CORN/ENDOPHYTE PARTNERSHIPS FOR ORGANIC FARMERS.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: ACTIVE
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1028979
• Grant No.: 2022-51300-38057
• Cumulative Award Amt.: $1,498,705.00
• Proposal No.: 2022-04037
• Project Start Date: Sep 1, 2022
• Project End Date: Aug 31, 2025
• Grant Year: 2022
• Program Code: [113.A]- Organic Agriculture Research & Extension Initiative

Recipient Organization
MANDAAMIN INSTITUTE INC
7194 MADAUS ST
LAKE GENEVA,WI 531473616

Performing Department
(N/A)

Non Technical Summary
This project builds on decades of research targeting a new type of corn that utilizes partnerships with seed-borne, bacterial endophytes to create environmentally-friendly, nutritious corn that is better adapted to organic farming. The project will develop organic breeding methods, evaluate economic benefits, do on-farm R&D, and breed non-commodity corn varieties suited for organic agriculture. It will engage organic farmers and companies, addressing their needs for: a) yield competitive hybrids with greater nutrient density (methionine and minerals), b) adaptated inbreds for organic conditions (vigor, weed problems, nitrogen limitations), and c) reduced manure inputs and nitrate pollution. The work includes breeding, laboratory and on-farm research by relevant expertise.Outcomes will be vigorous inbreds and hybrids that foster endophyte partners. Such cultivars a) produce competitive yields while reducing fertilizer inputs and excess nitrate soil residues; b) increase nutritional density in grain and silage leading to higher feeding and sales value. Breeding improved field and sweet corn cultivars will be coupled with gaining new information on a) how composition of endophytic communities relates to their functional services of rhizophagy, nutrient uptake and nitrogen fixation; b) how these partnerships function in different inbreds/hybrids/environmental conditions and with different seed drying practices; c) how to test seed for benefits and durability of endophytic partnerships, d) how to optimize the use of soil quality tests, e) how to manage organic manures for optimal endophytic corn performance, soil quality, and environmental benefits, and f) the composition of grain for alternative diets and markets based on this non-commodity corn.

Animal Health Component

40%

Research Effort Categories

Basic

40%

Applied

40%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
202	1510	1081	100%

Knowledge Area
202 - Plant Genetic Resources;

Subject Of Investigation
1510 - Corn;

Field Of Science
1081 - Breeding;

Keywords

methionine

nitrogen

efficiency

fixation

rhizophagy

Goals / Objectives
Our long-term goal is developing climate friendly, high quality, non-commodity corn that utilize partnerships with the microbiome to be more nutrient dense and better adapted to organic soil and weed conditions.Corn is the most grown organic row crop. Organic seed producers and farmers need our non-commodity, robust cultivars, which are, a) productive under organic conditions with weed competition and low available N; and b) provide higher nutritional value grain and thereby higher feeding and financial value. These traits are partially based on plant/microbial partnerships. Connections between corn breeds, soil and manure management and quality, seed borne endophyte communities, rhizophagy, N fixation, mineral uptake efficiency, nutritional value are important. Understanding them will help organic seed companies and farmers.The Mandaamin program has selected for plants that possess specific partnerships with seed-borne endophytes, however there are gaps in our knowledge. Combinations of plants and microbes which partner in rhizophagy cycles produce somewhat differentiated results. Progress was made breeding such plant partnerships but it is not yet clear what the endophytes are, what they do in different parts of the plants, how stabile their communities are from year to year, and how management affects them. It appears that the Mandaamin hybrids are obtaining N from microbial biomass and necromass, and not exclusively from nitrate and ammonium, but we do not know how much. The enhanced uptake of macro and micro nutrients and nitrogen appears paired. Fresh manure application to the Institute's C4-6-based hybrids decreases yield and nutrient uptake but increases those parameters for the commercial hybrid check or for Mandaamin's NG10-based hybrids. Furthermore, N2 fixation (which lowered δ15N in grain) can be substantial but it appears to be specific to certain conditions and hybrids. Based on experience and the literature our key hypotheses are that: 1) development of optimal Mandaamin field and sweet corn hybrids can replace direct application of fresh manures, reduce soil nitrate residues, and increase root biomass relative to conventional hybrids; 2) Mandaamin hybrids can obtain N and minerals more effectively due to a healthier, more strongly branched rooting system in the topsoil, coupled with their consumption of whole microorganisms and the uptake of microbial protein/necromass; 3) fresh organic manures interfere with rhizophagy in C4-6 based hybrids due to bacterial interference with the seed-borne community; 4) soil organic N/soil protein buildup (with green manures, and animal manures) will enhance the productivity of the Mandaamin hybrids; 5) microbes living in foliar tissues of the Mandaamin hybrids, and especially in trichomes, can fix N2; 6) hybrids differ in their regulation of rhizophagy and N2 fixation through how they interact with bacteria but these capacities can be optimized through selection; 7) environments, manuring and breeding/seed production practices can positively or negatively affect composition of the next generation of seed borne endophytes.In addition to these hypotheses, organic farmers and seed companies want to know how to manage endophytes in our hybrids. They wanted to understand how manure, direction of crossing when making hybrids, harvest date and seed drying date and conditions affect endophyte function.To achieve our objectives we will:Breed and select field and sweet corn varieties for endophytes and N efficiency/fixation.Characterize the cultivars for endophytes, agronomic value and nutritional density.Test hypotheses linking seed microbiota, soil and manure quality characteristics, plant/microbial partnerships, root growth and health, grain production and nutrient density.Characterize the populations of seed borne endophytes, their functional capacity, and their durability when plants are grown on different sites with and without manure.Develop understanding of and screening protocols for selecting for plant/endophyte partnership performance in different cultivars, including assessing rhizophagy and N2 fixation.Address questions posed by farmers and seed companies about managing endophytes.

Project Methods
Research methods. Towards developing practical screening methods, in WI seedling roots from breeding lines or hybrids will be grown in sterile media and assessed for microbial colonization of root cells and movement of bacteria from root hairs, and superoxide production by plants and nitric oxide production by endophytes. Seedlings grown in containers on N-limited soil media will also be assessed for chlorophyll content, and tissues will be assessed microscopically for microbial components and metabolites.Seedling assays will also test the effects of harvest timing and drying on rhizophagy and N efficiency. Relevant inbreds will be harvested at weekly intervals from before black layer to 15 % moisture in the field. Seed will be dried to approximately 12 and 7% moisture. Seedling roots from this seed will then be assessed for rhizophagy using sterile media. Seedlings will also be grown in N-limited media and foliar trichomes and chlorophyll scores will be examined. Effects of direction of crossing will also be tested. Hybrid seedlings should demonstrate to what degree the maternal phenotype of microbial partnership dominates.Field corn breeding. Diverse, relevant breeding families will be sequentially self-pollinated while under selection in summer nurseries in WI and winter nurseries. Hand pollination occurs in WI on approximately 2,000 rows selected from the best breeding families. 200 rows comprising mostly of later maturing breeding families or hybrids will be grown each summer in Central IL under organic conditions, inoculated for a palette of foliar disease, hand pollinated, and selected for disease resistance and agronomic traits.Early yield testing: In WI replicated yield trials trials on two sites for two years precede strip trials. Yield, grain moisture at harvest, and plant intactness at harvest (lodging) are criteria. Plot size is mostly 2 or 4 rows wide x approximately 20 feet long, with two or three replications per site. Hybrid testing begins at the S3 level of inbreeding. Local yield trials test up to 1,000 different hybrid combinations with one site considered to be low soil nutrient availability, and another medium or high. Feedback from yield trials determines selection. Successful inbreds will be bulked and released for further testing or direct commercialization after the S6 to S8 stage. Projected outputs are 4-8 finished hybrids for strip testing each year of the project based on performanceMandaamin Institute will rent local organic fields to establish isolations for producing hybrid seed allowing sufficient seed for trials with cooperating farmers and seed companies.A clustered set of ten inbreds and ten hybrids will be planted in replicate 4 row plots on an organically managed, moderately N limited site in Wisconsin each year of the project across manured and not manured strips. The inbreds will be selected from N efficient families. Two conventionally bred, ex-PVP inbreds and the hybrid between them will be chosen as control treatments. These inbreds and hybrids will also be tested in the other Mandaamin, Rutgers and Johnston-Monje trials.Seed from selected inbred lines will be evaluated for root hair, bacterial load, and N efficiency before planting. Soils samples will be analyzed by Cornell University's Soil Health Lab. Soil protein samples will be analyzed for δ15N. In September residual nitrate in the top two feet of soil will be determined. Roots, stover, and grain will be harvested at the end of the season, weighed, dried, and analyzed for N isotope ratios.The inbreds and hybrids will be scored for relative vigor, plant height, number of leaves, hairiness of leaf sheaths and leaves, flowering date, anthesis-silking interval, and grain yield and moisture. Root monoliths will be excavated and number of root tips and branches, root length and necrosis will be determined to estimate root length and health.Roots, stover (stalks, tassels, leaves), and grain will also be harvested, dried, and weighed at harvest to determine dry matter partitioning and mineral content, total N and mineral uptake and natural abundance estimates of N2 fixation. Grain samples will be evaluated using NIR spectroscopy to predict protein, oil, starch, density, and methionine, cysteine, and lysine content in whole grain. Ten samples each year will be analyzed for carotenoids using HPLC.Data will be gathered, variances and means will be calculated and compared using spreadsheets and JMP statistical programs. Models will be constructed to account for variation in crop performance associated with soil and pre-plant scoring parameters and microbial assays from Rutgers and Max Planck Institute.Research on plant/microbiome N-fixation partnerships and rhizophagy by Rutgers University and David Johnston-Monje. Seed of the same set of 20 inbreds and hybrids tested by the Mandaamin Institute, will be examined at both institutions.At Rutgers the nitrogen-transfer activity of endophytes in roots, stems, cob leaves, leaf sheaths (including trichomes and other non-photosynthetic cells) will be evaluated using light and confocal microscopy. Enriched 15N atmospheres will quantify N fixation and in which organs it occurs. Isolated bacteria (Monje lab) will be tagged with the mCherry gene, then inoculated in corn. Bacteria will be visualized within corn cells in roots, leaf sheaths, leaf blades, stems and husk leaves. Corn seedlings will be inoculated with isolated N-fixing bacterial endophytes--then assessed for 15N absorption in inoculated and non-inoculated plants to confirm that bacteria isolated were responsible for N2-fixation.Rhizophagy, roots will be scored as mentioned above.Experiments will suppress plant rhizophagy and compare results with unsuppressed plants for nutrient absorption..David Monje will study seed borne, nitrogen fixing microbiomes and whether there are contrasting patterns as they colonize the organs and rhizosphere of the plant. In the first year, plants will be grown in sterile sand fertigated with N free solution. In the second year 6 inbreds will be grown on an agricultural soil as: a) seed from the same lot that was tested in Colombia the first year; b) seed that was grown from the same lot in Mandaamin Institute trials on a un-manured plot in WI; and c) seed from that same inbred grown on a manured plot side by side with b.Plants will be sequentially sampled to check for transmission of bacteria to the next generation. Harvested plants will be separated into rhizosphere, root, shoot, and seed. DNA will be isolated, the bacterial 16S will be amplified and sequenced to profile the taxonomy of endophyte bacteria. Cultured endophytes will be screened for N on N free media, Nif genes will be amplified used to identify bacteria. Candidate strains will be inoculated into sterile plants and evaluated for their ability to restore the N fixation trait.On-farm research. For varietal trials, 5 hybrids will be planted out in two or three replicated randomized blocks on each 4 farms. Variety x manuring trials will be carried out on 6 farm sites each year. The best- Mandaamin hybrid will be compared with a commercial hybrid. Farmers will grow these cultivars in strips plots across an organic manure treatment, with three replicates on each farm. Manuring practices may include with and without cover crops, timing of planting after green manures, type and placement of animal manure or compost in the crop rotation before growing corn. Mandaamin Institute will collect and analyze soil, plant, and yield samples as described in the attached SARE report. We will document specific practices on each farm, and work with them to describe and estimate their costs and net profitability. Soils, roots, stover, and grain from the project will gathered, and analyzed as mentioned above.

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:Organic farmers, organic seed company employees, researchers concerned with endophytes and with corn, intern, staff of the Mandaamin Institute, graduate student. Changes/Problems:Feedback from farmers, seed companies, and scientists is that 1) we should focus more effort on proving whether or not nitrogen fixation is occurring in the Mandaamin plants and put less emphasis on other details of the research; 2) we should produce seed of our best inbreds and hybrids for larger scale testing. As described above, we took steps to bring our inbreds and produce hybrids to address the needs of on-farm testing. However, it did not prove possible to begin testing with farmers in 2023 due to the lack of hybrid seed. Our cooperating company, Foundation Direct Seed, sold out its seed stocks of our hybrids and there was little to work with. They also ceased producing organic seed. Thus we focussed on producing hybrid seed ourselves in 2023 for trials with farmers and manuring in 2024. Another obstacle was that David Johnston Monje, our microbiology cooperator, and a re-known World expert on corn endophytes, lost his position at Valley University in Colombia. We were able to move forward with him on an abbreviated plan and actions to identify microbial partners in 19 different inbreds and to start in analysis of nif genes. However, we had to curtail his participation in clarifying manuring effects. On the other hand, new microscopic and fatty acid data from last year's work suggest that the Mandaamin plants are fostering the accumulation of a much larger internal biome consisting in more gram negative bacteria, fungi, and protozoa; b) that considerable bacterial necromass is accumulating in specific tissues of the Mandaamin maize; and c) that isotope partitioning may be occuring in different tissues of the maize. All this makes interpretation of natural abundance studies more complex. Dr. White will continue his studies next year with 15N enriched atmospheres. However, we are presently seeking alternative ways of satisfying our plan for analyzing microbial communities and nitrogen fixation with another microbiologist; possibly by quantifying nitrogenase production for Mandaamin and conventional varieties. What opportunities for training and professional development has the project provided?A technician, a student intern, and a graduate student learned about maize endophytes and about microscopy technique pertinent to examination of field and pot grown maize plants for examining endophytic relationships with bacteria. This included the use of histological stains. The new technician and the intern learned maize breeding philosophy and methods including selection, pollination, harvesting, seed treatment, learning to read phenotypes, etc. Two of the scientists on the project learned more about where and how endophytic colonization is occurring in different maize cultivars, including Mandaamin and conventional inbreds. Ward labs and those scientists learned about utilizing fatty acid analysis to quantify endophytes in maize leaves. How have the results been disseminated to communities of interest?Outreach: This first consisted in a field day at the Hughes Farm near Janesville in September showing corn grown organically without fertilization in two 20 acre blocks next to conventional corn. The Field day occurred in conjunction with Marbleseed and the University of Wisconsin organic advisory services and approximately 90 people, mostly farmers were present. The Mandaamin hybrid looked good and mineral analysis and chlorophyll measurements showed it had been more efficient at obtaining N than commercial hybrids grown in neighboring blocks. Consequently, the PD wrote an article on nitrogen fixing corn for the Organic Broadcaster which was subsequently published in ACRES USA, thereby reaching a wide spectrum of organic farmers. This was followed up by 1) a poster showing our results at the Marbleseed Conference in LaCrosse in February which was displayed at the conference in front of the Foundation Seed Direct booth in the commercial section; and 2) an interview with the PD which appeared in MadAgriculture, a magazine for sustainable farming on N efficiency and endophytes. Attendence at the Marbleseed conference allowed for interaction with farmers about endophyte containing corn and nitrogen. Discussions were held with feed and seed company personnel. The PD outlined the results of the breeding program with endophytes obtained so far in a publication by the Journal for Agriculture, Food Systems, and Community Development. The article is called: "The evolution of a partnership-based breeding program for organic corn," Other outreach during this period consisted in several scientific publications written by James White and Walter Goldstein which documented results with endophytes gained from research on the corn. The titles of these publications is documented in this report in preceding sections. The research covered endophytes found in our corn seedlings and their transfer to other cultivars as well as general implications for understanding host/endophyte relationships. What do you plan to do during the next reporting period to accomplish the goals?Progress was made breeding for plant partnerships, determining what the endophytes are, what they do in different parts of the plants. Results show that the Mandaamin inbreds are fostering microbial biomass and microscopy showed microbial necromass especially in convoluted cell possessing tissues in the epidermis and in seed bracts. We assume plants are generating N from microbial biomass and necromass, and not exclusively from soil provided nitrate and ammonium. We intend to focus on clarifying fixation and where it is occuring through 15N lab studies and studies of nif gene expression. We intend to learn more about how manuring affects microbial performance in plants. .We are planning to conduct several studies in future experiments as follows. Mandaamin institute will continue breeding and testing activities on small plots to focus emphasis on the most commercially competitive, N efficient, nutritious cultivars as in the first year of work. Seed of the most promising inbreds and hybrids will be produced. In addition we will distribute seed of hybrids to cooperating organic farmers and work with them to test them with conventional checks on their farms. This will hopefully include some studies with and without application of animal manures. Effects of manuring will be quantified by yields and mineral uptake, and tested with microscopic and isotopic examination of tissues. The results of this work should help us to interface with companies and farmers to start associative testing efforts on a larger scale Objectives of the White lab include: We will use isotopic nitrogen tracking to identify locations in plants where nitrogen is being fixed and accumulating. We will evaluate internal colonization of chloroplasts by endophytic bacteria and its role in the 'stay green' phenomenon through use of confocal microscopy. We will isolate specific microbes from the corn endophyte community and test the effects of individual microbes on replicating nitrogen fixation in plants--and on chloroplast durability and the 'stay green' effect. We will explore/document microbial effects on genetic variability of the corn genome. Endophytic bacteria within pollen mother cells secrete ethylene and nitrate. These microbe-produced substances are known to trigger chromosome replication in plants--and during replication transposons and other genetic elements may increase variation in the pollen genomes--resulting in greater genetic variability in the highly microbial corn selections.

Impacts
What was accomplished under these goals? Report from Walter Goldstein (Mandaamin Institute). 1) Characterizing endophytic colonization in cultivars: We studied colonization of seedlings by seed-borne endophytes by germinating seed in Petrie dishes, sectioning their tissues, and examining them with microscopy under supervision from Dr. White. In the seedling tissues bacteria appearedto be released from nuclei in excreted vesicles, which confirmed results published by Dr. White's team at Rutgers. In multiple cases we observed bacteria apparently penetrating into nuclear sheaths and exiting them. We developed a seedling test for examining and measuring root hair length which was associated with microbial colonization/hormonal production. This included a survey of root hair production by numerous Mandaamin inbreds and conventional inbreds. Mandaamin inbreds (especially the most N efficient inbreds) consistently had more root hairs than conventional inbreds and repeated trials with Mandaamin inbred C4-6 showed they expanded the active diameter of roots by approximately one third. Microbial activity and diversity seemed most apparent intracellularly in root cap cells which break off from the root apex and produce innoculated mucoidal substances that lubricate root growth and create soil-root bonds. Bacteria were observed intracellularly, in periplasmic spaces, and streaming intracellularly and between cells. We surveyed numerous field-grown Mandaamin and conventional inbreds for colonization by microbes. Results were recorded in films and photographs. For Mandaamin inbreds, nitrate-secreting bacteria are living in vascular tissues, in the profuse hairs in our cultivars, in epidermal cells in leaves and husks, on the surfaces of chloroplasts, in seed bracts, and in reproductive tissues such as cob bracts, silks, pollen, and embryos. Trichomes, convoluted epidermal cells in epidermis, areas surrounding chloroplasts, and the seed bracts of the cultivars harbored colonies of bacteria that stained for nitrate production. Differences in colonization of chloroplasts between Mandaamin and conventional inbreds were especially profound. The most N efficient Mandaamin inbreds showed colonization of both bundle sheath and mesophyll chloroplasts. Different inbreds were rated for the percent of chloroplasts colonized by bacteria based on multiple films of leaf structure. Inbreds bred under conventional conditions generally had very low bacterial colonization while the most N efficient inbreds had scores between one third to three fourths of chloroplasts colonized. 2) Multiplying pertinent inbreds and producing hybrids: A new organically managed winter nursery was established in Chile with 660 rows. Inspection there showed that evolution and selection are causing convergent phenotypes in Mandaamin breeding families from widely different genetic backgrounds. Mandaamin inbreds tend to possess profuse root hairs and branched rooting systems in the topsoil, pilose leaves and leaf sheaths, and thick, folded and buckled leaves with high chlorophyll contents. Hybrid seed produced in Chile and in Wisconsin was grown out in replicated yield trials in the East Troy area on 9 acres of plots. Plot weediness was qualitatively rated. Hybrid production and seed multiplication took place on 2.5 acres on the Zinniker organic/biodynamic farm and 1 acre on the Goldstein organic farm. On these farms multiple hybrids were produced with two different N efficient/N fixing male testers. Furthermore, we advanced inbreds through hand pollination on a 2.5 acre nursery on the Zinniker farm. A set of N efficient Mandaamin inbreds and conventional inbreds from adjacent rows in that nursery were utilized for comparisons. Mandaamin inbreds had greater root and grain production, greater microbial biomass in leaves, and more tassel branching. Leaf and root samples were tested for microbial biomass in conjunction with Ward Labs. Root samples were frozen for further investigative work. 3) Testing new knowledge by selecting plants for N efficiency. We grew a set of N efficient inbreds on a field that had been cropped two years with corn without fertilizer. We visually selected plants for N efficiency based on new insights gained on linkages between plant phenotype and bacterial colonization. Young plants that were identified to have the N efficient/bacterial colonization phenotype were marked before flowering and later they were intermated. In the Fall all plants were measured and flowering date, chlorophyll content in leaves, and brace root scores were recorded. The plants that were visually chosen to be N efficient had earlier flowering dates, higher chlorophyll scores in September, and greater brace root scores than the other plants. Report from David Johnston Monje on identifying endophytes. Nineteen N efficient maize inbreds were grown to seedlings in pots. 256 bacterial endophytes were extracted from leaves and roots of plants that were grown in sterile soil. DNA was extracted from shoot and root tissues of 63 plants grown on sterile soil, plus 63 plants grown on normal soil. DNA was extracted from 21 sterilely grown root tips and from another 21 root epidermal peels. Subsequently 16S rDNA was amplified from all the bacterial stainsand will soon be sent in for sequencingso that we can know the taxonomy of the isolates. The isolates are being tested for nifH with PCR on the isolates. Testing the primers on the first 96 strains, got 0 hits, so we are working to optimize the reaction to work better (a positive control did work). NifH PCRs will be run on all the bacterial isolates once the PCR reaction is optimized; 16S and nifH PCRs will be run on all the DNA extracts, and the resulting samples will be sent for sequence analysis. Report from James White (Rutgers) on differences between N efficient and conventional inbreds: Leaf epidermal cells and trichomes, as well as root hairs were larger in highly microbial colonized corn cultivars (e.g., Mandaamin selection C4-6), compared to commercial cultivars. This increased cell growth was attributed to hormonal effects of endophytic bacterium-produced ethylene and nitrate within plant cells that serve as plant growth stimulants. We determined that C4-6 showed abundant bacteria within leaves, and that these bacteria were evident in the vascular bundle sheath cells around and within the bundle sheath chloroplasts. Chloroplasts in C4-6 tended to remain green and functioned better under conditions of low nitrogen application compared to commercial cultivars. In commercial cultivars chloroplasts tended to degrade in older leaves under low nitrogen conditions resulting in chlorosis in older leaves as nutrients are removed from older leaves to fuel growth in younger leaves. Preservation of chloroplasts in C4-6 resulted in more consistent photosynthesis. Through collaboration with Ward Labs, Inc, fatty acid analysis of Mandaamin and commercial cultivars showed that microbial-rich Mandaamin inbreds contained significantly more bacterial biomass and it was predominantly gram-negative. We developed methods to move endophytic bacteria from highly microbial plants into plants lacking microbes. Leaves were triturated to extract endophytic microbes. Seedlings germinating in the microbial extracts absorbed the bacteria into their tissues as they germinated. We demonstrated that bacteria from C4-6 were capable of nitrogen-fixation in the test seedlings of lettuce, sorghum and creeping bluegrass based on use of histochemical stains to detect nitrate in seedling tissues. Transference of the endophytic bacteria from C4-6 into creeping bluegrass (Poa reptans) resulted in the 'stay green' feature seen in C4-6 and it was also associated with bacterial colonization of chloroplasts in leaves. We hypothesize that nitrogen delivery to the chloroplasts by endophytic bacteria protracts survival of functioning chloroplasts.

Publications

• Type: Journal Articles Status: Published Year Published: 2023 Citation: X. Chang, B. Young, N. Vaccaro, R. Strickland, W. Goldstein, L. Struwe, & J.F. White. 2023. Endophyte symbiosis: evolutionary development, and impacts of plant agriculture. Grass Research 3, Article number: 18 (2023). https://www.maxapress.com/article/doi/10.48130/GR-2023-0018.
• Type: Journal Articles Status: Published Year Published: 2023 Citation: Goldstein, W.A. The evolution of a partnership-based breeding program for organic corn. 2023. Refereed journal article accepted for fall publication in the Journal of Agriculture, Food Systems, and Community Development. https://doi.org/10.5304/jafscd.2023.131.011
• Type: Book Chapters Status: Awaiting Publication Year Published: 2023 Citation: J.F. White and W.A. Goldstein. The rhizophagy cycle in roots and nitrogen-transfer endosymbiosis in plant hairs are fundamental processes for sustainable plant cultivation. Book title: Microbioma: One-Health: Dal Suolo la Benessere Umano
• Type: Websites Status: Published Year Published: 2023 Citation: Walter Goldstein, Juan E. Andrade Laborde, Pierre Meyer, Ece Gulkirpik. M. Toc. 2023. Testing the quality of corn that has been selected for organic poultry. eOrganic publications. https://eorganic.org/node/35728
• Type: Journal Articles Status: Published Year Published: 2022 Citation: W. Goldstein. 2022. article titled: Nitrogen Fixing Corn. Organic Broadcaster, Sept 20, 2022 https://issuu.com/marbleseed.
• Type: Journal Articles Status: Published Year Published: 2023 Citation: W.A. Goldstein. 2023. Nitrogen fixing corn. ACRES USA; January, 2023. https://bookstore.acresusa.com/products/january-2023-issue.