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Bainong sterility (BNS) is a thermo‐sensitive genic male sterile wheat line, characterised by anther fertility transformation in response to low temperature (LT) stress during meiosis, the failure of vacuole decomposition and the absence of starch accumulation in sterile bicellular pollen. Our study demonstrates that the late microspore (LM) stage marks the transition from the anther growth to anther maturation phase, characterised by the changes in anther structure, carbohydrate metabolism and the main transport pathway of sucrose (Suc). Fructan is a main storage polysaccharide in wheat anther, and its synthesis and remobilisation are crucial for anther development. Moreover, the process of pollen amylogenesis and the fate of the large vacuole in pollen are closely intertwined with fructan synthesis and remobilisation. LT disrupts the normal physiological metabolism of BNS anthers during meiosis, particularly affecting carbohydrate metabolism, thus determining the fate of male gametophytes and pollen abortion. Disruption of fructan synthesis and remobilisation regulation serves as a decisive event that results in anther abortion. Sterile pollen exhibits common traits of pollen starvation and impaired starch accumulation due to the inhibition of apoplastic transport starting from the LM stage, which is regulated by cell wall invertase TaIVR1 and Suc transporter TaSUT1. Summary statement: The manuscript provides new insight into the role of carbohydrate metabolism in regulating anther development and the molecular mechanisms underlying pollen abortion in a thermo‐sensitive genic male sterile winter wheat line under low temperature during meiosis. [ABSTRACT FROM AUTHOR]

Melatonin application has obvious improving effects on alleviating the drought-induced inhibition of plant growth. However, the root phenotypic dynamics in wheat treated with melatonin remain unknown. This study was conducted using RhizoPot, a novel and improvised in situ root observation device, with three treatments, including normal water condition (CK), drought condition (Ds, relative water content 45–50%), and 100 µM melatonin treatment under drought condition (MT). Results showed that MT application effectively improves root morphological indicators, including root (specific root) length, surface area, and volume; root length density; and the average root diameter of wheat plants. Also, the inhibitory effect of drought on shoot morphology, including plant height, dry weight, net photosynthesis, and stomatal aperture of leaves, were improved significantly through MT under drought condition. Life span and percent survival of fine root, lateral root, and root hair at different segments were also effectively improved under MT treatment. Compared with those shown under CK and Ds, the melatonin contents in leaves and roots were increased, and the expression levels of melatonin-synthesis-related genes (TaCOMT and TaTDC) were upregulated significantly under MT treatment. The findings of this study may clarify the drought resistance mechanism of wheat treated with melatonin under drought stress. [ABSTRACT FROM AUTHOR]

Although low light stress seriously affects florets fertility and grain number during the reproductive period, crops can be fertilized by heterologous pollen to alleviate the reduction of grain number. However, wheat is strongly autogamous, how to change to outcross after low light remains unclear. To understand the mechanisms of this change process, an approach combined morphological, physiological, and transcriptomic analyses was performed under low light stress imposed at the young microspore stage the booting stage from tetrad to uni-nucleate microspores stage. The results showed that low light stress caused pollen abortion, and the unfertilized ovary is fertilized by heterologous pollen after floret opening. Compared to control, the opening angle of lemma and glume were increased by 11.6–48.6 and 48.4–78.5%, respectively. The outcross of stressed wheat compensated for the 2.1–18.0% of grain number loss. During this process, phytohormones played an important role. Jasmonic acid (JA) and methyl jasmonate (MeJA) levels in spikelets were increased. Meanwhile, lignin and cellulose content decreased, and genes associated with cell wall related GO terms were enriched. Among the differentially expressed genes (DEGs), were identified 88-710 transcription factors genes, of which some homologs in Arabidopsis are proposed to function in lignin and cellulose, influencing the glume and lemma opening. Our finding can provide new insight into a survival mechanism to set seeds through pollination way alteration in the absence of self-fertilization after the stress of adversity. [ABSTRACT FROM AUTHOR]

Serine hydroxymethyltransferase (SHMT) plays a pivotal role in cellular one-carbon, photorespiration pathways and it influences the resistance to biotic and abiotic stresses. However, the function of SHMT proteins in wheat remains largely unexplored. In the present study, SHMT genes in five Triticeae species, Oryza sativa , and four dicotyledon species were identified based on whole genome information. The origin history of the target gene was traced by micro-collinearity analysis. Gene expression patterns of TaSHMTs in different tissues, various biotic stresses, exogenous hormones, and two biotic stresses were determined by Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The function of the selected TaSHMT3A-1 was studied by barley stripe mosaic virus-induced gene silencing in common wheat Bainong207. A total of 64 SHMT members were identified and further classified into two main classes based on the structure of SHMT proteins. The gene structure and motif composition analyses revealed that SHMTs kept relatively conserved within the same subclasses. Interestingly, there was a gene, TdSHMT7B-1 , on chromosome 7B of Triticum dicoccoides , but there was no SHMT gene on chromosome 7 of other analyzed Triticeae species; TdSHMT7B-1 had fewer exons and conserved motifs than the genes in the same subclass, suggesting that the gene of TdSHMT7B-1 has a notable evolutionary progress. The micro-collinearity relationship showed that no homologs of TaSHMT3A-1 and its two neighboring genes were found in the collinearity region of Triticum urartu , and there were 27 genes inserted into the collinearity region of T. urartu. Furthermore, qRT-PCR results showed that TaSHMT3A-1 was responsive to abiotic stresses (NaCl and cold), abscisic acid, methyl jasmonate, and hydrogen peroxide. Significantly, upon Fusarium graminearum infection, the expression of TaSHMT3A-1 was highly upregulated in resistant cultivar Sumai3. More importantly, silencing of TaSHMT3A-1 compromises Fusarium head blight resistance in common wheat Bainong207. Our new findings suggest that the TaSHMT3A-1 gene in wheat plays an important role in resistance to Fusarium head blight. This provides a valuable reference for further study on the function of this gene family. [ABSTRACT FROM AUTHOR]

Melatonin (MT) is a small molecule indole hormone that plays an important role in the regulation of biological processes and abiotic stress resistance. Previous studies have confirmed that MT promotes the normal development of plants under stress by mediating physiological regulation mechanisms. However, the physiological mechanism of exogenous MT regulating seed germination and seedling growth of wheat under salt stress is still unclear. In this study, NaCl stress decreased germination rate and inhibited seedling growth of wheat, but shoot length, root length, and plant weight of SM15 did not change significantly. The addition of 300 μM MT in the cultivation solution directly promoted the germination rate of SM15 and ZM18, and lateral root production, but decreased the germination rate of JM22 and inhibited the length of germ and radicle of three varieties under salt stress. For wheat seedling, application of MT could increase proline content, soluble protein, soluble sugar, Ca2+ content, and vital amino acid content in leaves to keep high water content, low level of H2O2 content, and low [K+]/[Na+] ratio. MT increased root vigor and [K+]/[Na+] ratio and decreased H2O2 content in root induced by salt stress. In conclusion, MT enhanced salt tolerance in wheat seeds and seedlings by regulating the synthesis of soluble protein and sugar, ion compartmentation in roots and leaves, enhancement of enzymatic systems, and changes in amino acid levels. Salt resistance varied with different varieties under the same environmental condition. SM15 was a higher salt-resistant variety and JM22 was a salt-sensitive one. In wheat production, the application of exogenous MT should consider the differences among varieties of wheat during the sowing and seedling stages. [ABSTRACT FROM AUTHOR]

Melatonin is effective in enhancing various abiotic stress resistances of plants. However, its underlying mechanisms in drought-resistance in winter wheat (Triticum aestivum L.) is not clear. The goal of this work was to investigate the effect of melatonin on seed germination and to evaluate leaf antioxidant physiology for two wheat varieties. Experiments included 20% PEG, melatonin plus 20% PEG and a control using two contrasting wheat varieties (JM22– drought sensitive and HG35– drought resistant). Melatonin levels were 0, 1, 10, 100 and 300 μmol L-1. Results revealed that 300 μmol L-1 of melatonin alleviated the negative effect of water stress on germination and increased radicle length, radicle number, and plumule length of the germinated seeds. Principal component analysis showed a significant change in amino acid content during germination and this change was dependent on melatonin concentration and the variety. Lysine (Lys) content in wheat seeds under the PEG plus 300 μmol L-1 melatonin treatment increased compared with that of the seeds under PEG alone. There was a significant and positive correlation between Lys content and morphological index of germination. During seedling growth, soluble protein was involved in osmotic adjustment and superoxide dismutase (SOD) activity was increased to mitigate the damage in the cytomembrane of JM 22 leaf under 300 μmol L-1 melatonin plus PEG treatment. The effect of melatonin was dependent on SOD activity increasing significantly for HG35—a drought resistant variety. The results of this work lays a foundation for further studies to determine if melatonin can be economically used to mitigate the impact of dry planting conditions on wheat productivity in North China Plain. [ABSTRACT FROM AUTHOR]

Regulating plant density is an important practice to improve winter wheat productivity under limited irrigation in North China Plain. Field experiments were carried out over two seasons (2014–15 and 2015–16) under three plant densities (Dh: 480–570, Dm: 360–390, Dl: 240–270 104 plants hm−2) and three irrigation levels (W0: no irrigation; W1: irrigated 80.0 mm only at the jointing stage, which also means limited irrigation; W2: irrigated 60.0 mm each at the jointing and the flowering stages). Results showed that higher numbers of spikes and higher yield were obtained at high density than that at low density under limited irrigation. Under the same irrigation, wheat culms at ripening stage and the proportion of main stem spikes increased with plant density increasing, along with the increasing of transportation amount, transportation rate, and contribution rate of pre-anthesis storage material to grain. But accumulation amount and contribution rate of post-anthesis dry matter, which was influenced by irrigation level, showed a declining trend with increasing plant density under W2 and W1. Therefore, (1) under limited water condition, yield loss could be compensated by increasing contribution rate of pre-anthesis storage material to grain with increasing plant density. (2) Meantime, under the same limited water condition, higher plant densities could promote nitrogen accumulation in grain and plant of wheat, which was significantly correlation to wheat yield. (3) Considering water and nitrogen use efficiency, medium plant density (Dm) is recommended in wet years, high plant density (Dh) may be considered to increase wheat yield in dry years. [ABSTRACT FROM AUTHOR]

This study investigated the effects of a hemicellulase dosage (20, 40, and 60 mg kg−1 of flour) on the bread quality and rheological properties of wheat aleurone-rich flour. The results showed that hemicellulase could soften dough and improve extensibility. At the optimum hemicellulase dosage (40 mg kg−1 of flour), the bread specific volume increased by 40.91% and firmness of breadcrumb decreased by 104.57% compared to those of the control. Intermolecular forces indicated that the gluten network during the proofing was mainly strengthened via disulfide bonds, hydrophobic interactions, and hydrogen bonds but not through ionic bonds after hemicellulase addition. Fourier infrared spectroscopy indicated that the hydrolytic activity of hemicellulase catalyzed the transition from α-helix to β-sheet, which verified that viscoelasticity of gluten was enhanced at a dosage of 40 mg kg−1 of flour. These results suggested that hydrolyzation of hemicellulase contributed to the structural of gluten changes, thereby improving the quality of wheat aleurone-rich bread. [ABSTRACT FROM AUTHOR]

To explore the feasibility of water-saving irrigation measures based on long-term positioning experiments on winter wheat (Triticum aestivum L.) under different irrigation and nitrogen application treatments, the main factors influencing the effect of supplementary irrigation at the anthesis stage on yield increase were explored in Gaocheng and Qingyuan, China. The experiment was designed as a split-plot arrangement, with the irrigation type as the main plot and nitrogen application rate as the sub-plots. The irrigation treatments consisted of two levels based on the amount of irrigation: 60 mm at the jointing stage (W1) and 60 mm at the jointing and anthesis stages, respectively (W2). The nitrogen treatments consisted of three levels: 0 (N0), 120 (N120), and 240 kg ha−1 (N240). Over time, the soil organic matter and total nitrogen content of N0 decreased significantly, resulting in a gradual increase in the difference between the yield increase effect of N0 and that of the nitrogen application treatment. The effect of supplementary irrigation on winter wheat yield at the anthesis stage was significantly affected by soil water storage (SWS) before sowing. The smaller the soil water storage before sowing, the larger the yield increase ratio with supplementary irrigation at the anthesis stage. The yield increase due to supplementary irrigation at the anthesis stage was also affected by precipitation during the winter wheat growth period, particularly from the jointing stage to the anthesis stage. When the precipitation from the jointing stage to the anthesis stage was < 31.9 mm, the yield increase from supplementary irrigation at the anthesis stage was significant. The results indicated that in the case of sufficient SWS before sowing, 31.9 mm of precipitation from the jointing stage to the anthesis stage could be used as a reference value for irrigation at the anthesis stage. • Excessive soil water storage reduced the yield-increasing ratio. • Insufficient soil nitrogen reduced the yield-increasing ratio. • The precipitation had a great influence on the yield increase effect. • The precipitation of 31.89 mm was an important dividing line for the yield-increasing ratio. [ABSTRACT FROM AUTHOR]

Irrigation and nitrogen application can not only increase wheat yield, but also cause nitrogen loss and soil nitrate accumulation. This study aimed to assess the effects of irrigation amount and nitrogen application rate on the soil NO 3 --N distribution and nitrogen absorption and utilization of winter wheat (Triticum aestivum L.) during the 2015–2020 growth season in the North China Plain. The experiments were designed in split plot arrangement, with irrigation amount (W0, no irrigation; W1, 60 mm irrigation at jointing; and W2, 60 mm irrigation at jointing and anthesis) as the main plots and nitrogen application rate (N0, 0; N120, 120 kg ha−1; and N240, 240 kg ha−1) as the subplots. The plants under W2N120 and W2N240 showed no significant difference in yield throughout the experimental period. With the decrease in soil total nitrogen content, the yield difference between the plants under N0 and those under N120 and N240 gradually increased throughout the experimental period. Compared with that of the plants under W2N240, the mean NO 3 --N content of the plants under W2N120 in the 0–1 m and 1–2 m soil layers decreased by 17.4% and 19.2%, respectively, in 2018–2020. The NO 3 --N concentration decreased with increasing soil depth, and the NO 3 --N concentration in each soil layer increased with increasing nitrogen application rate. Irrigation and nitrogen application increased nitrogen accumulation in vegetative organs at anthesis and nitrogen transport to grains. Compared with those of the plants under W2N240, the mean nitrogen uptake efficiency, nitrogen use efficiency, nitrogen fertilizer productivity, and nitrogen harvest index of the plants under W2N120 increased by 91.3%, 2.6%, 95.5%, and 1.9%, respectively. These results suggest that applying 120 kg ha−1 nitrogen and irrigating 60 mm at jointing and anthesis are the optimal measures for winter wheat in the North China Plain. • The effect of no nitrogen application on yield increased year by year. • Applying 240 kg ha−1 nitrogen significantly increased the accumulation of NO 3 --N in soil. • Applying 120 kg ha−1 nitrogen can achieve high yield and better nitrogen utilization. • Irrigating 60 mm at jointing and anthesis is an optimal measure. [ABSTRACT FROM AUTHOR]