Grain protein content (GPC) is an important component of rice nutritional quality and influences the physical–chemical properties and taste of cooked rice. Quantitative trait loci (QTLs) for GPC in rice (Oryza sativa L.) were analyzed using chromosome segment substitution lines (CSSLs) developed from 9311 (used as the recipient) and Nipponbare (used as the donor). Using the substitution map strategy, we detected a total of 22 QTLs across all twelve chromosomes except chromosome 1. In addition, 13 QTLs were detected in both years, and 17 QTLs were consistent with previously reported GPC QTLs. Among them, qGPC4, which located between RM6748 and RM348 within the boundary of 30.45–33.95 Mb, was at the same position or flanked by several previous QTLs. qGPC6-1 was mapped to a QTL cluster where the Waxy gene is located. With the same Waxyb alleles of 9311 and Nipponbare, the effect of Waxy on GPC could be removed, and there should exist a true stable GPC QTL near Waxy. Four novel and stable QTLs for GPC were identified in this research. These stable and novel QTLs could serve as candidate genes for future research, and CSSLs are suitable for mapping GPC QTLs in rice note.

Although the newly established constructed wetland-microbial fuel cell (CW-MFC) has attracted considerable attention for wastewater treatment and electricity generation. However, the integration of MFC into CWs always faces a large portion of energy losses due to the existence of higher internal resistances. Here, a novel working strategy for energy harvesting from CW-MFC system, named as capacitor engaged duty cycling (CDC) strategy, was proposed and tested. Results showed that with duty cycle (D) value of 31.58% (D = 31.58%), the effective charge obtained from CDC strategy is 11.9% higher than the conventional continuous loading (CL) mode. Further lower D value to 18.75%, the total charge harvested increased about 17.57%. In addition, CDC operation mode also shows advantages over higher internal resistance system. This operation strategy has the potential to minimize the energy losses with a suitable D value. Overall, this method showed a simple but effectively way to maximize the energy harvesting from CW-MFC system.

The aim of this study was to analyze the biochemical and molecular responses of suspension cells of transgenic rice (Oryza sativa L.) over-expressing the maize C 4 -pepc gene encodes phosphoenolpyruvate carboxylase (PEPC) (PC line) to drought stress by exogenous ATP. Suspension cells of PC and wild-type (WT) rice cultured in N6 basic medium were subjected to the following treatments: a 24-h drought treatment imposed by 20% (m/v) polyethylene glycol 6000 (PEG6000 treatment); an exogenous adenosine 5′-triphosphate treatment (ATP; 1 mmol L−1); and a combined exogenous ATP + PEG6000 treatment. We measured DNA fragmentation, cell viability, lipid peroxidation, antioxidant enzyme activities, PEPC activity, ATP content, and the levels of Ca2+, H2O2, and NO using spectrophotometric methods and fluorescent dyes, and quantified the transcript levels of stress-related genes such as NAC1 (one of the transcription factors from NAC (NAM/ATAF/CUC) family), cytochrome P450 (P450) and programmed cell death (PCD) under these treatments. Compared with WT cells, PC cells showed more stable cellular activity, lower lipid peroxidation, enhanced antioxidant enzyme activity, higher levels of endogenous ATP level, PEPC activity, and transcript levels of C 4 -pepc and the transcription factor NAC1 under drought stress. While the content of H2O2 and the transcript levels of P450 and PCD were decreased and kept at the low levels during the same treatments. Adding ATP, PC reinforced these early signaling effects response to PEG6000 treatment. Based on the results, the exogenous ATP triggers a series of signaling cascade reactions for enhancing antioxidant protection in PC cells during the drought treatment, conferring to the drought-tolerance.

Grain size is an important trait that directly influences rice yield. The qGL3 and GS3 genes are two putative regulators that play a role in grain size determination. A single rare nucleotide substitution (C→A) at position 1092 in exon 10 of qGL3 might be responsible for variations in grain size. However, little is known about the haplotype variations of qGL3 and their interactions with GS3 during the regulation of grain length and grain weight. In this study, qGL3 haplotype variations were examined in 61 Indica varieties, and the effects of qGL3 and GS3 on grain trait variation in 110 lines were evaluated. Six qGL3 haplotypes were identified, and qGL3-2 was a major haplotype in Indica varieties. Moreover, qGL3-6, a reported key single nucleotide polymorphism, was validated. Our results showed that the mutants qgl3 and gs3 (loss-of-function mutation types of qGL3 and GS3, respectively) had significant effects on grain length and grain weight. However, no significant effects associated with differences in the regulation of grain thickness were observed. The genetic effects of qgl3 on grain phenotypes were stronger than those of gs3. In addition to increased grain length, qgl3 had an evident role in grain width increases. In contrast, gs3 played an opposite role in grain width regulation. These results provided novel insights into grain size control and the functions of qgl3 and gs3 in rice yield improvement.

Panicle exsertion (PE) is an important morphological trait that is closely associated with spikelet fertility and grain yield. To understand the genetic basis of PE and its relationships with yield and yield-related traits, a recombinant inbred population consisting of 240 lines derived from a cross between an Indica cultivar 'Kasalath' and a Japonica germplasm 'TD70', was studied over two years. PE was significantly correlated with plant height, heading date (HD), panicle length (PL), and panicle characteristics such as primary branch number, spikelet number per panicle, and spikelet density, but showed poor correlation with yield components. Based on linkage mapping of 141 SSR markers, a total of 38 quantitative trait loci (QTLs) were located for 12 investigated traits, with the contribution varying from 6.51 to 8.61%. Among these, four QTL clusters were identified on chromosomes 1, 2, 3, and 6, suggesting the existence of pleiotropic alleles. In some intervals, two loci for PE were collocated with several traits, which is consistent with the correlations observed with phenotypic variations. The PE QTLs with 'Kasalath' alleles and without pleiotropic effects would be valuable for the improvement of PE in 'TD70' and in other rice varieties.

The AgCl/PMMA nano-composite was prepared by polymerization of MMA in site through reverse micro-emulsion as template, in which the methyl methacrylate(MMA) was designated as oily phase instead of non-reactive functional group solvents. The advantage of this method is that nanocomposite are prepared without the process of modification of nano-particles with organic substances and dispersing them in the matrix. TEM shows that the particle size of nano-AgCl is 20 similar to 80 nm, and the scanning electron microscope (SEM) shows that nano-AgCl is dispersed in the PMMA. FTIR spectrum reveals that the micro-environment of H2O and carboxyl group has changed after the polymerization of MMA, which indicates that the interaction of nano-particle with polymer exists. DMTA spectrum results show that there is strong interaction of nano-particles with polymer chains, which restricts the mobility of polymer chains and forms an interphase layer. Ripening process affects the interaction of polymer with nano-particles. At the higher temperature ripening process, the interphase layer is overlapped and forms a continuous phase. DMTA reveals that the aqueous phase layer around the nano-particles does not apparently affect the interaction of polymer with the nano-particles and the nano-particles acts as a cross-linker in the nanocomposite.