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A study published in the journal iMeta highlights the effectiveness of the CRISPR/Mb2Cas12a genome editing system in cotton plants. The system achieved a high efficiency rate of over 90% at target sites and demonstrated tolerance to different temperatures. It also expanded the editing range in the cotton genome. The study also developed a multiplex genome editing system using Mb2Cas12a, allowing for simultaneous editing of eight target sites. These findings suggest that CRISPR/Mb2Cas12a is a precise and efficient tool for genome editing in cotton plants, which has important implications for cotton breeding and genetic studies. [Extracted from the article]

This study investigates the characteristics of cold events affecting eastern China during November–March of 1979–2018 using station observations and the ERA5 reanalysis, focusing five major cities (Beijing, Zhengzhou, Wuhan, Shanghai and Guangzhou) for their high vulnerability and distinct local thermal conditions than the broader climate regimes. For each city, cold day (CD) (one or more continuous days where the temperature falls below the local 5th percentiles) and cold surge (CS) (a period of 1–3 days with a total temperature decrease exceeding 8°C) were both examined in aspects of occurrence frequency, circulation characteristics and health impacts. Results show that the northern cities are relatively more/less exposed to CD/CS than the southern cities. At all five cities, the two types of events rarely coincide and exhibit distinct multiple‐year variations, as CD and CS are, respectively, dominated by continental‐ and regional‐scale circulations. However, both types of events are associated with the interplay of the East Asia trough at 300 hPa and the Siberian high, Aleutian low and subtropical high at 850 hPa. Results also show that during CDs in these cities, the effective temperatures (ET), which take into account of the near‐surface wind speed and humidity, are often about 5°C lower than the actual temperatures. The ET decreases are larger than the actual temperature drops in most CSs, yet in specific scenarios (primarily in Beijing and Zhengzhou when the temperature drop is relatively small), the ET drop can be less pronounced, as the possible decrease of wind speed and/or humidity can partially mitigate the ET decrease caused by dropping temperatures. These underline the complexity of health impacts of cold events, which vary regionally due to differences in covariations of temperature, wind speed and relative humidity. There aspects are worthy of further investigation. [ABSTRACT FROM AUTHOR]

In monolayer transition metal dichalcogenides, defects, such as chalcogen vacancies, play an important role in determining their properties. Herein, monolayer MoSe2 with varying Se vacancy concentrations is successfully prepared by adjusting the amount of the precursors during the chemical vapor deposition synthesis. The Raman and low‐temperature photoluminescence spectra are systematically studied at varying defect concentrations. Furthermore, it is found that Se vacancies introduce in‐gap electronic states, leading to distinct localized exciton emissions, which can be engineered by controlling the concentration of Se vacancies. Density functional theory calculations indicate that the observed variations in localized exciton emission are attributed to the change of defect level with increasing defect concentration. The results provide insights into the influence of varying Se vacancy concentrations on defect‐induced Raman and PL spectroscopy in MoSe2. [ABSTRACT FROM AUTHOR]

Summary CRISPR‐Cas9 is widely used for genome editing, but its PAM sequence requirements limit its efficiency. In this study, we explore Faecalibaculum rodentium Cas9 (FrCas9) for plant genome editing, especially in rice. FrCas9 recognizes a concise 5′‐NNTA‐3′ PAM, targeting more abundant palindromic TA sites in plant genomes than the 5′‐NGG‐3′ PAM sites of the most popular SpCas9. FrCas9 shows cleavage activities at all tested 5′‐NNTA‐3′ PAM sites with editing outcomes sharing the same characteristics of a typical CRISPR‐Cas9 system. FrCas9 induces high‐efficiency targeted mutagenesis in stable rice lines, readily generating biallelic mutants with expected phenotypes. We augment FrCas9's ability to generate larger deletions through fusion with the exonuclease, TREX2. TREX2‐FrCas9 generates much larger deletions than FrCas9 without compromise in editing efficiency. We demonstrate TREX2‐FrCas9 as an efficient tool for genetic knockout of a microRNA gene. Furthermore, FrCas9‐derived cytosine base editors (CBEs) and adenine base editors (ABE) are developed to produce targeted C‐to‐T and A‐to‐G base edits in rice plants. Whole‐genome sequencing‐based off‐target analysis suggests that FrCas9 is a highly specific nuclease. Expression of TREX2‐FrCas9 in plants, however, causes detectable guide RNA‐independent off‐target mutations, mostly as single nucleotide variants (SNVs). Together, we have established an efficient CRISPR‐FrCas9 system for targeted mutagenesis, large deletions, C‐to‐T base editing, and A‐to‐G base editing in plants. The simple palindromic TA motif in the PAM makes the CRISPR‐FrCas9 system a promising tool for genome editing in plants with an expanded targeting scope. [ABSTRACT FROM AUTHOR]