Wheat Shoots Research Articles

Effect of Irrigation Scheduling and Different Sowing Dates on Water Productivity and Economics of Wheat (Triticum aestivum L.)

“Effect of moisture regime under different sowing dates of wheat crop (Triticum aestivum L.)” was investigated at Acharya Narendra Deva University of Agriculture & Technology, Ayodhya (U.P.) Agronomy Research Farm in rabi season 2021-22. Twelve main plot treatments included 15th November, 25th November, and 5th December sowing dates, while four sub plot treatments included irrigation at 0.6, 0.8, 1.0, and 1.2 IW/CPE ratios. Split plot design was used for three replications. Under 15th November sowing, all growth, yield, and characteristics rose dramatically. Irrigation at 1.0 IW/CPE ratio increased wheat shoot m-2, plant height (cm), dry matter accumulation (g m-2), yield characteristics, grain and straw yield (q ha-1) considerably. D113 (15 November planting with irrigation at 1.0 IW/CPE ratio) had the best net return and D1I2 (15 November sowing with irrigation at 0.8 IW/CPE proportion) the highest B:C ratio (2.54). Wheat yields were highest when sown on November 15. Under 15th November planting, water use efficiency was highest (9.85 kg ha-1mm-1). Irrigation with 1.0 IW/CPE ratio had the maximum water usage efficiency (9.34 kg ha-1 mm-1). The 15 November seeding with irrigation at 1.0 IW/CPE ratio yielded the highest net return (1,17,124.00), making wheat farming profitable. Maximum B:C ratio (2.54) with I1D2 therapy.

Diversity of halotolerant endophytes from wheat (Triticum aestivum) and their response to mitigate salt stress in plants

Soil salinity is one of the major limiting factors that decline crop production. About 20% of irrigated land soil is presently affected by high salinity worldwide reducing the crop yield by 20–50%. Endophytes play an important role in coping with the salinity stress in plants. In present study, 224 bacterial endophytes exhibiting discrete salt tolerance ranging from 0.5 M to 4.0 M were isolated from the shoot and root of wheat. Endophytic isolates showed varying salt tolerance potential and only a few (7.14%) possess the capability to tolerate high salt concentration (≥3.0 M NaCl). The 16S rRNA gene sequence exhibited 65 discrete OTUs recovered from the root (53.85%) and shoot tissue (46.15%) of the wheat plant. The 16S rRNA gene sequencing revealed the majority of phylum were Firmicutes (81.54%), Proteobacteria (13.85%), and Actinobacteria (4.62%) and dominated by Bacillus (63.08%), Priestia (13.85%), Pseudomonas (10.77%), Exiguobacterium and Curtobacterium (3.08% each). Moreover, this study is the first report for the abundance of certain bacterial species as endophytes from wheat cultivated under saline-affected regions like Bacillus australimaris, B. vallismortis, B. haynesii, Rossellomorea marisflavi, Exiguobacterium undae, Curtobacterium pusillum. The selected endophytes significantly reduced the detrimental influence of salt stress and enhanced various growth parameters like root length, shoot length, fresh weight, and dry weight of salt susceptible wheat variety ‘HD 2733’ as compared to the control. The present study might be beneficial to restore soil fertility and reduce the loss of crop productivity under saline stress conditions.

Determination of Heavy Metals in Root and Shoot of Durum Wheat, Plant Soil: Translocation and Bioaccumulation Factor

Heavy metals are uptake by the soil, transfer and accumulate in the various parts of durum wheat plant. The exposure of wheat crops to heavy metals poses threat to their physiological growth and human health through consumption. The study aimed at finding the concentration of heavy metals in durum wheat varieties, transfer and bioaccumulation ability, and effect of organic and conventional farming on heavy metals. The wheat samples (under organic and conventional farming) were randomly sampled at tillering, jointing, and grain filling stage. They were digested with ultra-microwave and analyzed with inductively coupled plasma. The results showed that Zn emerged as the highest concentration in the soil, root, and shoot of all wheat samples and mostly followed by Cr, Cu, Pb, and Cd. With few instances, an order of Cu>Zn>Cd>Cr>Pb>As translocation and accumulation was observed. Statistical study (α .05 and CI of 95%) revealed conventional farming increased heavy metals in the soil. Therefore, organic farming should be adopted to prevent heavy metal contamination of wheat plants and higher food chain.

GenX uptake by wheat and rice in flooded and non-flooded soils: a greenhouse experiment

GenX (hexafluoropropylene oxide dimer acid) belongs to the group of per- and poly-fluoroalkyl substance (PFAS) compounds introduced to replace perfluorooctanoic acid (PFOA), which has been phased out in industrial and consumer product formulations. While GenX has been investigated in lab animals, there is limited information available regarding its uptake and translocation in wheat and rice. This study reports on a greenhouse experiment in which wheat and rice grown under flooded and non-flooded conditions were exposed to two GenX concentrations in the soil (0.4 mg kg−1 and 2 mg kg−1). GenX was analysed in the soil, porewater and shoots using targeted liquid chromatography-tandem mass spectroscopy (LC-MS/MS) analysis. Extractable organic fluorine (EOF) was determined using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-GFMAS) instrument. Results showed that different species took up different amounts of GenX. The GenX concentration in rice shoots was found to be 2.34 (± 0.45) and 4.11 (± 0.87) μg g−1 under flooded and non-flooded conditions, respectively, at a low exposure level. At high exposure, the GenX concentrations in flooded and non-flooded rice shoots increased threefold to 10.4 (± 0.41) and 13.4 (± 0.72) μg g−1, respectively. Wheat shoots showed similar concentrations and increases between low- and high-level exposure. The translocation factor was significantly higher (P = 0.013) in non-flooded rice compared to flooded rice. The GenX bioaccumulation behaviours under the same culture conditions (e.g. temperature, humidity, light, same GenX concentration in the soil) were significantly different in non-flooded and flooded rice (P < 0.001). Non-flooded rice plants displayed a higher level of GenX bioaccumulation than flooded ones. Following exposure to GenX, flooded rice plants showed a reduction in biomass (25%) compared to the control plants (P < 0.014). Our findings indicate that GenX is a bioaccumulative compound, the presence of which likely inhibits the growth of plants.

Adaptive reactions of wheat plants to drought conditions under the influence of salicylic acid

Background. Drought is one of the most important factors affecting plant growth and productivity. The study addressed the perspectives of usage of salicylic acid, a stress protective compound, to increase the adaptive potential of Triticum aestivum L. plants under drought conditions. The effect of salicylic acid on the photosynthetic apparatus of wheat plants under the conditions of drought with a subsequent gradual resumption of watering was investigated. Materials and methods. Plants of the Podolyanka variety of wheat (Triticum aestivum L.) were the objects of our study. Seeds were pre-soaked in a solution of salicylic acid (50 mM) for 3 h. First seeds germinated in an incubator, and on the 3rd day of growth were transplanted into plastic pots (d = 14 cm). Plants were grown on soil substrate, whose humidity was maintained at 60 % of full moisture capacity – the optimal water supply. The model of drought was created by the simultaneous cessation of irrigation (30 % of soil moisture capacity) for 12 days. Upon termination of the drought, soil moisture in the pots was adjusted to 60 % of its full capacity. The control plants were grown from the seeds not treated with salicylic acid under conditions of optimal water supply (60 %). Study samples were taken from the shoots of wheat on the 7th, 9th and 12th days of the drought period and on the first day after the resumption of irrigation (14 days). The concentrations of TBA-active products, chlorophyll, carotenoids, glucose, sucrose and chlorophyllase activity were determined. Results. The influence of salicylic acid on the content of chlorophyll, carotenoids and TBA-active products along with chlorophyllase activity in shoots of wheat under the drought conditions on the early stages of ontogenesis was determined. It was found that both drought and salicylic acid modify the content of chlorophyll and carotenoids in the shoots of Triticum aestivum L., apparently by altering their metabolism. Chlorophyllase plays an important role in the adaptation of photosynthetic apparatus to the drought conditions. Our results suggest that salicylic acid causes an increase in the content of photosynthetic pigments and a decrease in chlorophyllase activity in drought conditions. In addition, salicylate causes the accumulation of glucose and sucrose in the shoot tissues of wheat plants under stressful conditions. Conclusions. Our research suggests participation of salicylic acid in the plants’ adaptation processes under the conditions of moisture deficiency. It was also found that under the effect of salicylic acid the content of TBA-active products decreases in the plant shoots under the conditions of drought. Considering the fact that the content of TBA-active products is an important indicator of lipid peroxidation intensity, the decrease of this index reveals the reduced activity of free radical processes in plant tissues under the effect of salicylic acid. Thus, it can be assumed that SA has a positive effect on plant metabolism under drought conditions.

Natural variation in a K+ -preferring HKT transporter contributes to wheat shoot K+ accumulation and salt tolerance.

Soil salinity can adversely affect crop growth and yield, and an improved understanding of the genetic factors that confer salt tolerance could inform breeding strategies to engineer salt-tolerant crops and improve productivity. Here, a group of K+ -preferring HKT transporters, TaHKT8, TaHKT9and TaHKT10, were identified and negatively regulate the wheat shoot K+ accumulation and salt tolerance. A genome-wide association study (GWAS) and candidate gene association analysis further revealed that TaHKT9-B substantially underlies the natural variation of wheat shoot K+ accumulation under saline soil conditions. Specifically, an auxin responsive element (ARE) within an 8-bp insertion in the promoter of TaHKT9-B is strongly associated with shoot K+ content among wheat accessions. This ARE can be directly bound by TaARF4 for transcriptional activation of TaHKT9-B, which subsequently attenuates shoot K+ accumulation and salt tolerance. Moreover, the tae-miR390/TaTAS3/TaARF4 pathway was identified to regulate the salt-induced root development and salt tolerance in wheat. Taken together, our study describes the genetic basis and accompanying mechanism driving phenotypic variation in wheat shoot K+ accumulation and salt tolerance. The identified tae-miR390/TaTAS3/TaARF4/TaHKT9-B module is an important regulator in wheat subjected to salt stress, which provides the potentially important genetic resources for breeders to improve wheat salt tolerance.

Exogenous strigolactones alleviate drought stress in wheat (Triticum aestivum L.) by promoting cell wall biogenesis to optimize root architecture

Exogenous strigolactones (SLs, GR24) are widely used to alleviate drought stress in wheat. The physiological and biochemical mechanisms via which SLs help overcome drought stress in wheat shoots have been reported; however, the mechanisms in wheat roots are unclear. The present study explored the effects of the exogenous application of SLs on wheat roots’ growth and molecular responses under drought stress using physiological analysis and RNA-seq. RNA-seq of roots showed that SLs mainly upregulated signal transduction genes (SIS8, CBL3, GLR2.8, LRK10L-2.4, CRK29, and CRK8) and transcription factors genes (ABR1, BHLH61, and MYB93). Besides, SLs upregulated a few downstream target genes, including antioxidant genes (PER2, GSTF1, and GSTU6), cell wall biogenesis genes (SUS4, ADF3, UGT13248, UGT85A24, UGT709G2, BGLU31, and LAC5), an aquaporin-encoding gene (TIP4-3), and dehydrin-encoding genes (DHN2, DHN3, and DHN4). As a result, SLs reduced oxidative damage, optimized root architecture, improved leaf-water relation, and alleviated drought damage. Thus, the present study provides novel insights into GR24-mediated drought stress management and a scientific basis for proposing GR24 application.

OXPHOS Organization and Activity in Mitochondria of Plants with Different Life Strategies.

The study of the supramolecular organization of the mitochondrial oxidative phosphorylation system (OXPHOS) in various eukaryotes has led to the accumulation of a considerable amount of data on the composition, stoichiometry, and architecture of its constituent superstructures. However, the link between the features of system arrangement and the biological characteristics of the studied organisms has been poorly explored. Here, we report a comparative investigation into supramolecular and functional OXPHOS organization in the mitochondria of etiolated shoots of winter wheat (Triticum aestivum L.), maize (Zea mays L.), and pea (Pisum sativum L.). Investigations based on BN-PAGE, in-gel activity assays, and densitometric analysis revealed both similarities and specific OXPHOS features apparently related to the life strategies of each species. Frost-resistant winter wheat was distinguished by highly stable basic I1III2IVa/b respirasomes and V2 dimers, highly active complex I, and labile complex IV, which were probably essential for effective OXPHOS adaptation during hypothermia. Maize, a C4 plant, had the highly stable dimers IV2 and V2, less active complex I, and active alternative NAD(P)H dehydrogenases. The latter fact could contribute to successful chloroplast-mitochondrial cooperation, which is essential for highly efficient photosynthesis in this species. The pea OXPHOS contained detergent-resistant high-molecular respirasomes I1-2III2IVn, highly active complexes IV and V, and stable succinate dehydrogenase, suggesting an active energy metabolism in organelles of this plant. The results and conclusions are in good agreement with the literature data on the respiratory activity of mitochondria from these species and are summarized in a proposed scheme of organization of OXPHOS fragments.

Metabolomics reveals the impact of nitrogen combined with the zinc supply on zinc availability in calcareous soil via root exudates of winter wheat (Triticum aestivum)

A possible mechanism for the improved availability of zinc (Zn) in soil by combining nitrogen (N) with Zn supply was investigated based on the root exudates of winter wheat. N, Zn supply as well as their combination significantly regulated nine root exudates in winter wheat; in which, the secretion of cis-aconitic acid involving in the TCA cycle, C5-branched dibasic acid metabolism, glyoxylate and dicarboxylate metabolism and 2-oxocarboxylic acid metabolism was upregulated by N, Zn supply as well as their combination. N–Zn combination induced the activities of citrate synthase and cis-aconitase in roots and shoots of winter wheat thus to increase the concentrations of citric and aconitic acid; the decrease of isocitric acid concentrations in shoots indicated the inhibited conversion of aconitic acid to isocitric acid by N–Zn combination. It revealed a possible reason for the enhanced secretion of cis-aconitic acid by N–Zn combination. Exogenous addition of 10 μ plant−1 cis-aconitate significantly increased available Zn concentrations in soil and Zn concentrations in winter wheat under N–Zn combination. Thus, the N–Zn combination regulated the metabolism of cis-aconitic acid in winter wheat, thus enhancing the secretion of cis-aconitic acid to increase the bioavailability of Zn in soil.

ВПЛИВ ОБРОБКИ НАСІННЯ МЕТАБОЛІЧНО АКТИВНИМИ РЕЧОВИНАМИ НА ФОРМУВАННЯ КСЕРОМОРФНОЇ СТРУКТУРИ ЛИСТКІВ ТА ВОДНИЙ ПОТЕНЦІАЛ ПАГОНІВ ПРОРОСТКІВ ПШЕНИЦІ М’ЯКОЇ (TRITICUM AESTIVUM L.) ЗА УМОВ ВОДНОГО ДЕФІЦИТУ

The article offers a comparative analysis of how metabolically active substances, individually and in combinations, affect the development of xeromorphic leaf structures and the water potential of shoots in common wheat (Triticum aestivum L.) seedlings when subjected to water deficit conditions simulated using PEG 6000.The study involved the use of 10 options for seed treatment : control (untreated seed + distilled water); PEG 6000 solution (12 %); solution of vitamin E (10-8M) – E; ubiquinone-10 solution (10-8M) – Q; methionine solution (0,001 %) – M; solution of paraoxybenzoic acid (POBА) (0,001 %) – P; MgSO4 solution (0,001 %) – Mg; combinations: vitamin E (10-8M) + ubiquinone-10 (10-8M) – EQ; vitamin E (10-8M) + methionine (0,001 %) + POBА (0,001 %) – EMP; vitamin E (10-8M) + methionine (0,001 %) + POBА (0,001 %) + MgSO4 (0,001 %) – EMPMg. Experimental water deficit is simulated with a 12% solution of PEG 6000.&#x0D; It was observed that treating T. aestivum wheat seeds with solutions of paraoxybenzoic acid, ubiquinone-10, and magnesium sulfate under conditions of water deficit resulted in a 17.7 %, 16.5 %, and 16.2 % increase in the assimilation surface area of seedlings, respectively, compared to those subjected to water deficit conditions simulated using PEG 6000. Furthermore, the treatment of T. aestivum wheat seeds with solutions of ubiquinone-10, methionine, and the combination of vitamin E + ubiquinone-10 stimulated chlorophyll synthesis in wheat leaves, resulting in a 14.4 %, 11.3 %, and 15.4 % increase, respectively, compared to the group of plants whose seeds were germinated under conditions of slow water supply, resulting in a smaller leaf surface area, which is indicative of a xeromorphic leaf structure.&#x0D; Treating the seeds with these specific solutions enhances photosynthetic productivity in conditions of moisture deficit by reinforcing the xeromorphic structure of the leaves. This underscores the high adaptability of wheat from the Provintsialka variety to drought conditions. &#x0D; It was determined that pre-treating seeds with a combination of vitamin E, methionine, paraoxybenzoic acid (POBA), and magnesium sulfate (MgSO4) resulted in a 1.1 % increase in water accumulation in the shoots, in comparison to the measurements obtained from seedlings whose seeds were exposed to water deficit conditions simulated using PEG 6000. &#x0D; Consequently, the application of metabolically active substances in seed treatment proves to be effective in enhancing the drought resistance of soft wheat T. aestivum. This approach can be incorporated as an integral component of the technology for cultivating grain crops under conditions of water deficit.

Porous Minerals Improve Wheat Shoot Growth and Grain Yield through Affecting Soil Properties and Microbial Community in Coastal Saline Land

Soil salinization has become a major environmental factor severely threatening global food security. The application of porous minerals could significantly ameliorate soil fertility and promote plant productivity under salt stress conditions. However, the effects of porous minerals on improving the salt resistance of grain crops in coastal saline soils is not fully studied. In this work, the shoot growth and grain yield of wheat plants grown in coastal saline fields, respectively amended with the four naturally available porous minerals, diatomite, montmorillonite, bentonite and zeolite, were assessed. The application of porous minerals, especially zeolite, significantly improved the biomass and grain yield of wheat plants under saline conditions, as demonstrated by the augmented plant fresh mass (14.8~61.2%) and increased seed size (3.8~58.8%) and number (1.4~57.5%). Soil property analyses exhibited that porous-mineral amendment decreased soil sodium content and sodium absorption ratio, and increased soil nutrients in both the rhizosphere and nonrhizosphere of wheat plants. Further quantitative-PCR and 16S high-throughput sequencing analysis revealed that porous-mineral application also remarkably increased the abundance of bacterial 16S rRNA (0.8~102.4%) and fungal 18S rRNA (89.2~209.6%), and altered the composition of the soil microbial community in the rhizosphere of wheat. Our findings suggest that zeolite could be used as an ideal salt soil amendment, and the changes in soil properties and microorganisms caused by the application of porous minerals like zeolite improved the salt resistance of wheat plants in coastal saline land, leading to increased shoot growth and seed production.

Comparative transcriptomic profiling reveals differentially expressed genes and important related metabolic pathways in shoots and roots of a Saudi wheat cultivar (Najran) under salinity stress.

High salinity of soil is a threatening constraint for agricultural output worldwide. The adverse effects of salt stress on plants can be revealed in different manners, from phenotypic to genetic changes. A comparative RNA-Sequencing analysis was done in roots and shoots of bread wheat, Najran cultivar between plants grown under unstressed control condition (0 mM NaCl) and salt treatment (200 mM NaCl). More than 135 million and 137 million pair-end reads were obtained from root and shoot samples, respectively. Of which, the mapped reads to Triticum aestivum genome IWGSC_V51 ranged from 83.9% to 85% in the root and 71.6% to 79% in the shoot. Interestingly, a comparison of transcriptomic profiling identified that total number of significantly differentially expressed genes (DEGs) examined in the roots was much higher than that found in the shoots under NaCl treatment, 5829 genes were differentially expressed in the roots whereas 3495 genes in the shoots. The salt-induced change in the transcriptome was confirmed by RT-qPCR using a set of randomly selected genes. KEGG enrichment analysis classified all DEGs in both roots and shoots into 25 enriched KEGG pathways from three main KEGG classes: Metabolism, organismal systems and genetic information processing. According to that, the most significantly regulated pathways in the root and shoot tissues were glutathione metabolism and biosynthesis of secondary metabolites such as phenylpropanoids and galactose metabolism suggesting that these pathways might participate in wheat salt tolerance. The findings highlight the importance of the control of oxidative stress via Glutathione and phenylpropanoids and the regulation of galactose metabolism in the roots and shoots for salt-tolerance in wheat. They open promising prospects for engineering salt-tolerance in this important crop via targeted improvement of the regulation of key genes in the production of these compounds.

Improving wheat seedling quality through deep ploughing and soil compaction at sowing in lime concretion black soil.

The straw incorporation in lime concretion black soil compromises the emergence and quality of winter wheat seedlings in Huaibei Plain, China, lowering the potential of wheat productivity. To overcome the disadvantage, a two-year field experiment was conducted in 2017-18 and 2018-19 to investigate the effects of different tillage modes on seedling emergence and subsequent seedling growth, and final grain yield (GY) in winter wheat. The modes are rotary tillage with compaction after sowing (RCT), rotary tillage after deep ploughing (PT) and rotary tillage after deep ploughing with compaction after sowing (PCT), with the traditional rotary tillage (RT) method as the control. Compared to RT, greater soil moisture content (SMC) at the seedling stage was observed in deep ploughing or compaction treatment, and the highest SMC was achieved in PCT; the time of reaching the maximum number of seedlings was 1 d sooner in RCT or PT, and 3 d in PCT; the seedling number in RCT, PT and PCT was significantly increased by 32.6%, 34.5% and 61.5% respectively. The population size, shoot and root growth of winter wheat in ploughing mode was significantly enhanced than that of rotary treatment at the over-wintering stage; compared to no compaction after sowing, plant growth in compaction treatments was significantly promoted with greater plant population size and height of seedlings. At harvest, GY in RCT, PT and PCT was significantly improved by 5.87%, 10.8% and 16.4%, respectively, compared to RT and the highest GY was achieved in PCT by up to 8, 350.1 kg ha-1 due to the increased spike number. In conclusion, the seedling quality in the straw incorporation practice was improved through rotary after deep ploughing and compaction after sowing for lime concretion black soil in Huaibei Plain, China or a similar soil type.

Interactions between arbuscular mycorrhizal fungus and indigenous compost improve salt stress tolerance in wheat (Triticum durum)

Salinity is one of the most harmful abiotic stresses that affect wheat development and metabolism. The main objective of this study was to evaluate the potential effects of biostimulants/biofertilizers as an environment-friendly practice for improving wheat tolerance to salinity. A greenhouse experiment was conducted on a durum wheat variety: Carioca. The wheat seedlings were treated with a pure strain of arbuscular mycorrhizal fungus (M; Rhizoglomus irregulare) and /or compost (C; made from olive pomace with olive mill wastewater under non-saline, medium and high saline (100 and 200 mM NaCl) conditions. The results showed that C application significantly decreased mycorrhizal infection. Salinity reduced growth, physiological functioning, and biochemical processes. However, selected biostimulants/biofertilizers application, especially C alone, mitigated the negative effects of salinity by improving wheat shoot dry weight (65%), root dry weight (22%), phosphorus uptake (544%), and stomatal conductance (180%) than control under 200 mM NaCl. In addition, C application alone and/or M treatments improved osmotic adjustment and antioxidant system, maintained a higher stem water potential, reduced malondialdehyde and hydrogen peroxide content and increased glomalin secretion in soil. These results showed that compost and/ or Rhizoglomus irregulare could mediate salt tolerance and enhance wheat production in degraded areas.

Co-inoculation effect of Azospirillum brasilense and Bacillus megaterium with phosphorus on wheat (Triticum aestivum L.) growth in calcareous soil

Using microbial bio fertilizer has been widely used in recent years because it improves the plant growth and nutrients uptake A plastic pot experiment was carried out under plastic house at the College of Agricultural Engineering Sciences, University of Sulaimani, Bakrajo, from November 2021 to May 2022 to study the effect of co-inoculation of bacteria A. brasilense and B. megaterium bio fertilizer and their interaction on growth responses of wheat (Triticum aestivumn L.) at various P levels (0, 40, 80,120, and 160 kg P ha-1). The experiment was performed in a factorial experiment with completed randomized design (CRD) in a silty clay soil with three replications. Before harvesting chlorophyll, intensity was measured, and after that plants were harvested. Results showed that co-inoculation was significantly effect on increasing chlorophyll intensity and plant dry biomass on wheat plant and nutrient uptake. The maximum value was 36.54 spad and 19.82 g pot-1 recorded at (160 kg P ha-1) respectively, while the maximum value of wheat shoot N, and Zn nutrients contend was 27.97 g kg-1 and 45.44 µg g-1 respectively recorded at (160 kg P ha-1), while the maximum value for P, K and Fe was 5.33 g kg-1, 26.43 g kg-1 and 301.74 µg g-1 recorded at (120 kg P ha-1 ). But when the soil inoculated with A. brasilense significantly increased chlorophyll intensity and plant dry biomass compared with control. The maximum value was 28.50 spad and 19.22 g pot-1 recorded at (160 kg P ha-1), while the highest value for wheat shoot N, P, K Fe and Zn nutrients contend were 21.10 g kg-1, 2.80 g kg-1, 15.77 g kg-1, 201.56 µg g-1 and 26.45 µg g-1 respectively recorded at (160 kg P ha-1), and when the soil inoculated with B. megaterium increased chlorophyll intensity and plant dry biomass compared with control. The highest value was 18.50 spad and 16.31 g pot-1 recorded at (160 kg P ha-1). while the maximum value for wheat shoot N, P, K and Fe nutrients were 20.26 g kg-1, 4.43 g kg-1, 17.83 g kg-1 and 276.74 µg g-1 respectively recorded at (160 kg P ha-1), while the maximum value for Zn was 32.85 µg g-1 recorded at (120 kg P ha-1).

On the Possible Trade-Off between Shoot and Root Biomass in Wheat.

Numerous studies have shown that under a limited water supply, a larger root biomass is associated with an increased above-ground biomass. Root biomass, while genetically controlled, is also greatly affected by the environment with varying plasticity levels. In this context, understanding the relationship between the biomass of shoots and roots appears prudent. In this study, we analyze this relationship in a large dataset collected from multiple experiments conducted up to different growth stages in bread wheat (Triticum aestivum L.) and its wild relatives. Four bread wheat mapping populations as well as wild and domesticated members of the Triticeae tribe were evaluated for the root and shoot biomass allocation patterns. In the analyzed dataset the root and shoot biomasses were directly related to each other, and to the heading date, and the correlation values increased in proportion to the length of an experiment. On average, 84.1% of the observed variation was explained by a positive correlation between shoot and root biomass. Scatter plots generated from 6353 data points from numerous experiments with different wheats suggest that at some point, further increases in root biomass negatively impact the shoot biomass. Based on these results, a preliminary study with different water availability scenarios and growth conditions was designed with two cultivars, Pavon 76 and Yecora Rojo. The duration of drought and water level significantly affected the root/shoot biomass allocation patterns. However, the responses of the two cultivars were quite different, suggesting that the point of diminishing returns in increasing root biomass may be different for different wheats, reinforcing the need to breed wheats for specific environmental challenges.

Interactive effect of silicon application and Azospirillum brasilense inoculation on wheat nutrient uptake and accumulation combined with N application rates

This study was developed to investigate the interactive effect of silicon (Si) application and the inoculation of plant growth promoting bacteria (PGPB) Azospirillum brasilense on wheat nutrient uptake and accumulation on biomass and grains when combined with nitrogen (N) application rates. The study was set up in a Rhodic Hapludox under no-till system, located in Selvíria, state of Mato Grosso do Sul, Brazil (tropical Savannah region). Treatments were tested in a randomized complete block design with four replicates, arranged in a full factorial design 2 × 2 × 5 and included: i) two soil amendment sources (Ca and Mg silicate as Si source and dolomitic limestone); ii) two seed inoculation (with and without A. brasilense) and iii) five N application rates applied as side-dress (0, 50, 100, 150 and 200 kg ha−1). Increasing N application rates positively influenced wheat nutrition with increased nutrient and Si uptake in shoot. Calcium and Mg silicate positively influenced wheat nutrition with greater shoot Si and grain N, P, K, B, Cu, Fe, Mn, Zn and Si uptake. In addition, Si was the third and sixth element most absorbed in wheat shoot and grain respectively. Inoculation with A. brasilense was found to increase nutrient uptake with greater shoot K and S and grain N, P, K, Mg, S, B, Cu, Mn, Zn and Si uptake. Azospirillum brasilense inoculation provided greater N uptake, with an increase of 5.8 and 8.9% on shoot and grain uptake.

Comparative metabolomic profiling reveals molecular mechanisms underlying growth promotion and disease resistance in wheat conferred by Piriformospora indica in the field

ABSTRACT Piriformospora indica, a plant root-colonizing basidiomycete fungus, exhibits strong growth-promoting activity in symbiosis with a broad range of plants. Here, we report the potential of P. indica to improve growth, yield, and disease resistance in wheat in the field. In the present study, P. indica successfully colonized wheat through chlamydospores and formed dense mycelial networks that covered roots. Plants subjected to the seed soaking (SS) treatment with P. indica chlamydospore suspensions enhanced tillering 2.28-fold compared to the non-inoculated wheat in the tillering stage. In addition, P. indica colonization promoted vegetative growth significantly during the three-leaf, tillering, and jointing stages. Moreover, the P. indica-SS-treatment enhanced wheat yield by 16.37 ± 1.63%, by increasing grains per ear and panicle weight and decreased damage to wheat shoot and root architecture markedly, with high field control effects against Fusarium pseudograminearum (81.59 ± 1.32%), Bipolaris sorokiniana (82.19 ± 1.59%), and Rhizoctonia cerealis (75.98 ± 1.36%). Most of the primary metabolites, such as amino acids, nucleotides, and lipids, involved in vegetative reproduction were increased in P. indica-SS-treatment plants, whereas secondary metabolites, such as terpenoids, polyketides, and alkaloids, decreased following P. indica inoculation. The up-regulated processes of protein, carbohydrate, and lipid metabolism indicated that P. indica colonization increased growth, yield, and disease resistance via the acceleration of plant primary metabolism. In conclusion, P. indica improved morphological, physiological, and metabolic substance levels, and further promoted its growth, yield, and disease resistance in wheat.

Polar Metabolites Profiling of Wheat Shoots (Triticum aestivum L.) under Repeated Short-Term Soil Drought and Rewatering.

The response of wheat (Triticum aestivum L.) plants to the soil drought at the metabolome level is still not fully explained. In addition, research focuses mainly on single periods of drought, and there is still a lack of data on the response of plants to short-term cyclical periods of drought. The key to this research was to find out whether wheat shoots are able to resume metabolism after the stress subsides and if the reaction to subsequent stress is the same. Gas chromatography coupled with mass spectrometry (GC-MS) is one of the most valuable and fast methods to discover changes in the primary metabolism of plants. The targeted GC-MS analyses of whole shoots of wheat plants exposed (at the juvenile stage of development) to short-term (five days) mild soil drought/rewatering cycles (until the start of shoot wilting) enabled us to identify 32 polar metabolites. The obtained results revealed an accumulation of sugars (sucrose, fructose, glucose, and 1-kestose), proline, and malic acid. During five days of recovery, shoots regained full turgor and continued to grow, and the levels of accumulated metabolites decreased. Similar changes in metabolic profiles were found during the second drought/rewatering cycle. However, the concentrations of glucose, proline, and malic acid were higher after the second drought than after the first one. Additionally, the concentration of total polar metabolites after each plant rewatering was elevated compared to control samples. Although our results confirm the participation of proline in wheat responses to drought, they also highlight the responsiveness of soluble carbohydrate metabolism to stress/recovery.

Integrated use of plant growth-promoting bacteria and nano-zinc foliar spray is a sustainable approach for wheat biofortification, yield, and zinc use efficiency.

The intensive cropping system and imbalance use of chemical fertilizers to pursue high grain production and feed the fast-growing global population has disturbed agricultural sustainability and nutritional security. Understanding micronutrient fertilizer management especially zinc (Zn) through foliar application is a crucial agronomic approach that could improve agronomic biofortification of staple grain crops. The use of plant growth-promoting bacteria (PGPBs) is considered as one of the sustainable and safe strategies that could improve nutrient acquisition and uptake in edible tissues of wheat to combat Zn malnutrition and hidden hunger in humans. Therefore, the objective of this study was to evaluate the best-performing PGPB inoculants in combination with nano-Zn foliar application on the growth, grain yield, and concentration of Zn in shoots and grains, Zn use efficiencies, and estimated Zn intake under wheat cultivation in the tropical savannah of Brazil. The treatments consisted of four PGPB inoculations (without inoculation, Azospirillum brasilense, Bacillus subtilis, and Pseudomonas fluorescens, applied by seeds) and five Zn doses (0, 0.75, 1.5, 3, and 6 kg ha-1, applied from nano ZnO in two splits by leaf). Inoculation of B. subtilis and P. fluorescens in combination with 1.5 kg ha-1 foliar nano-Zn fertilization increased the concentration of Zn, nitrogen, and phosphorus in the shoot and grain of wheat in the 2019 and 2020 cropping seasons. Shoot dry matter was increased by 5.3% and 5.4% with the inoculation of P. fluorescens, which was statistically not different from the treatments with inoculation of B. subtilis as compared to control. The grain yield of wheat was increased with increasing nano-Zn foliar application up to 5 kg Zn ha-1 with the inoculation of A. brasilense in 2019, and foliar nano-Zn up to a dose of 1.5 kg ha-1 along with the inoculation of P. fluorescens in the 2020 cropping season. The zinc partitioning index was increased with increasing nano Zn application up to 3 kg ha-1 along with the inoculation of P. fluorescens. Zinc use efficiency and applied Zn recovery were improved at low doses of nano-Zn application in combination with the inoculation of A. brasilense, B. subtilis, and P. fluorescens, respectively, as compared to control. Therefore, inoculation with B. subtilis and P. fluorescens along with foliar nano-Zn application is considered a sustainable and environmentally safe strategy to increase nutrition, growth, productivity, and Zn biofortification of wheat in tropical savannah.