Maize (Zea mays L.) is the world's most productive grain crop and a cornerstone of global food supply. However, in temperate agricultural systems, maize exhibits 2 key anomalies. First, as a tropical species, maize cannot be planted in the cold conditions of early spring when light and natural soil nitrogen are available, resulting in a shorter growing season and creating a seasonal mismatch between nitrogen accessibility and demand. Second, maize kernel protein is a major nitrogen sink, driving fertilizer demand because of the scale of cultivation. This inefficient mismatch stems from modern maize's uses and the modest nutritional value of storage proteins. To address these anomalies, we established the Circular Economy that Reimagines Corn Agriculture initiative. Our vision requires advances in 3 research areas: (ⅰ) developing cold and frost tolerance during germination and early growth to enable the use of spring nitrogen and light resources; (ⅱ) reducing nitrogen allocation to grain by reducing low-quality storage proteins and developing alternative nitrogen sinks; and (ⅲ) stabilizing soil nitrogen by enhancing biological nitrification inhibition. We present blueprints for a nitrogen-efficient, cold-tolerant maize designed to utilize the full growing season, enabling farmers in temperate regions to fully leverage maize's C4 photosynthesis, reduce fertilizer inputs, increase yields, and minimize environmental impact.

The wide-and narrow-row cropping technology used for maize has the advantages of protecting cultivated soil and improving the population structure in maize fields. However, the relationship between nitrogen application position and root interactions has not been determined. Through pot and field experiments, we evaluated the effects of two nitrogen application positions ((narrow row nitrogen application (RC) and wide row nitrogen application (RN)) and two nitrogen application regimens ((high nitrogen(HN) and low nitrogen(LN)) on root growth and yield composition of wide-narrow row maize during the flowering and harvest stages. In field experiments, RC increased the biomass, length and surface area of competing roots (narrow-row roots, CR) at the flowering stage. The yield and agronomic efficiency of N(AEN) and partial factor productivity of N(PFPN) were increased by RN compared to RC under HN, However, the AEN under LN was significantly lower; There was no significant effect on maize growth and biomass allocation at the same level of application of N. At the flowering stage, the results of CR and non-competing roots (wide-row roots, NCR) was consistent under pot experiments and the field experiments, and the yield under RN was also higher than that under RC, although the difference was not significant. Furthermore, according to the principal component analysis and correlation analysis, the competing roots were the main factor influencing yield and AEN. In conclusion, our study showed that RN is a useful fertilization method to improve overall productivity. All in all, how roots coordinate neighbors and nitrogen spatial heterogeneity is a complex ecological process, and its trophic behavior deserves further study.

Cutting is a crucial agricultural practice,and its impact on potato growth varies depending on the extent of the cut.A randomized complete block design was employed in an experiment to explore the impact of cutting timing,frequency,and cutting height on potato yield and tuber size distribution.It was found that a single cutting at the late seedling stage or tuber formation stage,with a cutting intensity at 1/3 or 1/4 of the plant height,had no significant impact on potato yield.However,conducting two cuttings during the late seedling stage and tuber formation stage resulted in a significant reduction in potato yield.The cutting treatment substantially increased the number of small tubers(<50 g).Compared to the control group(CK,conventional cultivation),the tuber number per plant was significantly increased in 20-50 g,when 1/3 of the plant was cut during tuber formation.Except for two treatments,which involved cutting 1/4 of the plant once at the late seedling stage or plus cutting 1/4 of the plant at the tuber formation again,the remaining six cutting treatments all significantly increased the tuber number per plant in<20 g.A single cut at the late seedling stage or tuber formation stage did not result in a significant difference in above ground biomass per plant compared to the CK,indicating a compensatory effect of appropriate cutting during the early growth stage of potatoes.In conclusion,a single cut at the late seedling stage or tuber formation stage does not impact potato yield but could increase the number and weight of small tubers,which is advantageous for seed potato production.

Planting cotton (Gossypium hirutum L.) into small grain residues could reduce weeds through allelopathy but evidence also suggests suppression of cotton. Four greenhouse studies with four replicates each investigated allelopathic effects of ‘Lockett’ wheat (Triticum aestivum L.), ‘Maton’ rye (Secale cereale L.) and 2-2-benzoxazolinone (BOA), on ‘FiberMax 9058F’ cotton. Experiments were 1) Cotton planted into Pullman clay loam with 0, 800, 1600, 3200, 6400, and 12,800 kg ha-1 dried ground rye or BOA at 0, 500, 1000 nmol g-1 soil; 2) Experiment 1 with no cotton planted; 3) Cotton planted into Experiment 2 soil after 312 d; 4) cotton planted into soil with rye or wheat at 0, 6400, 12800 kg ha-1 or BOA at 0, 500, 1000 nmol g-1 soil. Germination, plant height, weight, and leaf chlorophyll (Experiments 3 and 4), of cotton were determined 28 d (Experiment 1), 364 d (Experiment 3), and 52 d (Experiment 4) post-treatment application. Added BOA reduced germination and plant heights (Experiments 1 and 4) but not when cotton was planted 312 d post BOA application (Experiment 3). Rye (Experiments 1, 3, and 4) and wheat (Experiment 4) decreased cotton seedling heights in all experiments and chlorophyll in Experiments 3 and 4. Known allelopathic chemicals were identified in soils and appeared related to effects on cotton seedlings. Results strengthen conclusions that allelopathy from wheat or rye can reduce plant growth and yield of cotton and effects in soils can persist up to 12 months.

Small grain cover crops offer grazing opportunities but effects on following row crops are not well understood. From 1999 through 2008, stocker steers (Bos taurus) grazed small grains in a two‐paddock crop rotation of rye (Secale cereale L.), cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.), fallow, and rye. Treatments in 2005, 2007, and 2008 included (i) zero‐grazed rye from 1999; (ii) ungrazed rye in the current year only; (iii) always grazed rye; and (iv) in 2007 and 2008, monoculture cotton (since 1999) with no cover crop. The experiment, on a Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustolls), was a randomized complete block design with three blocks. Ungrazed rye was mechanically harvested before planting cotton. Rye excluded from grazing in 1 yr only (Treatment 2) was taller (P < 0.05) and produced more forage mass than zero‐grazed rye (Treatment 1), likely due to higher rye tiller numbers, weight, and basal cover. Cotton planted into grazed rye had more plants m–1 row and was taller until July (P < 0.05), and in 2005 had greater (P < 0.05) lint and seed yield than where grazing was excluded. Continuous cotton with no cover crop (Treatment 4) was shorter (P < 0.01) than cotton grown with a cover crop regardless of grazing. Known allelopathic chemicals were detected in rye and soil where rye grew and appeared to be influenced by grazing. Increased growth and productivity of rye and cotton where grazing occurred may be related to suppressive effects of grazing on allelopathy.

No-till planting cotton (Gossypium hirsutum L.) into small grain cover crops has many benefits including allelopathic suppression of weeds but potential to also suppress cotton has been suggested. We investigated effects of rye (Secale cereal L.), wheat (Triticum aestivum L.), or no cover crop on no-till planted cotton in a 3-yr field-plot experiment (randomized block design; 4 blocks), conducted at the Texas Tech Field Laboratory, New Deal. Soil was Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustolls). From 2007 to 2009, wheat or rye was planted into one-half of each replicate plot each September. Growth, removed in May, was chemically terminated with glyphosate. Cultivar FiberMax 9058F cotton was no-till planted each May and was harvested by December. By the end of the growing season, cotton planted with no cover crop was taller (P < 0.05) than cotton planted into cover crops. Cotton lint and seed yield were reduced (P < 0.05) by cover crops but the magnitude of the effects differed each year. Cotton leaf chlorophyll, measured in September 2009, was greater (P < 0.05) when no cover crop was used than for cotton planted into cover crops. Higher (P < 0.05) concentrations of three allelochemicals [2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA); 2,4-dihydroxy-(2H) -1,4-benzoxazin-3 (4H)-one (DIBOA); 2-benzoxazolinone (BOA)] were detected in soils where cover crops grew than where no cover crops were used but amounts varied due to specific cover crop and sampling date. Results suggest that lower cotton growth and yield due to cover crop may be partly due to their release of allelochemicals.

specific objectives of this proposal were to: 1) determine the location, topology, and oligomerization of FtsH11 protease; 2) identify the substrate/s of FtsH11 and the downstream components involved in maintaining thermostability of chloroplasts; 3) identify new elements involved in FtsH11 protease regulatory network related to HT adaptation processes in chloroplast; 4) Study the role of FtsH11 homologs from crop species in HT tolerance. Background to the topic: HT-tolerant varieties that maintain high photosynthetic efficiency at HT, and cope better with daily and seasonal temperature fluctuations are in great need to alleviate the effect of global warming on food production. Photosynthesis is a very complex process requiring accurate coordination of many complex systems and constant adjustments to the changing environments. Proteolytic activities mediated by various proteases in chloroplast are essential part of this process and critical for maintaining normal chloroplast functions under HT. However, little is known about mechanisms that contribute to adaptation of photosynthetic processes to HT. Our study has shown that a chloroplast-targeted Arabidopsis FtsH11 protease plays an essential and specific role in maintaining thermostability of thylakoids and normal photosynthesis at moderate HT. We hypothesized that FtsH11 homologs recently identified in other plant species might have roles similarly to that of AtFtsH1. Thus, dissecting the underlying mechanisms of FtsH11 in the adaptation mechanisms in chloroplasts to HT stress and other elements involved will aid our effort to produce more agricultural products in less favorable environments. Major conclusions, solutions, achievements - Identified the chloroplast inner envelope membrane localization of FtsH11. - Revealed a specific association of FtsH11 with the a and b subunits of CPN60. - Identified the involvement of ARC6, a protein coordinates chloroplast division machineries in plants, in FtsH11 mediated HT adaptation process in chloroplast. -Reveal possible association of a polyribonucleotide nucleotidyltransferase (cpPNPase), coded by At3G03710, with FtsH11 mediated HT adaptation process in chloroplast. - Mapped 4 additional loci in FtsH11 mediated HT adaptation network in chloroplast. - Demonstrated importance of the proteolytic activity of FtsH11 for thermotolerance, in addition to the ATPase activity. - Demonstrated a conserved role of plant FtsH11 proteases in chloroplast biogenesis and in maintaining structural and functional thermostability of chloroplast at elevated temperatures. Implications, both scientific and agricultural:Three different components interacting with FtsH11 were identified during the course of this study. At present, it is not known whether these proteins are directly involved in FtsH11mediated thermotolerance network in chloroplast and/or how these elements are interrelated. Studies aiming to connect the dot among biological functions of these networks are underway in both labs. Nevertheless, in bacteria where it was first studied, FtsH functions in heat shock response by regulating transcription level of σ32, a heat chock factor regulates HSPsexpression. FtsH also involves in control of biosynthesis of membrane components and quality control of membrane proteins etc. In plants, both Arc 6 and CPN60 identified in this study are essential in chloroplast division and developments as mutation of either one impairs chloroplast division in Arabidopsis. The facts that we have found the specific association of both α and β CPN60 with FtsH11 protein biochemically, the suppression/ enhancement of ftsh11 thermosensitive phenotype by arc6 /pnp allele genetically, implicate inter-connection of these networks via FtsH11 mediated network(s) in regulating the dynamic adaptation processes of chloroplast to temperature increases at transcriptional, translational and post-translational levels. The conserved role of FtsH11 proteases in maintaining thermostability of chloroplast at HT demonstrated here provides a foundation for improving crop photosynthetic performance at high temperatures.

Drought and high temperature are two major environmental factors that severely limit plant productivity in the United States and worldwide, often causing extensive economic loss to agriculture. As global climate change progresses, agricultural production worldwide faces serious threats from frequent extreme weather conditions. Integrated approaches that improve the efficiency of agricultural water use and development of plant varieties that can alleviate the negative impacts of environmental stresses to maintain yield stability are essential to sustain and increase agriculture production. Maize (Zea mays L.) is a major crop in the United States and worldwide. Its production and yield stability are greatly affected by drought and high temperature stresses. Improving drought and heat tolerance in maize has become one of the top priorities for maize breeding programs in both private and public sectors. Identification of maize germplasm with superior drought and/or heat tolerance is essential and prerequisite for such propose. In this report, we evaluated a selection of maize inbred lines for drought and heat stress tolerance under field conditions in 2009 and 2010 and identified several inbred lines that showed high tolerance to drought. Tolerant inbred lines (Tx205, C2A554-4, and B76) were able to maintain relatively high leaf relative water content when subjected to drought stress, while sensitive lines (B73 and C273A) showed a rapid reduction in leaf relative water content at very early stage of drought. The tolerant lines also showed significantly greater ability to maintain vegetative growth and alleviate damage to reproductive tissues under drought conditions compared to the sensitive lines. Maize inbred lines and hybrids were also evaluated for tolerance to high temperature under well-watered conditions through field observations following the occurrence of major heat events. Maize inbred lines of distinct heat tolerance phenotype were identified. Furthermore, genetic and phenotypic analysis showed that maize hybrids made from inbred lines with superior heat tolerance inherited an enhanced tolerance to elevated temperatures. The tolerant germplasm accessions, like those identified in this study, are essential materials for breeding drought- and/or heat-tolerant maize hybrids. Study for the potential use of such materials to produce maize hybrids that are able to alleviate the negative impacts of drought and heat stress on the growth and development of maize plants is underway.

In the course of map-based cloning of the barley stem rust resistance gene Rpg1, we identified a rice bacterial artificial chromosome (BAC) containing the Rpg1 flanking markers. Based on the excellent gene order colinearity between barley and rice in this region, we expected that this rice BAC would contain the barley Rpg1 homologue. In order to identify the putative rice homologue, we sequenced ca. 35 kb of the rice BAC at random and then an additional 33 kb of contiguous sequence between the two most closely spaced Rpg1 flanking markers. Sequence analysis revealed a total of 15 putative genes, 5 within the 33-kb contiguous region. A rice Rpg1 homologue was not identified, although a gene encoding a hypothetical polypeptide with similarity to a membrane protein could not be eliminated as a candidate. Surprisingly, four of the genes identified in the 33-kb contiguous rice sequence showed a high degree of similarity with genes on Arabidopsis chromosome 4. The genome regions harboring these genes showed some relatedness, but many rearrangements were also evident. These data suggest that some genes have remained linked even over the long evolutionary separation of Arabidopsis and rice, as has also been reported for mammals and invertebrates.

Fifteen corn kernel and corn screening samples were analyzed for the presence of fumonisin toxins. Samples were extracted with acetonitrile/water (1:1) and cleaned up with C-18 solid phase extraction (SPE) cartridges. Analysis of fumonisins was carried out by on-line capillary liquid chromatography-fast atom bombardment mass spectrometry (capillary LC/FAB/MS). Two isomers of partially hydrolyzed fumonisin B-1 (PHFB1) were detected in five samples, and N-acetyl fumonisin B-2 (FA(2)) was detected in one sample. Hydrolyzed fumonisin B-1 (HFB1) was also detected in one sample, but further confirmation is needed.

Cultures of Fusarium moniliforme and Alternaria alternata f. sp. lycopersici were grown in the laboratory and analyzed for various fumonisin derivatives. Analyses were made by continuous flow fast atom bombardment and ionspray mass spectrometry interfaced to microcapillary HPLC. Besides FB1, FB2 and FB3 derivatives, two isomers of the one-armed FB1 (protonated molecular ion at m/z 564) and two isomers of the one-armed FB2 (m/z 548) were found. Two different isolates of A. alternata when grown in culture yielded FB1, FB2 and FB3. One of them also yielded the one-armed FB1 which was identical to that metabolite found in Fusarium and naturally infected corn. FB1, FB2 and FB3 have been found in 2 different isolates of Alternaria alternata, both obtained from tomato.

Fumonisin B1 (FB1) was isolated from samples of forage grass originating in paddocks associated with an idiopathic disease of Canadian wapiti and wapiti-red deer hybrids characterized by "ill thrift" and liver dysfunction. Four of 40 samples contained 1, 3, 6, and 9 ppm (micrograms per gram) of FB1 and 4, 0.5, 2, and 0.5 ppm, respectively, of the methyl ester of FB1. Analyses were done by ion spray mass spectrometry and confirmed by both fast atom bombardment (solids probe) and mass spectral analysis by electron impact ionization of the trifluoroacetate derivative of the base hydrolyzed product (pentolamine) of FB1. This article contains the first report of the presence of fumonisin B1 in grass.

The mycotoxin fumonisin B 1 , originally described as being produced by Fusarium moniliforme , was detected in liquid cultures of Alternaria alternata f. sp. lycopersici , a host-specific pathogen of tomato plants. The metabolite was detected by high-pressure liquid chromatography and mass spectrometry. Its identity was confirmed by fast atom bombardment and ion spray mass spectrometry, as well as parent-daughter tandem mass spectrometry. In three separate experiments, the concentrations found ranged between 5 and 140 ppm (μg/ml).

This report extends research on Al-induced changes in membrane behavior of intact root cortex cells of Northern red oak (Quercus rubra). Membrane permeability was determined by the plasmometric method for individual intact cells at temperatures from 2 or 4 to 35 degrees C. Al (0.37 millimolar) significantly increased membrane permeability to urea and monoethyl urea and decreased permeability to water. Al significantly altered the activation energy required to transport water (+32%), urea (+9%), and monoethyl urea (-7%) across cell membranes. Above 9 degrees C, Al increased the lipid partiality of the cell membranes; below 7 degrees C, Al decreased it. Al narrowed by 6 degrees C the temperature range over which plasmolysis occurred without membrane damage. These changes in membrane behavior are explainable if Al reduces membrane lipid fluidity and kink frequency and increases packing density and the occurrence of straight lipid chains.