Response Of Maize Research Articles

A Maize Calmodulin-like 3 Gene Positively Regulates Drought Tolerance in Maize and Arabidopsis

Drought stress is one of the important abiotic stresses that affects maize production. As an important Ca2+ sensor, calmodulin-like proteins (CMLs) play key roles in plant growth, development, and stress response, but there are a limited number of studies regarding CMLs in response to drought stress. In this study, a Calmodulin-like gene, namely ZmCML3, was isolated from maize (Zea mays L.). The coding sequence (CDS) of ZmCML3 was 474 bp and a protein of 158 aa which contains three EF-hand motifs. ZmCML3 was localized within the nucleus and plasma membrane. The expression of ZmCML3 was induced by polyethylene glycol (PEG) 6000, NaCl, methyl jasmonate (MeJA), and abscisic acid (ABA). Overexpression of ZmCML3 resulted in enhanced drought tolerance in maize through increasing proline (Pro) content and the activity of peroxide (POD) and superoxide dismutase (SOD). Meanwhile, ZmCML3 also positively regulated the expression of drought stress-responsive genes in maize under drought stress treatment. Taken together, ZmCML3 acts as a positive regulator in maize response to drought stress. These results will provide theoretical basis for breeding drought tolerance maize variety.

Toll/interleukin-1 receptor-only genes contribute to immune responses in maize.

Proteins with Toll/interleukin-1 receptor (TIR) domains are widely distributed in both prokaryotes and eukaryotes, serving as essential components of immune signaling. Although monocots lack the major TIR-nucleotide-binding (NB)-leucine-rich repeat (LRR)-type (TNL) immune receptors, they possess a small number of TIR-only proteins, the function of which remains largely unknown. In the monocot maize (Zea mays), there are three conserved TIR-only genes in the reference genome, namely ZmTIR1 to ZmTIR3. A genome-wide scan for TIR genes and comparative analysis revealed that these genes exhibit low sequence diversity and do not show copy number variation among 26 diverse inbred lines. ZmTIR1 and ZmTIR3, but not ZmTIR2, specifically trigger cell death and defense gene expression when overexpressed in Nicotiana benthamiana leaves. These responses depend on the critical glutamic acid and cysteine residues predicted to be essential for TIR-mediated NADase and 2',3'-cAMP/cGMP synthetase activity, respectively, as well as the key TIR downstream regulator Enhanced Disease Susceptibility 1 (EDS1). Overexpression of ZmTIR3 in N. benthamiana produces signaling molecules, including 2'cADPR, 2',3'-cAMP and 2',3'-cGMP, a process that requires the enzymatic glutamic acid and cysteine residues of ZmTIR3. ZmTIR expression in maize is barely detectable under normal conditions, but is substantially induced by different pathogens. Importantly, the maize Zmtir3 knockout mutant exhibits enhanced susceptibility to the fungal pathogen Cochliobolus heterostrophus, highlighting the role of ZmTIR3 in maize immunity. Overall, our results unveil the function of the maize ZmTIRs. We propose that the pathogen-inducible ZmTIRs play an important role in maize immunity, likely through their enzymatic activity and via EDS1-mediated signaling.

Analysis of the Transcriptome Provides Insights into the Photosynthate of Maize Response to Salt Stress by 5-Aminolevulinic Acid.

Salt stress is a significant environmental factor that impedes maize growth and yield. Exogenous 5-aminolevulinic acid (ALA) has been shown to mitigate the detrimental effects of various environmental stresses on plants. However, its regulatory role in the photosynthesis mechanisms of maize seedlings under salt stress remains poorly understood. Transcriptome sequencing and physiological index measurements were conducted on the leaves of the "Zhengdan 958" cultivar subjected to three different treatments. Differential expression analysis revealed 4634 differentially expressed genes (DEGs), including key transcription factor (TF) families such as NAC, MYB, WRKY, and MYB-related, across two comparisons (SS_vs_CK and ALA_SS_vs_SS). Significant enrichment was observed in the metabolic pathways related to porphyrin metabolism, photosynthesis-antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. ALA treatment modulated the expression of photosynthesis-related genes, increased photosynthetic pigment content, and enhanced the activities of superoxide dismutase (SOD) and catalase (CAT), thereby mitigating the excessive accumulation of reactive oxygen species (ROS). Furthermore, ALA increased starch content under salt stress. These findings establish a foundational understanding of the molecular mechanisms through which ALA regulates photosynthesis under salt stress in maize seedlings. Collectively, exogenous ALA enhances maize's salt tolerance by regulating photosynthesis-related pathways.

Arbuscular mycorrhizal fungi mitigate cadmium stress in maize.

Soil cadmium (Cd) pollution poses a significant environmental threat, impacting global food security and human health. Recent studies have highlighted the potential of arbuscular mycorrhizal (AM) fungi to protect crops from various heavy metal stresses, including Cd toxicity. To elucidate the tolerance mechanisms of maize in response to Cd toxicity under AM symbiosis, this study used two maize genotypes with contrasting Cd tolerance: Zhengdan958 (Cd-tolerant) and Zhongke11 (Cd-sensitive). Rhizobox experiments were conducted with and without AM inoculation, alongside Cd treatment. The results revealed that Cd stress severely impaired growth and root development in both genotypes. However, AM symbiosis significantly improved plant height, stem diameter, biomass, root morphology, photosynthetic capacity, nutrient uptake, antioxidant enzyme activity, root Cd content, and concentration, while also reducing lipid peroxidation and shoot Cd accumulation in both genotypes. Notably, AM symbiosis had a more pronounced effect on stem diameter (increased 55 %), root dry weight (118 %), root superoxide dismutase (42 %), and peroxidase activity (209 %), as well as shoot translocation factor (77 %) in Zhongke11 compared to Zhengdan958. Overall, AM symbiosis alleviated Cd toxicity in maize through multiple mechanisms, including enhanced photosynthesis, nutrient uptake, antioxidant defenses, and modulation of Cd transport and accumulation. This study provides valuable insights into the potential application of Cd-tolerant maize genotypes and AM symbiosis for managing Cd-contaminated soils.

Monitoring the spectral and agronomic behaviour of maize in response to nitrogen fertilisation

Monitoring the spectral and agronomic behaviour of maize in response to nitrogen fertilisation

ZmDREB1A controls plant immunity via regulating salicylic acid metabolism in maize.

DREB1A, a pivotal transcription factor, has long been known to regulate plant abiotic stress tolerance. However, its role in plant biotic stress tolerance and the underlying mechanisms have remained a mystery. Our research reveals that the maize ZmDREB1A gene is up-regulated in maize seedlings when the plants are infected by Rhizoctonia solani (R. solani). The maize ZmDREB1A knock-out mutant exhibits increased disease resistance against the pathogen R. solani. Further investigation showed that ZmDREB1A regulates salicylic acid (SA) metabolism by inhibiting ZmSARD1 gene and activating ZmSAGT gene expression. Additionally, the SA level was increased while the SAG level was decreased in zmdreb1a mutant seedlings when the plants were infected with the pathogen R. solani. Furthermore, overexpression of ZmSAGT in Arabidopsis reduced plant resistance to Pst DC3000 by decreasing SA levels and increasing SAG levels. These data demonstrate that ZmDREB1A regulates the metabolism of SA and controls plant immune response in maize.

Transcriptomic and metabolomic responses of maize under conventional and biodegradable microplastic stress

AbstractThe increasing accumulation of microplastics in agricultural soils potentially threatens crop safety and quality. However, studies regarding the molecular mechanisms underlying the effects of conventional and biodegradable microplastics on plant growth remain limited. Herein, we estimated the effects of biodegradable polybutylene adipate terephthalate, poly (butylene succinate), polylactic acid, and conventional non‐biodegradable polyethylene and polystyrene microplastics (at a concentration of 1% [w/w]) on the growth and physiological performance of maize (Zea mays L.). In addition, we studied the molecular mechanisms underlying the effects of these microplastics on maize. Exposure to microplastics induced the production of antioxidant enzymes and antioxidants at varying levels in the maize. While the maize antioxidant systems were induced against biodegradable microplastic exposure, maize photosynthesis was relatively more important for conventional microplastic treatments. Additionally, metabolomics and transcriptomic analyses revealed that the pathways of secondary metabolite biosynthesis, photosynthesis, energy metabolism, and carbohydrate metabolism were regulated by biodegradable and conventional microplastics. Specifically, microplastics induced the plant hormone signal transduction and mitogen‐activated protein kinase signaling pathways. Our results further indicated that microplastics could impact the plant through changing the soil environmental variables or altering the soil microbial communities. This study provides a molecular‐scale perspective on the responses of crops to microplastic contamination, and these findings will contribute to the ecological risk assessment of biodegradable and conventional microplastics.

A Comprehensive Analysis In Silico of KCS Genes in Maize Revealed Their Potential Role in Response to Abiotic Stress.

β-ketoacyl-CoA synthase (KCS) enzymes play a pivotal role in plants by catalyzing the first step of very long-chain fatty acid (VLCFA) biosynthesis. This process is crucial for plant development and stress responses. However, the understanding of KCS genes in maize remains limited. In this study, we present a comprehensive analysis of ZmKCS genes, identifying 29 KCS genes that are unevenly distributed across nine maize chromosomes through bioinformatics approaches. These ZmKCS proteins varied in length and molecular weight, suggesting functional diversity. Phylogenetic analysis categorized 182 KCS proteins from seven species into six subgroups, with maize showing a closer evolutionary relationship to other monocots. Collinearity analysis revealed 102 gene pairs between maize and three other monocots, whereas only five gene pairs were identified between maize and three dicots, underscoring the evolutionary divergence of KCS genes between monocotyledonous and dicotyledonous plants. Structural analysis revealed that 20 out of 29 ZmKCS genes are intronless. Subcellular localization prediction and experimental validation suggest that most ZmKCS proteins are likely localized at the plasma membrane, with some also present in mitochondria and chloroplasts. Analysis of the cis-acting elements within the ZmKCS promoters suggested their potential involvement in abiotic stress responses. Notably, expression analysis under abiotic stresses highlighted ZmKCS17 as a potential key gene in the stress response of maize, which presented an over 10-fold decrease in expression under salt and drought stresses within 48 h. This study provides a fundamental understanding of ZmKCS genes, paving the way for further functional characterization and their potential application in maize breeding for enhanced stress tolerance.

Responses of field-grown maize to different soil types, water regimes, and contrasting vapor pressure deficit

Abstract. Drought is a serious constraint on crop growth and production of important staple crops such as maize. Improved understanding of the responses of crops to drought can be incorporated into cropping system models to support crop breeding, varietal selection, and management decisions for minimizing negative impacts. We investigate the impacts of different soil types (stony and silty) and water regimes (irrigated and rainfed) on hydraulic linkages between soil and plant, as well as root : shoot growth characteristics. Our analysis is based on a comprehensive dataset measured along the soil–plant–atmosphere pathway at field scale in two growing seasons (2017 and 2018) with contrasting climatic conditions (low and high vapor pressure deficit). Roots were observed mostly in the topsoil (10–20 cm) of the stony soil, while more roots were found in the subsoil (60–80 cm) of the silty soil. The difference in root length was pronounced at silking and harvest between the soil types. Total root length was 2.5–6 times higher in the silty soil than in the stony soil with the same water treatment. At silking time, the ratios of root length to shoot biomass in the rainfed plot of the silty soil (F2P2) were 3 times higher than those in the irrigated silty soil (F2P3), while the ratio was similar for two water treatments in the stony soil. With the same water treatment, the ratios of root length to shoot biomass of silty soil were higher than for stony soil. The seasonally observed minimum leaf water potential (ψleaf) varied from around −1.5 MPa in the rainfed plot in 2017 to around −2.5 MPa in the same plot of the stony soil in 2018. In the rainfed plot, the minimum ψleaf in the stony soil was lower than in the silty soil from −2 to −1.5 MPa in 2017, respectively, while these were from −2.5 to −2 MPa in 2018, respectively. Leaf water potential, water potential gradients from soil to plant roots, plant hydraulic conductance (Ksoil_plant), stomatal conductance, transpiration, and photosynthesis were considerably modulated by the soil water content and the conductivity of the rhizosphere. When the stony soil and silt soil are compared, the higher “stress” due to the lower water availability in the stony soil resulted in fewer roots with a higher root tissue conductance in the soil with more stress. When comparing the rainfed with the irrigated plot in the silty soil, the higher stress in the rainfed soil resulted in more roots with a lower root tissue conductance in the treatment with more stress. This illustrates that the “response” to stress can be completely opposite depending on conditions or treatments that lead to the differences in stress that are compared. To respond to water deficit, maize had higher water uptake rate per unit root length and higher root segment conductance in the stony soil than in the silty soil, while the crop reduced transpired water via reduced aboveground plant size. Future improvements in soil–crop models in simulating gas exchange and crop growth should further emphasize the role of soil textures on stomatal function, dynamic root growth, and plant hydraulic system together with aboveground leaf area adjustments.

Methylation-sensitive random amplification polymorphism during pre-anthesis stage heat stress response in maize (Zea mays L.)

Methylation-sensitive random amplification polymorphism during pre-anthesis stage heat stress response in maize (Zea mays L.)

Exploration of Agronomic Efficacy and Drought Amelioration Ability of Municipal Solid-Waste-Derived Co-Compost on Lettuce and Maize

Organic soil amendments, such as composts, mitigate the negative impacts on the environment that are caused by poor waste management practices. However, in the sub-Saharan African region, and Malawi in particular, studies investigating the agronomical efficacy and their ability to ameliorate drought stress when used as a soil amendment are minimal. This study aimed to evaluate the efficacy of sewage sludge and municipal solid waste (MSW) co-compost to ameliorate drought stress and improve crop productivity. Three experiments were conducted (i) to determine optimal application rate for co-compost, (ii) to evaluate yield response of maize and lettuce to co-compost application under contrasting soils, and (iii) to assess the effect of co-compost under water-limited conditions. Our results indicate that an application rate of 350 g co-compost per station was the most effective. This rate is 50% and 37% lower than the currently recommended rate for applying conventional compost to green vegetables and maize, respectively. In addition, under drought conditions, the co-compost application enhanced growth in lettuce, with less wilting, increased biomass and yield, approximately 130% greater leaf yield, and a 138% improvement in root growth. Furthermore, the relative root mass ratio (RRMR) was enhanced with the co-compost application by 103% under drought stress. This suggests that the co-compost amendment resulted in a greater allocation of biomass to the roots, which is a crucial morphological attribute for adapting to drought conditions. The concentration of K in the leaves and roots of plants treated with co-compost was significantly increased by 44% and 61%, respectively, under drought conditions, which may have contributed to osmotic adjustment, resulting in a significant increase in leaf relative water content (RWC) by a magnitude of 11 times. Therefore, in light of the rising inorganic fertilizer costs and the limited availability of water resources, these results demonstrate the potential of MSW and sludge co-composting in ameliorating the drastic effects of water- and nutrient-deficient conditions and optimizing growth and yield under these constraining environments.

Single/joint effects of pyrene and heavy metals in contaminated soils on the growth and physiological response of maize (Zea mays L.).

The widespread presence of polycyclic aromatic hydrocarbons (PAHs) and toxic heavy metals in soils is having harmful effects on food crops and the environment. However, the defense mechanisms and capacity of plants to counteract these substances have not been comprehensively explored, necessitating a systematic categorization of their inhibitory effects. Accordingly, an experimental investigation was conducted to examine the growth and physiological response of maize (Zea mays L.) to different concentrations and combinations of pyrene, copper (Cu), and cadmium (Cd), with an indicator developed to assess the joint stress. The results showed that 57-day culture with contaminations significantly inhibited the plant biomass via causing root cell necrosis, inducing lipid peroxidation, and damaging photosynthesis. Cd (50-100 mg/kg) induced stronger inhibition than Cu (800-1000 mg/kg) under both single and joint stress, and their co-existence further aggravated the adverse effects and generated synergetic inhibition. Although the presence of pyrene at a low concentration (5-50 mg/kg) can somewhat diminish the metal stress, the elevated pollutant concentrations (400-750 mg/kg pyrene, 50-100 mg/kg Cd, and 800-1000 mg/kg Cu) switched the antagonistic effect to additive inhibition on maize growth. A satisfactory tolerance of a low-level pyrene and/or metal stress was determined, associated with a relative stability of chlorophyll-a (Chl-a) content and antioxidant enzymes activity. Nevertheless, the photosynthesis and antioxidant system were significantly damaged with increasing contaminant concentrations, resulting in chlorosis and biomass reduction. These findings could provide valuable knowledge for ensuring crop yield and food quality as well as implementing soil phytoremediation.

Tissue-specific chromatin accessibility and transcriptional regulation in maize cold stress response.

Maize, a vital crop globally, faces significant yield losses due to its sensitivity to cold stress, especially in temperate regions. Understanding the molecular mechanisms governing maize response to cold stress is crucial for developing strategies to enhance cold tolerance. However, the precise chromatin-level regulatory mechanisms involved remain largely unknown. In this study, we employed DNase-seq and RNA-seq techniques to investigate chromatin accessibility and gene expression changes in maize root, stem, and leaf tissues subjected to cold treatment. We discovered widespread changes in chromatin accessibility and gene expression across these tissues, with strong tissue specificity. Cold stress-induced DNase I hypersensitive sites (coiDHSs) were associated with differentially expressed genes, suggesting a direct link between chromatin accessibility and gene regulation under cold stress. Motif enrichment analysis identified ERF transcription factors (TFs) as central regulators conserved across tissues, with ERF5 emerging as pivotal in the cold response regulatory network. Additionally, TF co-localization analysis highlighted six TF pairs (ERF115-SHN3, ERF9-LEP, ERF7-SHN3, LEP-SHN3, LOB-SHN3, and AS2-LOB) conserved across tissues but showing tissue-specific binding preferences. These findings indicate intricate regulatory networks in maize cold response. Overall, our study provides insights into the chromatin-level regulatory mechanisms underpinning maize adaptive response to cold stress, offering potential targets for enhancing cold tolerance in agricultural contexts.

Single-cell transcriptomic profiling of maize cell heterogeneity and systemic immune responses against Puccinia polysora Underw.

Southern corn rust (SCR), caused by Puccinia polysora Underw (P. polysora), is a catastrophic disease affecting maize, leading to significant global yield losses. The disease manifests primarily as pustules on the upper surface of corn leaves, obscuring our understanding of its cellular heterogeneity, the maize's response to its infection and the underlying gene expression regulatory mechanisms. In this study, we dissected the heterogeneity of maize's response to P.polysora infection using single-cell RNA sequencing. We delineated cell-type-specific gene expression alterations in six leaf cell types, creating the inaugural single-cell atlas of a maize leaf under fungal assault. Crucially, by reconstructing cellular trajectories in susceptible line N110 and resistant line R99 during infection, we identified diverse regulatory programs that fortify R99's resistance across different leaf cell types. This research uncovers an immune-like state in R99 leaves, characterized by the expression of various fungi-induced genes in the absence of fungal infection, particularly in guard and epidermal cells. Our findings also highlight the role of the fungi-induced glycoside hydrolase family 18 chitinase 7 protein (ZmChit7) in conferring resistance to P. polysora. Collectively, our results shed light on the mechanisms of maize resistance to fungal pathogens through comparative single-cell transcriptomics, offering a valuable resource for pinpointing novel genes that bolster resistance to P. polysora.

Maize Fertilizer Requirement Estimates Through Nutrient Use Efficiency and Economic Analysis from Assosa, Western Ethiopia

Scientific information with regards to the response of maize (Zea mays L.) to different blended fertilizer rates for its optimum production in Nitisols of Assosa area is limited. Therefore, a field experiment was conducted on Nitisols of Assosa Agricultural Research Centre during 2016/17 cropping season to investigate the response of growth, yield and nutrient use efficiency of maize (Zea mays L.) to different blended fertilizer rates and types. The treatments consists of: control, three rates of N and P combined (92/46, 115/57 and 138/69 N/P<sub>2</sub>O<sub>5</sub> kg ha<sup>-1</sup> and two formula of blended fertilizers with different rates, formula 2 consists of 100 kg NPSB+ 73.9 N, 150 kg NPSB +110.8 N and 200 kg NPSB + 147.8 N kg ha<sup>-1</sup> and formula 4 consists of 100 kg NPSZnB + 75.1 N, 150 kg NPSZnB + 112.6 N <sup>1</sup> and 200 kg NPSZnB +150.2 N kg ha<sup>-1</sup>. The treatments were laid out as a Randomized Complete Block Design with three replications. Application of blended fertilizers (NPSB, NPSZnB) hastened days to tasseling silking and maturity by 10, 7 and 15 days, respectively as compared to combined N and P rates. Application of blended fertilizer increases significantly (p < 0.01) the plant height, cob weight, ear length, 100 kernels weight, number of kernels per row and ear height as compared to combined N and P and the control. The analysis of variance revealed that fertilizer types and rates significantly (P < 0.01) affected on grain yield, straw yield and harvest index. However there was no significant difference between the two blended fertilizer types. Maximum grain yield (7056.2 kg ha<sup>-1</sup>) was recorded with 200 Kg NPSZnB + 150.2 N kg ha<sup>-1</sup> application, while minimum grain yield 2996.0 kg ha<sup>-1</sup> was recorded from control treatment. The application of 150 kg NPSB + 110.8 N kg ha<sup>-1</sup> had highest Marginal rate of return (MRR%) and net benefit. Therefore, we recommended the treatment (150 Kg NPSB + 110.8N kg ha<sup>-1</sup>) since it produced high marginal rate of return, high net benefit and relatively small total cost of production, for maize production in Asossa area. Furthermore, based on yield, net benefit and relatively low total cost of production the farmer of Asossa area also can use 150 kg NPSZnB + 112.6 N in case of absence of NPSB in market.

Revealing molecular adaptive response in maize (Zea mays L.) under nitrogen starvation stress in low fertile sandy soil

Revealing molecular adaptive response in maize (Zea mays L.) under nitrogen starvation stress in low fertile sandy soil

A Critical Review of Recent Advances in Maize Stress Molecular Biology.

With the intensification of global climate change and environmental stress, research on abiotic and biotic stress resistance in maize is particularly important. High temperatures and drought, low temperatures, heavy metals, salinization, and diseases are widespread stress factors that can reduce maize yields and are a focus of maize-breeding research. Molecular biology provides new opportunities for the study of maize and other plants. This article reviews the physiological and biochemical responses of maize to high temperatures and drought, low temperatures, heavy metals, salinization, and diseases, as well as the molecular mechanisms associated with them. Special attention is given to key transcription factors in signal transduction pathways and their roles in regulating maize stress adaptability. In addition, the application of transcriptomics, genome-wide association studies (GWAS), and QTL technology provides new strategies for the identification of molecular markers and genes for maize-stress-resistance traits. Crop genetic improvements through gene editing technologies such as the CRISPR/Cas system provide a new avenue for the development of new stress-resistant varieties. These studies not only help to understand the molecular basis of maize stress responses but also provide important scientific evidence for improving crop tolerance through molecular biological methods.

Integration of Grain Legumes and Mbeya Manure Improves Maize Productivity on Smallholder Farms in Central Malawi

Legumes are integrated in maize-based systems to improve soil fertility and crop productivity. However, the ecosystem services from legumes vary. Crop rotation on-farm studies were conducted over two cropping seasons (2018/19 and 2019/20) in Mkanakhoti and Kaluluma Extension Planning Areas (EPAs) in Kasungu district, central Malawi. The main objective of this study was to evaluate maize response to legume cropping systems and mbeya manure. In the first season (2018/19), five treatments including sole groundnut (Gn), sole soybean (soy), sole pigeon pea (PP), and doubled-up legumes (legume + legume intercrop) - pigeon pea intercropped with groundnut (Gn+PP), and pigeon pea intercropped with soybean (Soy+PP) were grown. In the second season (2019/20), maize was planted on plots that had either sole or doubled-up legumes. These plots were split into two, one half was top dressed with 23kg N ha-1 only and the other half received 23kg N ha-1+1000kg ha-1 mbeya manure. The experiments were replicated in 2019/2020 and 2020/2021 seasons. Soil fertility was low and highly variable between farms in the study sites. Soil pH, total nitrogen (N), available phosphorus (P), organic matter (SOM) and active carbon in topsoil (0-15cm) averaged 5.1±0.5, 0.19±0.18%, 31±19.6 ppm, 1.4±0.34 %, and 193±74 mg kg-1, respectively. Application of mbeya manure to maize increased leaf chlorophyll and plant height (p<0.05). There were variations in maize yield responses to legumes with higher benefits obtained from maize rotated with doubled-up legumes than sole legumes. The results also showed that on non-responsive soils, overall, the use of mbeya manure in combination with legume systems increased the rotational maize grain yield by 88% over maize following legumes only (p<0.05), with highest yields from doubled up legumes/maize rotations followed by groundnut/maize rotations. It is therefore recommended that on highly degraded soils, farmers can increase maize productivity through integrated soil fertility management involving a combination of 23kg N/ha and 1000kg/ha of mbeya manure applied to maize rotated with doubled-up legumes (Gn+PP or Soy+PP) and sole groundnut (Gn). Key words: Doubled-up legumes, crop rotation, groundnut, pigeon pea, soybean, maize, mbeya manure

ZmHSFA2B self-regulatory loop is critical for heat tolerance in maize.

The growth and development of maize (Zea mays L.) are significantly impeded by prolonged exposure to high temperatures. Heat stress transcription factors (HSFs) play crucial roles in enabling plants to detect and respond to elevated temperatures. However, the genetic mechanisms underlying the responses of HSFs to heat stress in maize remain unclear. Thus, we aimed to investigate the role of ZmHSFA2B in regulating heat tolerance in maize. Here, we report that ZmHSFA2B has two splicing variants, ZmHSFA2B-I and ZmHSFA2B-II. ZmHSFA2B-I encodes full-length ZmHSFA2B (ZmHSFA2B-I), whereas ZmHSFA2B-II encodes a truncated ZmHSFA2B (ZmHSFA2B-II). Overexpression of ZmHSFA2B-I improved heat tolerance in maize and Arabidopsis thaliana, but it also resulted in growth retardation as a side effect. RNA-sequencing and CUT&Tag analyses identified ZmMBR1 as a putative target of ZmHSFA2B-I. Overexpression of ZmMBR1 also enhanced heat tolerance in Arabidopsis. ZmHSFA2B-II was primarily synthesized in response to heat stress and competitively interacted with ZmHSFA2B-I. This interaction consequently reduced the DNA-binding activities of ZmHSFA2B-I homodimers to the promoter of ZmMBR1. Subsequent investigations indicate that ZmHSFA2B-II limits the transactivation and tempers the function of ZmHSFA2B-I, thereby reducing the adverse effects of excessive ZmHSFA2B-I accumulation. Based on these observations, we propose that the alternative splicing of ZmHSFA2B generates a self-regulatory loop that fine-tunes heat stress response in maize.

Growth and yield responses of maize to different tillage practices and straw incorporation under different levels of gypsum in a saline-sodic soil

Soil salinity is one of the significant issues in crop production and its adverse effects have been noticed at various stages of a crop life cycle therefore to assess the remedies for mitigation of soil salinity, the present study was conducted in Khipro district, Sanghar, Sindh, Pakistan during 2018-19. The experiment was laid out in Randomized Complete Block Design (RCBD), to evaluate the growth and yield responses of maize to different tillage practices and straw incorporation under different levels of gypsum in a saline-sodic soil. The factorial study was consisted of three factors including: Tillage practices (shallow tillage [ST] and deep tillage [DT], Wheat straw incorporation (3, 7, and 10 ton. ha-1) and gypsum rates (13.5, 9 and 4.5-ton ha-1). The comparative results showed that Deep Tillage DT with wheat straw incorporation at 10-ton ha-1 (DTWS10) had significantly higher result in term of growth and yield traits followed by shallow tillage ST at 10-ton ha-1 (STWS10). Moreover, the lowest results regard growth and yield attributes were observed in Shallow tillage ST with no wheat straw incorporation (STCK) Additionally, It was also observed that gypsum application did not have significant effect (P > 0.05) on maize growth and yield, but it mitigated soil salinity and sodicity, contributing to improved crop growth and yield. Therefore, incorporating straw into saline-sodic soils can significantly (P < 0.05) enhance maize yield and its attributes, with notable effects observed after two years of treatment.