Optimization of the morphological, structural, and physicochemical properties of maize starch using straw returning and nitrogen fertilization in Northeast China.

The combination of straw returning and nitrogen (N) fertilization is a popular tillage mode and essential strategy for achieving stable yield and high quality. However, the optimal combination strategy and the influence of tillage mode on the morphological, crystalline, and molecular structures of maize starch remain unclear. We conducted a long-term field experiment over 7 years in Northeast China using two tillage modes, rotary tillage with straw returning (RTS) and plow tillage with straw returning (PTS), and four N application rates. The relative crystallinity, 1045/1022 cm-1 value, and B2 and B3 chains of maize starch were higher under RTS than under PTS, resulting in increased stability of starch and improvements in gelatinization enthalpy and temperature. The surface of the starch granules induced by N fertilizer was smoother than that under the N0 (0 kg N ha-1) treatment. The proportion of amylose content, solubility, swelling power, and light transmittance increased under N2 (262 kg N ha-1) treatment, along with improvement in starch pasting properties. These results suggest that RTS combined with N2 treatment can regulate the morphological, structural, and physicochemical characteristics of maize starch, providing an essential reference for improving the quality of maize starch from an agronomic point of view.

Linkages of microbial community structure and root exudates: Evidence from microbial nitrogen limitation in soils of crop families.

Rhizosphere microorganisms are critical for crop nutrient cycling and soil ecological functions in agroecosystem soils; however, there is limited information regarding the role of root exudates in determining soil microbial communities and functions in plant-soil systems, especially for microbial nutrient limitations. In the present study, rhizosphere soil samples were collected from the main food crop families, including maize, soybean, potato, and buckwheat, representing the cereals, Leguminosae, Solanaceae, and Polygonaceae families, in the northern Loess Plateau, China, to investigate soil microbial co-occurrences and assembly processes and the relationship between soil microbes and root exudates. The results showed that the crop families greatly regulated the soil microbial community composition and assembly, and all microorganisms of the four species were subjected to N limitation via the vector analysis. The topological properties of the soil microbial networks varied with the crop family, demonstrating that the ecological relationships of bacterial taxa are more complex than those of fungi. Stochastic processes were more important in stimulating assembly across the four crop families; the non-dominated process governed >60 % of the critical ecological turnover in community assembly, whereas dispersal limitation was the key factor influencing fungal community assembly. Furthermore, the metabolic profiles of root exudates in response to microbial N limitation varied by family. Microbial function and metabolic limitations were strongly associated with variations in root exudates, especially amino acids and organic acids, which were directly facilitated by crop families. Our results highlight the key roles of root exudates in stimulating microbial community structure and ecological functions from the perspective of microbial nutrient limitation and improve our understanding of plant-microbe interactions in agricultural ecosystems.

Phosphorous fertilization alleviates shading stress by regulating leaf photosynthesis and the antioxidant system in mung bean (Vigna radiata L.).

Shading can limit photosynthesis and plant growth. Understanding how phosphorus (P) application mitigates the effects of shading stress on morphology and physiology of mung beans (Vigna radiata L.) is of great significance for the establishment of efficient planting structures and optimizing P-use management. The effects of various light environments (non-shading stress, S0; low light stress, S1; severe shading stress, S2) on the growth of two mung bean cultivars (Xilv1 and Yulv1) and the role of P application (0 kg ha-1, P0; 90 kg ha-1, P1; 150 kg ha-1, P2) in such responses were investigated in a field experiment. Our results demonstrated that shading decreased the dry matter accumulation of mung bean markedly by limiting photosynthesis capacity and disrupting agronomic traits. For the leaf areas of the two cultivars, chlorophyll a+b, the net photosynthetic and electron transport rates were increased by 16.8%, 20.0%, 15.5%, and 12.5% under P1 treatment, and by 32.4%, 40.3%, 16.3% and 12.8% under P2 treatment, respectively, when compared to those for the non-fertilized plants under shading stress. These responses resulted in increased light capture and weak light utilization. Moreover, the activities of superoxide dismutase and peroxidase were enhanced by 20.9% and 43.7%, respectively; malondialdehyde and superoxide anion contents were reduced by 18.6% and 14.1%, respectively, under P application. These findings suggest that P application moderately mitigates the damage caused by shading stress and enhances tolerance by regulating mung bean growth. In addition, Xilv1 was more sensitive to P under shading stress than Yulv1.

Identification and antioxidant capacity of 4-hydroxyphenylpyruvate dioxygenase (HPPD), a new favored herbicide target, in Apis cerana cerana.

4-Hydroxyphenylpyruvate dioxygenase (HPPD), a nonheme oxygenase, catalyzes the second step of the tyrosine catabolic pathway, which is shared by almost all aerobic life forms. This demonstrates its importance in aerobic biology. We isolated an HPPD homolog from Apis cerana cerana and named it AccHPPD. AccHPPD has an open reading frame (ORF) length of 900 bp and encodes a 299 amino acid protein that has a predicted molecular weight of 34.67 kDa and an isoelectric point of 6.27. Amino acid analysis showed that AccHPPD contained three conserved metal ion active sites, H-101, H-184 and E-267. Real-time fluorescence quantitative PCR (RT-qPCR) analysis showed that AccHPPD mainly existed in specific tissue sites, mainly high in the legs and in the thorax and epidermis, and in specific developmental stages, mainly adults. Under temperature, pesticide, heavy metal and ultraviolet (UV) radiation treatments, the expression level was downregulated, but under H2O2 treatment, the expression level was upregulated. Exogenous expression of the recombinant AccHPPD plasmid in E. coli enhanced the resistance to HgCl2 and H2O2. Inhibition of AccHPPD activity was demonstrated by the upregulation of the tyrosine content after feeding with the inhibitor 2-(2-nitro-4-trifluoromethyl benzoyl)-1,3-cyclohexanedione (NTBC). After silencing of AccHPPD, the activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) decreased, and the expression levels of AccBax- and AccCaspase8-related genes were upregulated. The antioxidant genes AccCAT, AccGSTZ1, AccGSTD, AccSOD2, AccTpx3, AccCYP4G11, AccGDTS4, AccGSTO2 and AccMSRA were all upregulated. These results suggest that AccHPPD may serve an integral function in the response of A. cerana cerana to oxidative stress.

Cultivar sensitivity of broomcorn millet (Panicum miliaceum L.) to nitrogen availability is associated with differences in photosynthetic physiology and nitrogen uptake.

In order to explore the influences of low nitrogen (N) fertilizer on the growth performances of two broomcorn millet (Panicum miliaceum L.) cultivars with different N tolerances, the field experiment was carried out with a low-N-tolerant cultivar (BM 184) and a low-N-sensitive cultivar (BM 230) under three N levels (0, 75 and 150 kg N ha-1) in the Loess Plateau, China. 150 kg N ha-1 was conventional N application rate and considered as the control. Compared to typical N supply, low N fertilizer significantly weakened the photosynthetic capacity by increasing the light transmission ratio and decreasing leaf area index, resulting in reduced biomass accumulation. BM 184 held the longer duration of the biomass increase phase and larger relative growth rate than BM 230 as well as higher photosynthetic parameters (i.e., relative chlorophyll content, net photosynthetic rate, and transpiration rate) did under low N treatments. Such optimized physiological characteristics contributed to more effective N uptake and transportation from the stems, leaves, and sheaths to grains in the BM 184. Furthermore, compared with BM 230, BM 184 had higher rhizosphere soil fertility and soil enzyme activity under low N conditions; consequently, combined with the physiological characteristics for aboveground and soil nutrient status for belowground, higher productivity was obtained in BM 184 than that in BM 230 over the two years study. Overall, our results demonstrated that low-N-tolerant cultivar achieved reduced N fertilizer input with increased efficiency by optimizing growth performances in semi-arid cultivation areas.

Mung Bean (Vigna radiata L.) Source Leaf Adaptation to Shading Stress Affects Not Only Photosynthetic Physiology Metabolism but Also Control of Key Gene Expression.

Shading stress strongly limits the effective growth of plants. Understanding how plant morphogenesis and physiological adaptation are generated in response to the reduced low light conditions is important for food crop development. In this study, two mung bean (Vigna radiata L.) cultivars, namely, Xilv 1 and Yulv 1, were grown in the field to explore the effects of shading stress on their growth. The results of morphology, physiology, and biochemistry analyses showed that the shading stress significantly weakened the leaf photosynthetic capacity as measured by the decreased net photosynthetic rate, stomatal conductance, and transpiration rate and increased intercellular CO2 concentration. These responses resulted in plant morphological characteristics that increased the light energy absorption in low light conditions. Such variations occurred due to the leaf anatomical structure with destroyed palisade tissues and spongy tissues. Under shading stress, Yulv 1 showed higher physiological metabolic intensity than Xilv 1, which was related to changes in chlorophyll (Chl), such as Chl a and b, and Chl a/b ratio. Compared with normal light conditions, the Chl fluorescence values, photosynthetic assimilation substances, and enzyme activities in mung bean plants under shading stress were reduced to different extent. In addition, the relative expression levels of VrGA2ox, VrGA20ox1, VrGA3ox1, VrROT3, and VrBZR1, which are related to endogenous hormone in mung bean leaves, were upregulated by shading stress, further leading to the improvements in the concentrations of auxin, gibberellins (GAs), and brassinolide (BR). Combined with the morphological, physiological, and molecular responses, Yulv 1 has stronger tolerance and ecological adaptability to shading stress than Xilv 1. Therefore, our study provides insights into the agronomic traits and gene expressions of mung bean cultivars to enhance their adaptability to the shading stress.

Exogenous brassinosteroids increases tolerance to shading by altering stress responses in mung bean (Vigna radiata L.).

Plant steroidal hormones, brassinosteroids, play a key role in various developmental processes of plants and the adaptation to various environmental stresses. The purpose of this research was to evaluate the effect of exogenous 24-epibrassinolide (EBR) application on the morphology, photosynthetic characteristics, chlorophyll fluorescence parameters, photosynthetic enzymes activities, and endogenous hormone content of mung bean (Vigna radiata L.) leaves under shading stress environment. Two mung bean cultivars, Xilv 1 and Yulv 1, were tested. The results showed that all of the investigated data were significantly affected by shading stress; however, foliar application of EBR increased the net photosynthetic rate, transpiration rate, stomatal conductance, and decreased intercellular CO2 concentration of mung bean leaves under shading condition. Increased photosynthetic capacity in EBR-treated leaves was accompanied by improvement in higher photosynthetic enzymes activities. EBR-treated leaves exhibited more quantum yield of PSII electron transport and efficiency of energy capture than the control, which was mainly due to clearer leaf anatomical structure such as palisade tissues and spongy tissues, further resulting in altered plant morphological characteristics. Moreover, the treatment with EBL regulated the endogenous hormone content, including the decreased gibberellins and increased brassinolide, although to different levels. Combined with the morphological and physiological responses, we concluded that exogenous EBR treatment is beneficial to enhancing plant tolerance to shading stress and mitigating injure from weak light. The modifications of the physiological metabolism through EBR application may be a potential strategy to weaken shading stress in the future sustainable agricultural production.

Liquor Flavour Is Associated With the Physicochemical Property and Microbial Diversity of Fermented Grains in Waxy and Non-waxy Sorghum (Sorghum bicolor) During Fermentation.

The fermentation process of Chinese Xifeng liquor involves numerous microbes. However, the sources of microbes in fermented grain and the link between liquor flavour and physicochemical properties and microbial diversity during fermentation still remain unknown. Herein, two waxy (JiNiang 2 [JN-2] and JinNuo 3 [JN-3]) and four non-waxy (JiZa 127 [JZ-127], JinZa 34 [JZ-34], LiaoZa 19 [LZ-19], and JiaXian [JX]) sorghum varieties were selected for the comprehensive analysis of the relationship between liquor flavour and the physicochemical properties and microbial diversity of fermented grains. Results showed that ethyl acetate was the main flavour component of JZ-127, JZ-34, and JX, whereas ethyl lactate was mainly detected in JN-2, JN-3, and LZ-19. Ethyl lactate accounted for half of the ethyl acetate content, and JX exhibited a higher liquor yield than the other sorghum varieties. The fermented grains of waxy sorghum presented higher temperature and reducing sugar contents but lower moisture and starch contents than their non-waxy counterparts during fermentation. We selected JN-3 and JX sorghum varieties to further investigate the microbial changes in the fermented grains. The bacterial diversity gradually reduced, whereas the fungal diversity showed nearly no change in either JN-3 or JX. Lactobacillus was the most abundant bacterial genus, and its level rapidly increased during fermentation. The abundance of Lactobacillus accounted for the total proportion of bacteria in JX, and it was higher than that in JN-3. Saccharomyces was the most abundant fungal genus in JX, but its abundance accounted for a small proportion of fungi in JN-3. Four esters and five alcohols were significantly positively related to Proteobacteria, Bacteroidetes, and Actinobacteria; Alphaproteobacteria, Actinobacteria, and Bacteroidia; Bacillales, Bacteroidales, and Rhodospirillales; and Acetobacter, Pediococcus, and Prevotella_7. This positive relation is in contrast with that observed for Firmicutes, Bacilli, Lactobacillales, and Lactobacillus. Meanwhile, Aspergillus was the only fungal microorganism that showed a significantly negative relation with such compounds (except for butanol and isopentanol). These findings will help in understanding the fermentation mechanism and flavour formation of fermented Xifeng liquor.

Transcriptome analysis reveals the mechanism associated with dynamic changes in fatty acid and phytosterol content in foxtail millet (Setaria italica) during seed development.

Foxtail millet (Setaria italica) is an excellent source of beneficial natural fatty acids and phytosterols. However, the mechanisms underlying the dynamic changes of fatty acids and phytosterols during seed development are unknown. In this study, a comprehensive dynamic change analysis of the bioactive compounds during seed development was conducted in two cultivars with different crude fat content (high-fat, JG 35 [5.40%]; and low-fat, JG 39 [2.90%]). GC-FID/MS analysis showed that the proportion of unsaturated fatty acids (UFAs) were higher than the saturated fatty acids (SFAs). UFA content first increased, then decreased during seed development, while SFA content showed the opposite trend. Oil contents continuously increased with seed development, especially at the S2 stage. Phytosterol contents initially increased, then decreased with seed development. Transcriptome analysis revealed that 152 genes were associated with fatty acid metabolism and phytosterol biosynthesis, of which 46 and 62 were related to UFA and phytosterol biosynthesis, respectively. Furthermore, the key genes involved in fatty acid synthesis (ACCase and FATA/B), triacylglycerol biosynthesis (LACS, GPAT, and DGAT), and phytosterols synthesis (CAS1, STM1, EGR6, and DWF1) were overexpressed. This led to maximum UFA, oil, and phytosterol accumulation in JG 35 at the S2 stage. This study reveals the mechanism behind the dynamic changes of fatty acid and phytosterol contents in foxtail millet during seed development.

Identifying the primary meteorological factors affecting the growth and development of Tartary buckwheat and a comprehensive landrace evaluation using a multi-environment phenotypic investigation.

BACKGROUND: Tartary buckwheat (Fagopyrum tataricum) is a traditional edible and medicinal crop and has been praised as one of the green foods for humans in the 21st century. However, its production and promotion are restricted by the low yields of current varieties. The interaction of genotype and environment could lead to inconsistent phenotypic performance of genotypes across different environments. Climate change has intensified these effects and poses a substantial threat to crop production. RESULTS: In the present study, the effects of meteorological factors on the phenotypic traits of 200 Tartary buckwheat landraces across four macro-environments were investigated. Overall, the phenotypic performance of these Tartary buckwheat landraces was markedly varied across the different environments. Also, the average daily temperature and precipitation had relatively higher impacts on phenotypic performance. The results also revealed the negative impacts of relative humidity on the yield-related traits. Twenty-five Tartary buckwheat landraces were ultimately identified as having good overall phenotypic performance and high yield stability. CONCLUSION: Understanding the impacts of meteorological factors on the phenotypic performance of crops can guide appropriate measures and facilitate germplasm selection for yield enhancement in the context of climate change. The landraces selected comprehensively in this study could be used as parents or intermediate materials for breeding high-quality Tartary buckwheat varieties in the future. The methods used could also be extended to other crops for breeding and germplasm innovation. © 2021 Society of Chemical Industry.

Intercropping Alters the Soil Microbial Diversity and Community to Facilitate Nitrogen Assimilation: A Potential Mechanism for Increasing Proso Millet Grain Yield.

Intercropping of cereals and legumes has been used in modern agricultural systems, and the soil microorganisms associated with legumes play a vital role in organic matter decomposition and nitrogen (N) fixation. This study investigated the effect of intercropping on the rhizosphere soil microbial composition and structure and how this interaction affects N absorption and utilization by plants to improve crop productivity. Experiments were conducted to analyze the rhizosphere soil microbial diversity and the relationship between microbial composition and N assimilation by proso millet (Panicum miliaceum L.) and mung bean (Vigna radiata L.) from 2017 to 2019. Four different intercropping row arrangements were evaluated, and individual plantings of proso millet and mung bean were used as controls. Microbial diversity and community composition were determined through Illumina sequencing of 16S rRNA and internal transcribed spacer (ITS) genes. The results indicated that intercropping increased N levels in the soil-plant system and this alteration was strongly dependent on changes in the microbial (bacterial and fungal) diversities and communities. The increase in bacterial alpha diversity and changes in unique operational taxonomic unit (OTU) numbers increased the soil N availability and plant N accumulation. Certain bacterial taxa (such as Proteobacteria) and fungal taxa (such as Ascomycota) were significantly altered under intercropping and showed positive responses to increased N assimilation. The average grain yield of intercropped proso millet increased by 13.9-50.1% compared to that of monoculture proso millet. Our data clearly showed that intercropping proso millet with mung bean altered the rhizosphere soil microbial diversity and community composition; thus, this intercropping system represents a potential mechanism for promoting N assimilation and increasing grain yield.

Isolation and characterization of starch from light yellow, orange, and purple sweet potatoes.

Sweet potato is attracting increased research attention because of its high nutritional value (e.g., carotene, anthocyanin, and minerals) and the wide application of its starch in foods and nonfoods. Herein, eight Chinese sweet potato varieties were investigated in terms of the physicochemical properties of starches. The lightness values of the eight sweet potato starches were higher than 90, which was satisfactory for starch purity. The average molecular weight (MW) and amylopectin average chain length (ACL) of sweet potato starches ranged from 6.93 × 107 g/mol to 16.57 × 107 g/mol and from 21.85% to 23.00%, respectively. Su16 starch with low amylose content and a large amount of short chains exhibited low crystallinity and thermal properties. These results suggested that the molecular structure of amylose and amylopectin was the main influencing factor in determining sweet potato starch physicochemical properties. The swelling power and water solubility of the starches ranged within 20.14-30.51 g/g and 5.28%-11.71% at 95 °C, respectively. Regarding pasting properties, all the starch samples presented high peak viscosity (>5500 cP) and peak temperature (>78 °C), indicating that sweet potato starch can be used as a thickener. All eight sweet potatoes varieties showed great application potential in the food industry.

Low-nitrogen tolerance comprehensive evaluation and physiological response to nitrogen stress in broomcorn millet (Panicum miliaceum L.) seedling.

Developing the new crop varieties with high productivity under low nitrogen (N) input is an important access to facilitate modern agricultural sustainability. In the present study, 20 broomcorn millet (Panicum miliaceum L.) varieties were characterized for their morphological and nutrient parameters to different low N levels in seedling. The results showed that 0.25 mM NH4NO3 was the standard concentration for the evaluation and identification of low-N tolerance. Through pearson's correlation analysis, principal component analysis, and subordinate function analysis, the tolerance of 20 varieties under N stress was evaluated and plant height, root length, shoot biomass, and shoot and root N content were considered as the evaluation system of low-N tolerance. Although leaves photosynthetic capacities and activities of N metabolism related enzymes showed the decreasing tendency to N stress, low-N tolerant varieties had higher activities in both leaves and roots as compared to low-N sensitive varieties. The work provides a reliable and comprehensive method for evaluating low-N tolerance in broomcorn millet and our data elucidate possible physiological adaptive mechanisms by which broomcorn millet tolerates N stress.

Linkages between nutrient ratio and the microbial community in rhizosphere soil following fertilizer management.

To unravel the linkages between ecological ratios (C:N:P) and the microbial community in rhizosphere soil in response to fertilizer management, soil samples were collected from a proso millet (Panicum miliaceum L.) field under different fertilizer management systems, including nitrogen fertilizer (NF), phosphorus fertilizer (PF), combined N and P (NP) fertilizer, and organic fertilizer (OF); no fertilizer (CK) was used as a control. Furthermore, 16S rRNA and ITS gene sequencing were applied to represent the bacterial and fungal diversity in the soil. Moreover, the elemental properties, including the carbon (C), nitrogen (N), and phosphorus (P) contents, in the microbial biomass and rhizosphere soil were evaluated. The results showed that the C, N, and P contents and microbial biomass (MBC, MBN and MBP, respectively) in the rhizosphere soil were augmented following fertilizer management. Increases in the alpha diversity indices (Shannon and Chao 1) of soil bacteria and fungi were observed in response to the fertilizers, and the responses were more closely related to the soil C:N and N:P ratios than to the C:P ratio. Additionally, with high relative abundances (>1%) across all soil samples, the composition of soil microbial phyla levels revealed different trends following fertilizer management. The abundances of Actinobacteria and Gemmatimonadetes increased, while the abundances of Acidobacteria and Nitrospirae decreased (P < 0.05) following fertilizer management. Among the fungal taxa, the abundances of Ascomycota and Mortierellomycota responded positively to fertilizer. These results were largely influenced by changes in the C:N and N:P ratios in both the soil and microbial biomass. Overall, significantly increased C:N and decreased N:P ratios in the soil reflected the N deficiency that would limit increased microbial biomass and diversity. Together, all of these results indicated that interactions between ecological ratios (C:N:P) and microbial community composition play vital roles in resource imbalance in dynamic environments. Thus, N status should be an important factor for sustainable agricultural management. Moreover, the synergistic effects were better with the combination of C, N, and P or with organic fertilizer than with C, N and P separately.

Functional and physicochemical properties of flours and starches from different tuber crops.

Flours and isolated starches from different potato and sweet potato varieties were evaluated for their physical, functional, pasting, and thermal properties. The flours had higher protein and amylose contents than starches. The L values of the starches ranged from 91.92 (S-2) to 96.42 (S-1); thus, the whiteness of the starch samples was satisfactory. X-ray diffraction mode showed that potato starch could be a special material for crystalline nanomaterials with potential industrial applications. The starches had higher viscosity than flours. Therefore, starches can be used as thickeners in different food products. The flours exhibited high gelatinization temperatures but low enthalpy, which can be attributed to the effects of non-starch components in the flours, such as proteins and lipids. Potato flours and starches exhibited higher amylose contents and pasting characteristics and wider applications in the food industry than sweet potato flours and starches. The purple-fleshed varieties had high antioxidant activity. Therefore, the colorful flours of potatoes and sweet potatoes can be combined with other cereals for the development of functional flours with nutritional applications.

Effects of phosphate fertiliser on the physicochemical properties of Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) starch.

Phosphate fertilisation affects the growth, development and quality of Tartary buckwheat. In this study, the effect of different phosphorus levels, including 0, 15, 75, and 135 kg/ha (non-, low-, medium-, and high-phosphorus levels, respectively), on the characteristics of starch from Tartary buckwheat were investigated in 2015 and 2017. With increased phosphorus level, the median diameter of starch granules and the apparent amylose content initially decreased and then increased. All starch samples showed the features of A-type X-ray diffraction patterns. Starches under medium-phosphorus treatment showed higher relative crystallinity than those under non-phosphorus treatment, as well as the highest solubility, gelatinisation enthalpy and transmittance among all starches. Starches under low-phosphorus treatment exhibited higher pasting properties than those under non-phosphorus treatment. This research revealed that phosphorus treatments and year significantly affected the physicochemical properties of Tartary buckwheat starch, and can provide information for the applications of starch in the food and non-food industries.

Comparative analysis of proso millet (Panicum miliaceum L.) leaf transcriptomes for insight into drought tolerance mechanisms.

BACKGROUND: Drought stress is a major abiotic stress that causes huge losses in agricultural production. Proso millet (Panicum miliaceum L.) can efficiently adapt to drought stress and provides important information and gene resources to improve drought tolerance. However, its complex drought-responsive mechanisms remain unclear. RESULTS: Among 37 core Chinese proso millet cultivars, Jinshu 6 (JS6) was selected as the drought-sensitive test material, whereas Neimi 5 (NM5) was selected as the drought-tolerant test material under PEG-induced water stress. After sequencing, 1695 differentially expressed genes (DEGs) were observed in JS6 and NM5 without PEG-induced water stress (JS6CK and NM5CK). A total of 833 and 2166 DEGs were found in the two cultivars under simulated drought by using 20% PEG-6000 for 6 (JS6T6 and NM5T6) and 24 h (JS6T24 and NM5T24), respectively. The DEGs in JS6T6 and JS6T24 treatments were approximately 0.298- and 0.754-fold higher than those in NM5T6 and NM5T24, respectively. Compared with the respective controls, more DEGs were found in T6 treatments than in T24 treatments. A delay in the transcriptional responses of the ROS scavenging system to simulated drought treatment and relatively easy recovery of the expression of photosynthesis-associated genes were observed in NM5. Compared with JS6, different regulation strategies were observed in the jasmonic acid (JA) signal transduction pathway of NM5. CONCLUSION: Under PEG-induced water stress, NM5 maintained highly stable gene expression levels. Compared with drought-sensitive cultivars, the different regulation strategies in the JA signal transduction pathway in drought-tolerant cultivars may be one of the driving forces underlying drought stress tolerance.

Physicochemical Properties of Starches in Proso (Non-Waxy and Waxy) and Foxtail Millets (Non-Waxy and Waxy).

Proso and foxtail millets are widely cultivated due to their excellent resistance to biotic and abiotic stresses and high nutritional value. Starch is the most important component of millet kernels. Starches with different amylose contents have different physicochemical properties. In this study, starches in proso (non-waxy and waxy) and foxtail millets (non-waxy and waxy) were isolated and investigated. All the starch granules had regular polygonal round shapes and exhibited typical "Maltese crosses". These four starches all showed bimodal size distribution. The waxy proso and foxtail millets had higher weight-average molar mass and branching degree and lower average chain length of amylopectin. These four starches all presented A-type crystallinity; however, the relative crystallinity of waxy proso and foxtail millets was higher. The two waxy millets had higher onset temperature, peak temperature, conclusion temperature, and gelatinization enthalpy. However, the two non-waxy millets had higher setback viscosity, peak time, and pasting temperature. The significantly different physicochemical properties of waxy and non-waxy millet starches resulted in their different functional properties.

Analysis of Flavonoid Metabolites in Buckwheat Leaves Using UPLC-ESI-MS/MS.

Flavonoids from plants are particularly important in our diet. Buckwheat is a special crop that is rich in flavonoids. In this study, four important buckwheat varieties, including one tartary buckwheat and three common buckwheat varieties, were selected as experimental materials. The total flavonoid content of leaves from red-flowered common buckwheat was the highest, followed by tartary buckwheat leaves. A total of 182 flavonoid metabolites (including 53 flavone, 37 flavonol, 32 flavone C-glycosides, 24 flavanone, 18 anthocyanins, 7 isoflavone, 6 flavonolignan, and 5 proanthocyanidins) were identified based on Ultra Performance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry (UPLC-ESI-MS/MS) system. Through clustering analysis, principal component analysis (PCA), and orthogonal signal correction and partial least squares-discriminant analysis (OPLS-DA), different samples were clearly separated. Considerable differences were observed in the flavonoid metabolites between tartary buckwheat leaves and common buckwheat leaves, and both displayed unique metabolites with important biological functions. This study provides new insights into the differences of flavonoid metabolites between tartary buckwheat and common buckwheat leaves and provides theoretical basis for the sufficient utilization of buckwheat.

Uniconazole and diethyl aminoethyl hexanoate increase soybean pod setting and yield by regulating sucrose and starch content.

BACKGROUND: Uniconazole (S3307) and diethyl aminoethyl hexanoate (DA-6) are known plant growth regulators (PGRs). However, it is unknown if their regulation of sucrose and starch content can affect pod setting and yield in soybean. Herein, S3307 and DA-6 were foliar sprayed on soybean Hefeng50 and Kangxian6 at the beginning of the bloom cycle in field tests conducted over two years. RESULTS: PGRs promoted the accumulation and distribution of plant biomass and significantly improved leaf photosynthetic rates. Sucrose and starch content increased after PGR treatment across organs and varieties. Accumulation and allocation of sucrose and starch content in soybean source organs are enhanced by PGRs, which supply high levels of assimilate to sink organs. Moreover, sucrose and starch contents in source and sink organs are positively correlated. S3307 and DA-6 also significantly increased pod setting rates and reduced flower and pod abscission rates, leading to increased yield. CONCLUSION: S3307 and DA-6 promoted the accumulation and availability of sucrose and starch content in source organs and increased sucrose and starch content in flowers and pods or seeds, thereby maintaining the balance between source and sink organs and contributing to increased pod setting rates and soybean yield. © 2018 Society of Chemical Industry.