The Sulfoquinovosyltransferaselike Enzyme SQD2.2 is Involved in Flavonoid Glycosylation, Regulating Sugar Metabolism and Seed Setting in Rice

Seed setting is an important trait that contributes to seed yield and relies greatly on starchaccumulation. In this study, a sulfoquinovosyl transferase-like protein, designated as SQD2.2involved in seed setting and flavonoid accumulation, was identified and characterized in rice.Rice SQD2.2 is localized to the cytoplasm, and the SQD2.2 transcript was highest in leaves. RiceSQD2.2-overexpressing (OE) plants exhibited a decreased seed setting rate and diminished tillernumber simultaneously with an increased glycosidic flavonoid level compared with wild-type(WT) plants. SQD2.2 catalyzes the glycosylation of apigenin to produce apigenin 7-O-glucosideusing uridine diphosphate-glucose (UDPG) as a sugar donor, but it failed to compensate forsulfoquinovosyldiacylglycerol (SQDG) synthesis in the Arabidopsis sqd2 mutant. Furthermore,apigenin 7-O-glucoside inhibited starch synthase (SS) activity in a concentration-dependent manner,and SQD2.2-OE plants exhibited reduced SS activity accompanied by a significant reduction in starchlevels and an elevation in soluble sugar levels relative to WT plants. Both adenosine diphosphateglucose (ADPG) and UDPG levels in SQD2.2-OE plants were notably lower than those in WT plants.Taken together, rice SQD2.2 exhibits a novel role in flavonoid synthesis and plays an important role inmediating sugar allocation between primary and secondary metabolism in rice

Optimal Investment Timing and Size of a Logistics Park: A Real Options Perspective

This paper uses a real options approach to address optimal timing and size of a logistics park investment with logistics demand volatility. Two important problems are examined: when should an investment be introduced, and what size should it be? A real option model is proposed to explicitly incorporate the effect of government subsidies on logistics park investment. Logistic demand that triggers the threshold for investment in a logistics park project is explored analytically. Comparative static analyses of logistics park investment are also carried out. Our analytical results show that (1) investors will select smaller sized logistics parks and prepone the investment if government subsidies are considered; (2) the real option will postpone the optimal investment timing of logistics parks compared with net present value approach; and (3) logistic demands can significantly affect the optimal investment size and timing of logistics park investment

Ammonia Volatilization Reduced by Combined Application of Biogas Slurry and Chemical Fertilizer in Maize–Wheat Rotation System in North China Plain

Digestate and biogas slurry (BS) are the byproduct of biogas engineering that could be used for elevating plant growth. However, the consequent emissions of ammonia from BS are considered a severe threat to the atmosphere. Herein, we conducted two consecutive field experiments with wheat–maize rotations to find out the optimum ratio of BS to combine with chemical fertilizer (CF) to reduce ammonia volatilization (AV) while keeping the stable crop yield. In maize season, 226.5 kg N/ha of CF was applied. In wheat season, 226.5 kg N/ha was applied at different ratios (100%, 80%, and 50%) between BS and CF. Our results found that the maximum yield of 6250 kg/ha was produced by CF, and this yield could be obtained through a combined application of 38% BS mixed with CF. Highest AV produced of 16.08 kg/ha by CF. BS treatments significantly reduced the emission from 18% to 32% in comparison to CF. The combined application of BS-CF produced the highest yield due to essential nutrients coming from both BS-CF. Subsequently, it reduced the AV depending on fertilizer type and fertilizer rate. An optimal ratio of 38% BS was recommended to produce the highest yield and lowest ammonia emissions. The application of BS together with different ratios of CF could be an alternative agricultural strategy to obtain desired crop yield and reduce AV in North China Plain (NCP)

Dual Activities of Plant cGMP-Dependent Protein Kinase and its Roles in Gibberellin Signaling and Salt Stress.

Cyclic GMP (cGMP) is an important regulator in eukaryotes, and cGMP-dependent protein kinase (PKG) plays a key role in perceiving cellular cGMP in diverse physiological processes in animals. However, the molecular identity, property, and function of PKG in plants remain elusive. In this study, we have identified PKG from plants and characterized its role in mediating the gibberellin (GA) response in rice (Oryza sativa). PKGs from plants are structurally unique with an additional type 2C protein phosphatase domain. Rice PKG possesses both protein kinase and phosphatase activities, and cGMP stimulates its kinase activity but inhibits its phosphatase activity. One of PKG’s targets is GAMYB, a transcription factor in GA signaling, and the dual activities of PKG catalyze the reversible phosphorylation of GAMYB at Ser6 and modulate the nucleocytoplasmic distribution of GAMYB in response to GA. Loss of PKG impeded the nuclear localization of GAMYB and abolished GAMYB function in the GA response, leading to defects in GA-induced seed germination, internode elongation, and pollen viability. In addition to GAMYB, PKG has multiple potential targets and thus has broad effects, particularly in the salt stress response

Genomic insights into the evolution of flavonoid biosynthesis and O-methyltransferase and glucosyltransferase in Chrysanthemum indicum

Summary: Flavonoids are a class of secondary metabolites widely distributed in plants. Regiospecific modification by methylation and glycosylation determines flavonoid diversity. A rare flavone glycoside, diosmin (luteolin-4′-methoxyl-7-O-glucosyl-rhamnoside), occurs in Chrysanthemum indicum. How Chrysanthemum plants evolve new biosynthetic capacities remains elusive. Here, we assemble a 3.11-Gb high-quality C. indicum genome with a contig N50 value of 4.39 Mb and annotate 50,606 protein-coding genes. One (CiCOMT10) of the tandemly repeated O-methyltransferase genes undergoes neofunctionalization, preferentially transferring the methyl group to the 4′-hydroxyl group of luteolin with ortho-substituents to form diosmetin. In addition, CiUGT11 (UGT88B3) specifically glucosylates 7-OH group of diosmetin. Next, we construct a one-pot cascade biocatalyst system by combining CiCOMT10, CiUGT11, and our previously identified rhamnosyltransferase, effectively producing diosmin with over 80% conversion from luteolin. This study clarifies the role of transferases in flavonoid diversity and provides important gene elements essential for producing rare flavone

Flexible and Lightweight Fuel Cell with High Specific Power Density

Flexible devices have been attracting great attention recently due to their numerous advantages. But the energy densities of current energy sources are still not high enough to support flexible devices for a satisfactory length of time. Although proton exchange membrane fuel cells (PEMFCs) do have a high-energy density, traditional PEMFCs are usually too heavy, rigid, and bulky to be used in flexible devices. In this research, we successfully invented a light and flexible air-breathing PEMFC by using a new design of PEMFC and a flexible composite electrode. The flexible air-breathing PEMFC with 1 × 1 cm² working area can be as light as 0.065 g and as thin as 0.22 mm. This new PEMFC exhibits an amazing specific volume power density as high as 5190 W L^–1, which is much higher than traditional (air-breathing) PEMFCs. Also outstanding is that the flexible PEMFC retains 89.1% of its original performance after being bent 600 times, and it retains its original performance after being dropped five times from a height of 30 m. Moreover, the research has demonstrated that when stacked, the flexible PEMFCs are also useful in mobile applications such as mobile phones. Therefore, our research shows that PEMFCs can be made light, flexible, and suitable for applications in flexible devices. These innovative flexible PEMFCs may also notably advance the progress in the PEMFC field, because flexible PEMFCs can achieve high specific power density with small size, small volume, low weight, and much lower cost; they are also much easier to mass produce

Additional file 2 of Pyramiding of Low Chalkiness QTLs Is an Effective Way to Reduce Rice Chalkiness

Supplementary Material 2: Table S1 QTLs for PGC and their position in the substitution segments in SSSLs. Table S2 Substitution segments carrying QTLs for PGC in pyramiding lines. Table S3 The phenotypes of rice chalkiness in 1QLs to 4QLs. Table S4 Additive effects of QTL combinations on PGC in 1QLs to 4QLs. Table S5 Epistatic effects of QTL combinations on PGC in pyramiding lines. Table S6 Average temperatures of 30 days after rice flowering in different cropping season