moisture. Once seeds are mature, they must be harvested. Hand harvesting, which allows for greater control and minimizes ear damage, is primarily used in genetic nurseries and general research because each genotype is represented by a small number of plants. Hand harvesting is also used where there is a mix of manually pollinated and undesired open pollinated ears, and can be a selective harvest depending on the research objectives. However, hand harvesting is more labor-intensive and time-consuming compared to combine harvesting. If harvesting a yield trial, where the purpose is to collect yield data and identify promising genotypes, the use of a combine (not described in this protocol) is critical to consistently capture grain weight, moisture, and test weight for each plot. Following harvest, materials must be dried to the appropriate moisture content before storage. Corn is typically stored using the \"active collection\" model, with temperatures set between 5°C and 10°C and low relative humidity. This harvest protocol is intended to assist laboratories that are new to maize research and may be modified based on project goals, genetic material, equipment, or available space.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miriam Nancy Salazar-Vidal, Melissa A Draves, Sarah L Fitzsimmons, Zachary B Traylor, William F Tracy, Sherry Flint-Garcia
{"title":"How to Monitor Growth and Identify Developmental Stages of Maize (<i>Zea mays</i>).","authors":"Miriam Nancy Salazar-Vidal, Melissa A Draves, Sarah L Fitzsimmons, Zachary B Traylor, William F Tracy, Sherry Flint-Garcia","doi":"10.1101/pdb.prot108637","DOIUrl":"https://doi.org/10.1101/pdb.prot108637","url":null,"abstract":"<p><p>Properly characterizing the stages of corn growth is critical to conducting successful experiments in maize genetics and breeding. Specifically, accurately identifying stages of growth is required to perform developmentally dependent sampling or data collection, to predict time to flowering and seed maturation, and to allow for comparisons between different lines and populations based on developmental time. In this protocol, we summarize previous knowledge about maize development and describe how to monitor these stages in the reference inbred line B73, a yellow dent corn.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Harrison Hall, Peyton Sorensen, Tiffany Jamann, Santiago Mideros
{"title":"Inoculation of Maize Roots with <i>Globisporangium ultimum</i> var. <i>ultimum</i> to Study Pythium Root Rot.","authors":"Harrison Hall, Peyton Sorensen, Tiffany Jamann, Santiago Mideros","doi":"10.1101/pdb.prot108640","DOIUrl":"https://doi.org/10.1101/pdb.prot108640","url":null,"abstract":"<p><p>Maize is a globally important field crop for food and fuel production. Yield can be affected early in the growing season by oomycete and fungal pathogens that cause root rot or prevent seed germination. The diseases caused by these pathogens are referred to as seedling blights, root rots, or damping off. Pythium root rot is one of the most significant of these diseases. The disease is caused by multiple species of the oomycete genera <i>Globisporangium</i> and <i>Pythium</i> and results in significant yield losses due to reduced seed germination and reduced vigor of surviving seedlings. In this protocol, we mimic the natural infection process by mixing the inoculum into the potting media in which seeds are planted. Then, we flood the seeds daily for several days in large plastic totes to induce flooding conditions. Disease severity is assessed using stand counts and measuring root mass and length. This protocol allows researchers to investigate quantitative differences in disease symptoms, isolate aggressiveness, as well as levels of host resistance. This protocol was developed for the pathogen <i>Globisporangium ultimum</i> var. <i>ultimum</i>, but it can be adapted for other species.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rashmi Pokhrel, Alexander Mullens, Peyton Sorensen, Santiago Mideros, Tiffany Jamann
{"title":"High-Throughput Fluorescence Microscopy Using Aniline Blue Staining to Study the Maize<i>-Exserohilum turcicum</i> Pathosystem.","authors":"Rashmi Pokhrel, Alexander Mullens, Peyton Sorensen, Santiago Mideros, Tiffany Jamann","doi":"10.1101/pdb.prot108643","DOIUrl":"https://doi.org/10.1101/pdb.prot108643","url":null,"abstract":"<p><p>Maize is a globally important grain crop that is important for food and fuel. Northern corn leaf blight, caused by <i>Exserohilum turcicum</i>, is an important fungal foliar disease of maize that is highly prevalent and causes yield losses globally. Microscopy can be used to visualize plant-fungal interactions on a cellular level, which enables pathology and genetics studies. Host resistance and isolate aggressiveness can be characterized at different stages of disease development, which enables a more detailed understanding of the pathogenesis process and host-pathogen interactions. Our protocol outlines an efficient, cost-effective method for staining <i>E. turcicum</i> tissue on inoculated maize leaves and visualizing samples using a compound fluorescence microscope. This protocol uses KOH treatment followed by aniline blue staining, which stains glucans present in plant and fungal cell walls, and samples are visualized using fluorescence microscopy. Quantitative data about fungal structures including the conidia, hyphal structures, and appressoria, the structures formed to push through the plant leaf surface after conidia have germinated, can be obtained from the images generated using this technique. Visualization of these structures can help pathologists understand plant-pathogen interactions for maize and <i>E. turcicum</i> This method has advantages over other methods because the stain is less toxic than other available stains, samples can be processed in a more high-throughput manner than other protocols, and the required supplies are relatively inexpensive.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah L Fitzsimmons, Miriam Nancy Salazar-Vidal, Zachary B Traylor, Melissa A Draves, Sherry Flint-Garcia
{"title":"How to Pollinate Corn (<i>Zea mays</i>).","authors":"Sarah L Fitzsimmons, Miriam Nancy Salazar-Vidal, Zachary B Traylor, Melissa A Draves, Sherry Flint-Garcia","doi":"10.1101/pdb.prot108638","DOIUrl":"https://doi.org/10.1101/pdb.prot108638","url":null,"abstract":"<p><p>Corn, or maize, is an economically important crop and frequently used model organism for genetic studies. Controlled pollinations are essential to the execution of these studies. This protocol outlines the basic steps in planning, setting up, and making manual pollinations. In addition, a method of extending pollen for multiple pollinations, as well as types of pollinations and their respective labeling schemes, are detailed. A troubleshooting guide is provided with solutions for common problems one might encounter when making manual pollinations. Although growing conditions and germplasm may cause slight deviations from this protocol, the basic principles can be applied to any corn research program.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Uses and Opportunities for Ethyl Methanesulfonate Mutagenesis in Maize.","authors":"Rajdeep S Khangura, Norman B Best, Brian P Dilkes","doi":"10.1101/pdb.top108504","DOIUrl":"https://doi.org/10.1101/pdb.top108504","url":null,"abstract":"<p><p>Creating mutations in maize has provided key foundational information for our mechanistic understanding of genetics, evolution, and even the role of chromosomes as units of inheritance. Chemical mutagenesis is used in biological research to create novel genetic variation. Ethyl methanesulfonate (EMS) is an alkylating agent and a highly potent and frequently used mutagen. EMS mutagenesis can be used to identify genes based on phenotypes induced by mutagenesis (forward genetics) and to validate the functions of genes by independently creating multiple mutant alleles in known genes (reverse genetics). Due to our ability to collect huge quantities of maize pollen and to easily apply pollen to the silks of maize ears to conduct pollination and achieve hundreds of fertilization events, pollen EMS mutagenesis is uniquely facile in maize. While pollen EMS mutagenesis is commonly performed, treatment of maize seeds with EMS is also highly effective, and can be used for certain research objectives that are difficult to achieve with pollen mutagenesis, such as recovering mutant sectors. The alkylation of guanine residues by EMS primarily results in G > A or C > T transitions in the DNA, making the molecular profiling of mutations caused by EMS easy, with an extremely low false positive rate. EMS is hydrophilic, has a moderate half-life in water, and is sensitive to light and high temperatures. With appropriate precautions in research settings, EMS can be relatively safe to handle. Here, we provide an introduction to chemical mutagenesis via EMS, including some history on its use in maize and the considerations for the effective and safe design of mutagenesis experiments with EMS in maize.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Lipps, Peyton Sorensen, Mara Krone, Santiago Mideros, Tiffany Jamann
{"title":"Inoculation of Maize Ears with <i>Fusarium graminearum</i> to Study Gibberella Ear Rot.","authors":"Sarah Lipps, Peyton Sorensen, Mara Krone, Santiago Mideros, Tiffany Jamann","doi":"10.1101/pdb.prot108641","DOIUrl":"https://doi.org/10.1101/pdb.prot108641","url":null,"abstract":"<p><p>Maize is an important food and fuel crop globally. Ear rots, caused by fungal pathogens, are some of the most detrimental maize diseases, due to reduced grain yield and the production of harmful mycotoxins. Mycotoxins are naturally occurring toxins produced by certain fungal species that can cause acute and chronic health issues in humans and animals that consume mycotoxin-contaminated grain. Pathogens can infect the developing ear through silks, or through wounds in the ears produced by pests. Plants naturally develop genetic resistance to pathogens. The maize genes involved in resistance to the pathogen may be different, depending on whether the ear was infected via silks or wounds. To differentiate between these two forms of resistance, natural infections can be reproduced by injecting inoculum through the silk channel, or by producing wounds using a needle, and introducing inoculum directly onto developing ears. Our protocol describes a technique used to inoculate developing maize ears with <i>Fusarium graminearum</i>, one of the fungal species that causes ear rot. We describe both silk channel and side needle inoculation techniques. Our protocol uses a backpack inoculator for both methods of infection, allowing for high-throughput inoculations, which are necessary for large field experiments. After harvest, the ears are visually rated on a percentage of disease scale. The protocol results in quantitative data that can be used for research on elucidating genetic resistance to fungal pathogens to assist breeding selections, and to understand plant-pathogen interactions of ear rots in maize.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zachary B Traylor, Sarah L Fitzsimmons, Melissa A Draves, Miriam Nancy Salazar-Vidal, William F Tracy, Sherry Flint-Garcia
{"title":"Planting, Pollinating, Harvesting, and Monitoring Growth in Maize (<i>Zea mays</i>) for Research.","authors":"Zachary B Traylor, Sarah L Fitzsimmons, Melissa A Draves, Miriam Nancy Salazar-Vidal, William F Tracy, Sherry Flint-Garcia","doi":"10.1101/pdb.top108444","DOIUrl":"https://doi.org/10.1101/pdb.top108444","url":null,"abstract":"<p><p><i>Zea mays</i>, also known as maize or corn, is a staple crop as well as a classical model organism for plant genetic studies and research. To conduct maize research, plants must be properly cultivated in field or greenhouse conditions to ensure reproductive success and safeguard genetic identity through controlled pollinations. Genetic studies require knowing which alleles or genetic combinations (genotype) are present in an individual so the geneticist can create new combinations or select the desired genotypes. In order to determine and maintain the genetic identity of a corn plant and make precise selections of male and female plants, reproductive structures must be covered and isolated prior to silking and anthesis, or pollen shed. Doing so allows experimenters to make controlled pollinations to produce the desired genotype. Successful pollination of corn requires proper field design and preparation, careful planting to maintain distinct genetic families, and careful monitoring of growth and husbandry followed by proper harvest and seed storage. These activities have been optimized over the past 100 years. In this review, we summarize each step needed to produce a generation of corn from planting to harvest.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Mullens, Peyton Sorensen, Julian Cooper, Tiffany Jamann
{"title":"Inoculation of Maize Leaves with the Bacterial Foliar Pathogen <i>Clavibacter nebraskensis</i>.","authors":"Alexander Mullens, Peyton Sorensen, Julian Cooper, Tiffany Jamann","doi":"10.1101/pdb.prot108642","DOIUrl":"https://doi.org/10.1101/pdb.prot108642","url":null,"abstract":"<p><p>Maize significantly contributes to food and fuel production. Yields can be reduced due to foliar diseases, which reduce photosynthetic leaf area. The bacterial foliar disease Goss's wilt (caused by <i>Clavibacter nebraskensis</i>) can cause significant yield losses in susceptible maize varieties. <i>C. nebraskensis</i> can infect leaves through wounds and colonize the vascular tissue of the leaf. We present a protocol that replicates this process with the use of a \"clapper\" with pins on one end to create wounds and a sponge soaked in inoculum on the other end, which allows for efficient field inoculations of maize leaves. Disease severity is then rated on a percentage scale multiple times over the season to generate an area under disease progress curve (AUDPC). Genetic host resistance is one of the most effective forms of foliar disease control in maize, as there are few effective forms of chemical control for bacterial diseases that affect maize. Screening for resistance in diverse germplasm, or for fine mapping a specific resistance gene, requires inoculating large populations in the field for obtaining phenotypic data. Our high-throughput protocol allows for large-scale disease evaluations and is useful for finding forms of genetic resistance or to understand plant-pathogen interactions of bacterial foliar pathogens.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ethyl Methanesulfonate Treatment of Maize Seed for Recovery of Vegetative Mutant Sectors and Segregating Germinal Mutations.","authors":"Rajdeep S Khangura, Norman B Best, Brian P Dilkes","doi":"10.1101/pdb.prot108650","DOIUrl":"https://doi.org/10.1101/pdb.prot108650","url":null,"abstract":"<p><p>Seed mutagenesis using alkylating chemical agents such as ethyl methanesulfonate (EMS) can generate somatic and germinal mutations in many plant species. In monoecious plants like maize, the sperm- and egg-producing reproductive germlines are derived from distinct cell lineages in the embryo. This separation results in independent mutations inherited via the egg and sperm lineages and prevents the recovery of recessive mutant phenotypes in diploid progeny after the first round of self-pollination. Thus, two generations of self-pollination are required to screen for recessive mutations when conducting seed mutagenesis. The additional time and manual self-pollination make this approach laborious. However, a high mutation rate and the ability to screen for somatic sectors in heterozygous mutant plants and other defined genetic backgrounds make seed mutagenesis an effective but underutilized mutagenesis tool for maize research. This protocol provides the directions and optimization steps to perform effective seed mutagenesis in maize. A high frequency of somatic mutations from seed mutagenesis can be achieved, but comes at the expense of poor and disordered growth, failure to form reproductive structures, and low or no seed production at high EMS concentrations or long contact times. In experiments where germinal mutations are a goal, an optimum dose of EMS is required in the first generation. Maize genetic backgrounds vary in their sensitivity to EMS, requiring some pilot testing in new genetic backgrounds. Researchers using this protocol can carry out seed mutagenesis safely and effectively to develop libraries of mutants or alleles for various experiments.</p>","PeriodicalId":10496,"journal":{"name":"Cold Spring Harbor protocols","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144215149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}