A spontaneous thermo-sensitive female sterility mutation in rice enables fully mechanized hybrid breeding.

Male sterility enables hybrid crop breeding to increase yields and has been extensively studied. But thermo-sensitive female sterility, which is an ideal property that may enable full mechanization in hybrid rice breeding, has rarely been investigated due to the absence of such germplasm. Here we identify the spontaneous thermo-sensitive female sterility 1 (tfs1) mutation that confers complete sterility under regular/high temperature and partial fertility under low temperature as a point mutation in ARGONAUTE7 (AGO7). AGO7 associates with miR390 to form an RNA-Induced Silencing Complex (RISC), which triggers the biogenesis of small interfering RNAs (siRNAs) from TRANS-ACTING3 (TAS3) loci by recruiting SUPPRESSOR OF GENE SILENCING (SGS3) and RNA-DEPENDENT RNA POLYMERASE6 (RDR6) to TAS3 transcripts. These siRNAs are known as tasiR-ARFs as they act in trans to repress auxin response factor genes. The mutant TFS1 (mTFS1) protein is compromised in its ability to load the miR390/miR390* duplex and eject miR390* during RISC formation. Furthermore, tasiR-ARF levels are reduced in tfs1 due to the deficiency in RDR6 but not SGS3 recruitment by mTFS1 RISC under regular/high temperature, while low temperature partially restores mTFS1 function in RDR6 recruitment and tasiR-ARF biogenesis. A miR390 mutant also exhibits female sterility, suggesting that female fertility is controlled by the miR390-AGO7 module. Notably, the tfs1 allele introduced into various elite rice cultivars endows thermo-sensitive female sterility. Moreover, field trials confirm the utility of tfs1 as a restorer line in fully mechanized hybrid rice breeding.

Tuning the Electronic Structure of ZnO Bilayer: A First-Principles Study.

In this study, a ZnO bilayer is modeled, and the electronic structure is investigated by a first-principles calculation. Unlike a ZnO monolayer, the Zn and O atoms in the same layer of a ZnO bilayer have a small difference in the z coordinate, which is attributed to both intralayer and interlayer actions. An external electric field perpendicular to the basal plane causes a low-buckled structure of the bilayer, and the deformation increases with the E-field. The electronic structure of the ZnO bilayer can also be tuned by the E-field. Charge transfer increases between the upper and the lower layers, and the bilayer shows more metallicity when the E-field increases. The present study can help us understand more about the electronic structures of ZnO materials for potential applications in electronics and optoelectronics.

Working capital management, corporate performance, and strategic choices of the wholesale and retail industry in China.

We examine the influence of strategic choice on working capital configurations and observe how the relationship between working capital ratio and operational performance differs depending on strategy. By clustering the strategic factors of the wholesale and retail industry, we find three categories of strategies: terminal market strategy, middle market strategy, and hybrid strategy. Using the panel data of the listed companies of the wholesale and retail industry as our sample, we analyze the differences in the ways companies configure working capital, the speed with which working capital adjusts to its target, and the effects of working capital on performance for companies that make different strategic choices. The empirical results suggest that working capital is configured and adjusted to its target in different ways under different competitive strategic choices. This effect is finally transferred to influence the relationship between working capital configuration and operational performance.