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The juvenile‐to‐adult transition in plants involves changes in vegetative growth and plant architecture; the timing of this transition has important implications for agriculture. The microRNA miR156 regulates this transition and shoot maturation in plants. In Arabidopsis thaliana, deposition of histone H3 trimethylation on lysine 27 (H3K27me3, a repressive mark) at the MIR156A/C loci is regulated by Polycomb Repressive Complex 1 (PRC1) or PRC2, depending on the developmental stage. The levels of miR156 progressively decline during shoot maturation. The amount of H3K27me3 at MIR156A/C loci affects miR156 levels; however, whether this epigenetic regulation is conserved remains unclear. Here, we found that in rice (Oryza sativa), the putative PRC1 subunit LIKE HETEROCHROMATIN PROTEIN 1 (OsLHP1), with the miR156–SQUAMOSA PROMOTER BINDING PROTEIN‐LIKE (SPL) module, affects developmental phase transitions. Loss of OsLHP1 function results in ectopic expression of MIR156B/C/I/E, phenocopy of miR156 overexpression, and reduced H3k27me3 levels at MIR156B/C/I/E. This indicates that OsLHP1 has functionally diverged from Arabidopsis LHP1. Genetic and transcriptome analyses of wild‐type, miR156b/c‐overexpression, and Oslhp1‐2 mutant plants suggest that OsLHP1 acts upstream of miR156 and SPL during the juvenile‐to‐adult transition. Therefore, modifying the OsLHP1–miR156–SPL pathway may enable alteration of the vegetative period and plant architecture. [ABSTRACT FROM AUTHOR]

Genetic erosion refers to the loss of genetic variation in a crop. In China, only a few original landraces of rice (Oryza sativa) were used in breeding and these became the primary genetic background of modern varieties. Expanding the genetic diversity among Chinese rice varieties and cultivating high-yielding and high-quality varieties with resistance to different biotic and abiotic stresses is critical. Here, we used the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein9(Cas9) genome editing system to edit Semi-Dwarf1 (SD1) in the elite landraces Kasalath and TeTePu (TTP), which contain many desired agronomic traits such as tolerance to low phosphorous and broad-spectrum resistance to several diseases and insects. Mutations of SD1 confer shorter plant height for better resistance to lodging. Field trials demonstrated that the yield of the new Kasalath and TTP mutant lines was better than that of the wild type under modern cultivation and that the lines maintained the same desirable agronomic characteristics as their wild-type progenitors. Our results showed that breeding using available landraces in combination with genomic data of different landraces and gene-editing techniques is an effective way to relieve genetic erosion in modern rice varieties. [ABSTRACT FROM AUTHOR]

Abstract GA is important for rice seed germination, and seed embryo growth relies on sugar supplementation via starch hydrolysis in the endosperm. Low temperature reduces the seed germination rates of rice; however, the mechanism of GA metabolism and its impact on sugar utilization of germinating seeds under low temperature conditions remain poorly understood. In this study, low-temperature (15 °C) treatment delayed rice (Oryza sativa L.) seed germination, promoted GA deactivation, inhibited GA signal transduction, and increased ABA synthesis in the seed compared with normal treatment (30 °C). Under low temperature conditions, the soluble sugar content in endosperm was reduced along with depression of the specific activity levels of α-amylase (EC 3.2.1.1) and β-amylase (EC 3.2.1.2), but the soluble sugar content was increased in the embryo compared with the control treatment. Low temperature treatment promoted sugar transportation from endosperm to embryo and reduced the activity levels of enzymes involved in glycolysis and the tricarboxylic acid cycle, which participated in sugar consumption. Exogenous GA 3 application (10 μM) prompted GA signal transduction and inhibited ABA synthesis, while enhancing starch hydrolysis and sugar consumption to boost rice seed germination under low temperature conditions. In conclusion, a deficiency of bioactive GAs in rice seeds exposed to low temperature led to a decrement in starch hydrolysis and sugar consumption, thus inhibit seed germination. Highlights • Low temperature promoted GA deactivation to inhibit seed germination. • Low temperature altered sugar accumulation between endosperm and embryo. • GA deactivation inhibited starch hydrolysis in endosperm at a low temperature. • Low temperature promoted sugar transportation from endosperm to embryo. • GA deactivation led to sugar consumption decrement in embryo at a low temperature. [ABSTRACT FROM AUTHOR]

Bismuth-layer-structured (Ba 1−xMn x)Bi 4Ti 4O 15 (0.0 ≤  x ≤ 0.8) ceramics were prepared by a Sol–Gel method. The effects of the amount of Mn-doped on the phase structure, the dielectric as well as piezoelectric properties of BaBi 4Ti 4O 15 ceramics were studied. The X-ray diffraction results revealed that the introduction of Mn resulting in distortion of lattice, which contributes to the crystallization of the layered structure grains. The densification, dielectric and piezoelectric properties of the (Ba 1−xMn x)Bi 4Ti 4O 15 ceramics were significantly promoted by the Mn substitution of Ba. When the value of doping amount Mn is 0.4, the (Ba 0.6Mn 0.4)Bi 4Ti 4O 15 ceramic exhibited a high piezoelectric constant ( d33 = 7.5 pC/N), a big relatively dielectric constant ( εr = 764.26) and a small dielectric loss (tan δ = 0.0124). [ABSTRACT FROM AUTHOR]

Two new rod‐packing metal–organic frameworks (RPMOF) are constructed by regulating the in situ formation of the capping agent. In CPM‐s7, carboxylate linkers extend 1D manganese‐oxide chains in four additional directions, forming 3D RPMOF. The substitution of Mn2+ with a stronger Lewis acidic Co2+, leads to an acceleration of the hydrolysis‐prone sulfonate linker, resulting in presence of sulfate ions to reduce two out of the four carboxylate‐extending directions, and thus forming a new 2D rod‐packing CPM‐s8. Density functional theory calculations and magnetization measurements reveal ferrimagnetic ordering of CPM‐s8, signifying the potential of exploring 2D RPMOF for effective low‐dimensional magnetic materials. [ABSTRACT FROM AUTHOR]

Lanthanum strontium ferrite (La 1−xSr xFeO 3, x = 0.1, 0.3, 0.5, 0.7) (LSF) films were prepared on platinized/silica/silicon (Pt/SiO 2/Si) substrates by a sol–gel method. The crystallization, surface morphology and dielectric properties of the LSF films have been studied. Among the samples, La 0.5Sr 0.5FeO 3 thin film have the most homogeneous, smooth surface and the best dielectric properties ( εr = 2881.58, tanδ = 1.20) at the frequency of 1 kHz. Mn-doping ( y) in La 0.5Sr 0.5FeO 3 further improves the dielectric properties ( εr = 2922.91, tanδ = 1.11) of the film. Both εr and tanδ values of the Mn-doped ( y = 0.02) La 0.5Sr 0.5FeO 3 films decreases with increasing the frequency. The biggest εr value is 3238.18 at the frequence of 0.02 kHz. [ABSTRACT FROM AUTHOR]

Chloroplast is a crucial organelle for plant photosynthesis and maintaining normal life activities in higher plants. Although some genes related to chloroplast development and pigment synthesis have been identified or cloned in rice, little is known about the relationship between these genes and abiotic stress response. In this study, we identified a novel mutant white stripe leaf 12 (wsl12) affecting pigment synthesis, chloroplast development and abiotic stress response in rice. The mutant phenotype was obvious at seeding and tillering stages and in response to the temperature change. Genetic analysis of reciprocal crosses between wsl12 and wild-type plants showed that wsl12 was a recessive mutant in a single nuclear locus. Map-based cloning revealed that the WSL12 locus encoded OsNDPK2, one of the three nucleoside diphosphate kinases (OsNDPKs). WSL12 expressed in all tested tissues, while it highly expressed in leaves and young tissues. The WSL12 protein localized to the chloroplast. The wsl12 mutant showed higher superoxide anion level and enhanced sensitivity to abscisic acid (ABA) and salinity. The transcription pattern of many genes involved in chlorophyll biosynthesis, ABA synthesis, light signaling pathway, reactive oxygen species-scavenging pathway and the other two OsNDPKs was altered in the wsl12 mutant. These results indicate that the OsNDPK2 encoded by WSL12 plays an important role in chloroplast development and chlorophyll biosynthesis by regulating the expression levels of related genes. In addition, WSL12 also affects the response to abiotic stress, such as ABA and salinity in rice, and is beneficial to molecular breeding of stress tolerance. [ABSTRACT FROM AUTHOR]

Background: In rice (Oryza sativa) and other grains, weak growth (dwarfism, short panicle length, and low seed-setting rate) and early senescence lead to reduced yield. The molecular mechanisms behind these processes have been widely studied; however, the complex genetic regulatory networks controlling growth and senescence require further elucidation. Results: We isolated a mutant exhibiting weak growth throughout development and early senescence of leaf tips, and designated this mutant weakness and leaf senescence5 (wls5). Histological analysis showed that the poor growth of wls5 plants involved a reduction in cell length and number. Physiological analysis and transmission electron microscopy revealed that the wls5 cells had abnormal chloroplasts, and the mutants underwent chlorophyll degradation triggered by accumulation of reactive oxygen species. Consistent with this, RNA sequencing revealed changes in senescence-related gene expression in wls5 plants. The wls5 mutants also exhibited significantly higher stomatal density and altered phytohormone contents compared with wild-type plants. Fine mapping delimited WLS5 to a 29-kb region on chromosome 5. DNA sequencing of wls5 identified a 3-bp deletion in the first exon of LOC_Os05g04900, resulting in a deletion of a lysine in the predicted protein. Knockout of LOC_Os05g04900 in Nipponbare plants caused leaf senescence, confirming this locus as the causal gene for WLS5. Conclusions: We identified a novel mutant (wls5) that affects plant development and leaf senescence in rice. LOC_Os05g04900, encoding a protein of unknown function, is the causal gene for wls5. Further molecular study of WLS5 will uncover the roles of this gene in plant growth and leaf senescence. [ABSTRACT FROM AUTHOR]