DNA cytosine methylation dynamics and functional roles in horticultural crops

Methylation of cytosine is a conserved epigenetic modification that maintains the dynamic balance of methylation in plants under the regulation of methyltransferases and demethylases.In recent years,the study of DNA methylation in regulating the growth and development of plants and animals has become a key area of research.This review describes the regulatory mechanisms of DNA cytosine methylation in plants.It summarizes studies on epigenetic modifications of DNA methylation in fruit ripening,development,senescence,plant height,organ size,and under biotic and abiotic stresses in horticultural crops.The review provides a theoretical basis for understanding the mechanisms of DNA methylation and their relevance to breeding,genetic improvement,research,innovation,and exploitation of new cultivars of horticultural crops.

Pollen-like self-supported FeIr alloy for improved hydrogen evolution reaction in acid electrolyte

Ir is recognized as efficient catalyst for hydrogen evolution reaction(HER).The high price,however,has hindered its application in the production of hydrogen.In this work,we prepared the self-supported FeIr alloy nanoparticles,taking advantage of solid-state synthesis method.The as-prepared FeIr alloy possesses a novel morphology of pollen,which is consist of smaller FeIr nanoparticles.DFT calculations reveal that the change of the free Gibbs for Ir is negative after the adsorption of active H,while it is positive for the case of Fe.Thus,the alloying of Fe and Ir not only effectively reduces the cost,but also can achieve more adequate adsorption of active H species.Benefitting from this,the as-prepared FeIr alloy nanoparticle exhibits superior HER performance with an overpotential of 19 m V at a current density of 10 m V/cm^(2)and a Tafel slope of 32 m V/dec,when tested in 0.5 M H_(2)SO_(4),better than pure Ir and Pt/C.This work paves the way to the exploration of efficient alloy electrocatalysts for HER.

Expanding the scope of CRISPR/Cas9-mediated genome editing in plants using an xCas9 and Cas9-NG hybrid^FA

The widely used Streptococcus pyogenes Cas9(SpCas9)requires NGG as a protospacer adjacent motif(PAM)for genome editing.Although Sp Cas9 is a powerful genome-editing tool,its use has been limited on the targetable genomic locus lacking NGG PAM.The Sp Cas9 variants xCas9 and Cas9-NG have been developed to recognize NG,GAA,and GAT PAMs in human cel s.Here,we show that xCas9 cannot recognize NG PAMs in tomato,and Cas9-NG can recognize some of our tested NG PAMs in the tomato and Arabidopsis genomes.In addition,we engineered BrSp Cas9(XNG-Cas9)based on mutations from both xCas9 and Cas9-NG,and found that XNG-Cas9 can efficiently mutagenize endogenous target sites with NG,GAG,GAA,and GAT PAMs in the tomato or Arabidopsis genomes.The PAM compatibility of XNG-Cas9 is the broadest reported to date among Cas9 s(SpCas9 and Cas9-NG)active in plant.

Porous Assembly of Metallo-Supramolecule and Polyoxometal-ate via Ionic Complexation with Vapor Sorption Properties

Porous materials have been extensively developed and displayed special applications in diverse fields,however,it still remains a great challenge in developing new synthetic methods with features of energy-saving and easy-operating.In this study,we reported the construction of a series of novel ionic complexes based on discrete supramolecular triangle structure and polyoxometalate[Mo_(6)O_(19)]^(2-),using a quite efficient strategy.The obtained composites exhibit precise 3D network structures with ideal stability con-taining micropores,which were characterized by the 1H NMR,ESI-MS,TEM,SEM,and single-crystal X-ray diffraction.These compo-sites showed differential vapor adsorption behaviors for benzene,toluene,and cyclohexane.This work provides a novel approach for fabricating porous materials through electrostatic interactions and has great potential for gas separation.

Mutational characteristics determined using circulating tumor DNA analysis in triple-negative breast cancer patients with distant metastasis

Dear editor,Breast cancer has been considered as the most common malignancy and the leading cause of death in women worldwide[1].Triple-negative breast cancer(TNBC)accounts for 10%-20%of breast cancers,which are characterized by the absence of estrogen receptor(ER),progesterone receptor(PR),and amplification of human epidermal growth factor receptor 2(HER2)[2].TNBC is well known for its rapid progressiveness,high rate of distant organ recurrence,and poor prognosis.Metastasis remains the major cause of death for patients with TNBCs.Up to date,the only direct treatment for metastatic TNBCs is chemotherapy,which has been challenged by tumor heterogeneity and drug resistance.Lack of effective targeted therapy for metastatic TNBCs impels researchers to focus on discovering potentially actionable targets through mutational profiling.

From Mechanically Interlocked Structures to Host-Guest Chemistry Based on Twisted Dimeric Architectures by Adjusting Space Constraints

Mechanically interlocked molecules(MIMs)and host–guest chemistry have received great attention in the past few decades.However,it remains challenging to design architectures with mechanically interlocked features and construct cavities for guest molecule recognition using similar building blocks.In this study,we designed and constructed a series of novel twisted supramolecular structures by assembling various multitopic terpyridine(tpy)ligands with the same diameter and Zn(II)ions.The obtained complexes exhibited evolutional architectures and showed distinctively different space-constraint effects.Specifically,the assembled dimer SA,SB,and SBH displayed mechanically interlocked phenomena,including[2]catenane and[3]catenane,with an increase in concentration.However,no interlocked structures were observed in complexes SC and SCH constructed by hexatopic tpy ligands due to the significant space constraints.The single-crystal data of complex SCH further proved significant space constraints and illustrated the formation of a relatively closed cavity,which showed excellent host–guest properties for different calixarenes,especially high affinity for calix[6]arene.