Identification of quantitative trait loci conferring resistance to tan spot in a biparental population derived from two Nebraska hard red winter wheat cultivars

Tan spot, caused by Pyrenophora tritici-repentis (Ptr), is a destructive foliar disease in all types of cultivated wheat worldwide. Genetics of tan spot resistance in wheat is complex, involving insensitivity to fungal-produced necrotrophic effectors (NEs), major resistance genes, and quantitative trait loci (QTL) conferring race-nonspecific and race-specific resistance. The Nebraska hard red winter wheat (HRWW) cultivar ‘Wesley’ is insensitive to Ptr ToxA and highly resistant to multiple Ptr races, but the genetics of resistance in this cultivar is unknown. In this study, we used a recombinant inbred line (RIL) population derived from a cross between Wesley and another Nebraska cultivar ‘Harry’ (Ptr ToxA sensitive and highly susceptible) to identify QTL associated with reaction to tan spot caused by multiple races/isolates. Sensitivity to Ptr ToxA conferred by the Tsn1 gene was mapped to chromosome 5B as expected. The Tsn1 locus was a major susceptibility QTL for the race 1 and race 2 isolates, but not for the race 2 isolate with the ToxA gene deleted. A second major susceptibility QTL was identified for all the Ptr ToxC-producing isolates and located to the distal end of the chromosome 1A, which likely corresponds to the Tsc1 locus. Three additional QTL with minor effects were identified on chromosomes 7A, 7B, and 7D. This work indicates that both Ptr ToxA-Tsn1 and Ptr ToxC-Tsc1 interactions are important for tan spot development in winter wheat, and Wesley is highly resistant largely due to the absence of the two tan spot sensitivity genes.     

Reducing Mg Anode Overpotential via Ion Conductive Surface Layer Formation by Iodine Additive

Electrolytes that are able to reversibly deposit/strip Mg are crucial for rechargeable Mg batteries. The most studied complex electrolytes based on Lewis acid‐base chemistry are expensive, difficult to be synthesized, and show limited anodic stability. Conventional electrolytes using simple salts such as Mg(TFSI)₂ can be readily synthesized, but Mg deposition/stripping in these simple salt electrolytes is accompanied by a large overpotential due to the formation of a surface layer on the Mg metal with a low Mg ion conductivity. Here the overpotential for Mg deposition/stripping in a simple salt, Mg(TFSI)₂‐1,2‐dimethoxyethane (DME), electrolyte is significantly reduced by adding a small concentration of iodine (≤50 × 10^?3m ) as an additive. Mechanism studies demonstrate that an Mg ion conductive solid MgI₂ layer is formed on the surface of the Mg metal and acts as a solid electrolyte interface. With the Mg(TFSI)₂‐DME‐I₂ electrolyte, a very small voltage hysteresis is achieved in an Mg‐S full cell.     

Efficient Organic Solar Cells with Extremely High Open‐Circuit Voltages and Low Voltage Losses by Suppressing Nonradiative Recombination Losses

One of the most important factors that limits the efficiencies of bulk‐heterojunction organic solar cells (OSCs) is the modest open‐circuit voltage (V_oc) due to their large voltage loss (V_loss) caused by significant nonradiative recombination loss. To boost the performance of OSCs toward their theoretical limit, developing high‐performance donor: acceptor systems featuring low V_loss with suppressed nonradiative recombination losses (<0.30 V) is desired. Herein, high performance OSCs based on a polymer donor benzodithiophene‐difluorobenzoxadiazole‐2‐decyltetradecyl (BDT‐ffBX‐DT) and perylenediimide‐based acceptors (PDI dimer with spirofluorene linker (SFPDI), PDI4, and PDI6) are reported which offer a high power conversion efficiency (PCE) of 7.5%, 56% external quantum efficiency associated with very high V_oc (>1.10 V) and low V_loss (<0.60 V). A high V_oc up to 1.23 V is achieved, which is among the highest values reported for OSCs with a PCE beyond 6%, to date. These attractive results are benefit from the suppressed nonradiative recombination voltage loss, which is as low as 0.20 V. This value is the lowest value for OSCs so far and is comparable to high performance crystalline silicon and perovskite solar cells. These results show that OSCs have the potential to achieve comparable V_oc and voltage loss as inorganic photovoltaic technologies.     

Structural insights into Rhino‐Deadlock complex for germline piRNA cluster specification

PIWI‐interacting RNAs (piRNAs) silence transposons in germ cells to maintain genome stability and animal fertility. Rhino, a rapidly evolving heterochromatin protein 1 (HP1) family protein, binds Deadlock in a species‐specific manner and so defines the piRNA‐producing loci in the Drosophila genome. Here, we determine the crystal structures of Rhino‐Deadlock complex in Drosophila melanogaster and simulans. In both species, one Rhino binds the N‐terminal helix–hairpin–helix motif of one Deadlock protein through a novel interface formed by the beta‐sheet in the Rhino chromoshadow domain. Disrupting the interface leads to infertility and transposon hyperactivation in flies. Our structural and functional experiments indicate that electrostatic repulsion at the interaction interface causes cross‐species incompatibility between the sibling species. By determining the molecular architecture of this piRNA‐producing machinery, we discover a novel HP1‐partner interacting mode that is crucial to piRNA biogenesis and transposon silencing. We thus explain the cross‐species incompatibility of two sibling species at the molecular level.     

Ectopic expression of a novel OsExtensin‐like gene consistently enhances plant lodging resistance by regulating cell elongation and cell wall thickening in rice

Plant lodging resistance is an important integrative agronomic trait of grain yield and quality in crops. Although extensin proteins are tightly associated with plant cell growth and cell wall construction, little has yet been reported about their impacts on plant lodging resistance. In this study, we isolated a novel extensin‐like (OsEXTL) gene in rice, and selected transgenic rice plants that expressed OsEXTL under driven with two distinct promoters. Despite different OsEXTL expression levels, two‐promoter‐driven OsEXTL‐transgenic plants, compared to a rice cultivar and an empty vector, exhibited significantly reduced cell elongation in stem internodes, leading to relatively shorter plant heights by 7%–10%. Meanwhile, the OsEXTL‐transgenic plants showed remarkably thickened secondary cell walls with higher cellulose levels in the mature plants, resulting in significantly increased detectable mechanical strength (extension and pushing forces) in the mature transgenic plants. Due to reduced plant height and increased plant mechanical strength, the OsEXTL‐transgenic plants were detected with largely enhanced lodging resistances in 3 years field experiments, compared to those of the rice cultivar ZH11. In addition, despite relatively short plant heights, the OsEXTL‐transgenic plants maintain normal grain yields and biomass production, owing to their increased cellulose levels and thickened cell walls. Hence, this study demonstrates a largely improved lodging resistance in the OsEXTL‐transgenic rice plants, and provides insights into novel extensin functions in plant cell growth and development, cell wall network construction and wall structural remodelling.     

Up-Regulation of Cdc37 Contributes to Schwann Cell Proliferation and Migration After Sciatic Nerve Crush

Cell division cycle protein 37 (Cdc37), a molecular chaperone takes part in a series of cellular processes including cell signal transduction, cell cycle progression, cell proliferation, cell motility, oncogenesis and malignant progression. It can not only recruit immature protein kinases to HSP90 but also work alone. Cdc37 was reported to be associated with neurogenesis, neurite outgrowth, axon guidance and myelination. However, the roles of Cdc37 on Schwann cells (SC) after peripheral nerve injury (PNI) remain unknown. In this study, we found that the expression of Cdc37 increased and reached the peak at 1 week after sciatic nerve crush (SNC), which was consistent with that of proliferation cell nuclear antigen. Immunofluorescence verified that Cdc37 co-localized with SC in vivo and in vitro. Intriguingly, Cdc37 protein level was potentiated in the model of TNF-α-induced SC proliferation. Moreover, we found that Cdc37 silencing impaired proliferation of SC in vitro. Moreover, Cdc37 suppression attenuated kinase signaling pathways of Raf–ERK and PI3K/AKT which are crucial cell signaling for SC proliferation. Finally, we found that Cdc37 silencing inhibited SC migration in vitro. In conclusion, we demonstrated that the way Cdc37 contributed to SC proliferation is likely via activating kinase signaling pathways of Raf–ERK and PI3K/AKT, and CDC37 was also involved in SC migration after SNC.     

A systematic investigation of leaf epidermis in <Emphasis Type="Italic">Camellia</Emphasis> using light microscopy

The characters of mature leaf epidermis of 58 species and 3 varieties belonging to 19 sections, representing all the 4 subgenera: Protocamellia, Camellia, Thea and Metacamellia were investigated under light microscope. The main conclusions are as follows: 1) The shape of the epidermal cells is elliptical, polygonal or irregular and the anticlinal walls are arched, straight or sinuolate, sinuous to sinuate. 2) The stomatal apparatus, consisting of a stoma (a pore plus a pair of guard cells) and 3–4 subsidiary cells, restricted to the abaxial surface of the leaves, were assigned to anisocytic, anisotricytic, isotricytic or tetracytic type. 3) Special structures in leaf epidermis, such as stomatal clusters, aborted stomata, secretory cells, cuticular intrusions and their taxonomic implications were also elucidated.