Promoting grain production through high-standard farmland construction:Evidence in China

Food security is a strategic priority for a country’s economic development.In China,high-standard farmland construction(HSFC)is an important initiative to stabilize grain production and increase grain production capacity.Based on panel data from 31 sample provinces,autonomous regions,and municipalities in China from 2005–2017,this study explored the impact of HSFC on grain yield using the difference-in-differences(DID)method.The results showed that HSFC significantly increased total grain production,which is robust to various checks.HSFC increased grain yield through three potential mechanisms.First,it could increase the grain replanting index.Second,it could effectively reduce yield loss due to droughts and floods.Last,HSFC could strengthen the cultivated land by renovating the low-and medium-yielding fields.Heterogeneity analysis found that the HSFC farmland showed a significant increase in grain yield only in the main grain-producing areas and balanced areas.In addition,HSFC significantly increased the yields of rice,wheat,and maize while leading to a reduction in soybean yields.The findings suggest the government should continue to promote HSFC,improve construction standards,and strictly control the“non-agriculturalization”and“non-coordination”of farmland to increase grain production further.At the same time,market mechanisms should be used to incentivize soybean farming,improve returns and stabilize soybean yields.

In situ injectable hydrogel encapsulating Mn/NO-based immune nano-activator for prevention of postoperative tumor recurrence

Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor resection cavity. The MPB-NO@DOX + ATRA gel was fabricated by mixing a thrombin solution, a fibrinogen solution containing all-trans retinoic acid (ATRA), and a Mn/NO-based immune nano-activator termed MPB-NO@DOX. ATRA promoted the differentiation of cancer stem cells, inhibited cancer cell migration, and affected the polarization of tumor-associated macrophages. The outer MnO2 shell disintegrated due to its reaction with glutathione and hydrogen peroxide in the cytoplasm to release Mn2+ and produce O2, resulting in the release of doxorubicin (DOX). The released DOX entered the nucleus and destroyed DNA, and the fragmented DNA cooperated with Mn2+ to activate the cGAS-STING pathway and stimulate an anti-tumor immune response. In addition, when MPB-NO@DOX was exposed to 808 nm laser irradiation, the Fe-NO bond was broken to release NO, which downregulated the expression of PD-L1 on the surface of tumor cells and reversed the immunosuppressive tumor microenvironment. In conclusion, the MPB-NO@DOX + ATRA gel exhibited excellent anti-tumor efficacy. The results of this study demonstrated the great potential of in situ injectable hydrogels in preventing postoperative tumor recurrence.

Successful Treatment of White Lung in Elderly Patients with COVID-19

Novel coronavirus(SARS-CoV-2,hereby known as COVID-19)has the characteristics of rapid variation and multiple variants,which has caused a huge impact on human health worldwide.At the end of 2022,the Omicron variant was widely spread in China,and the patients infected with COVID-19 were mainly concentrated in the elderly over 80 years old and people with serious basic diseases.Pathologically,diffuse lung injury can be seen in the advanced stage of severe and critical diseases,with a large number of inflammatory cells and fibrous mucus exudation,alveolar epithelial cells shedding and necrosis,severe pulmonary edema,hyaline membrane formation,and diffuse ground-glass shadow or consolidation on imaging,which is manifested as“white lung”[1],and its mortality rate has significantly increased.This study reported two cases of elderly patients admitted to the Affiliated Hospital of Hebei University for the treatment of COVID-19.

Defect in Brnym1,a magnesium-dechelatase protein,causes a stay-green phenotype in an EMSmutagenized Chinese cabbage(Brassica campestris L.ssp.pekinensis)line

Leaf color is an important target trait in Chinese cabbage breeding programs.Leaf yellowing may reduce crop commercial and nutritional values.Some plants with the“stay-green”trait maintain leaf greenness during senescence and even after death.Stay-green Chinese cabbage may be a focal point of future breeding projects because it could improve crop quality and yield and prolong shelf life.A new stay-green mutant,non-yellowing mutant 1(nym1),was identified in Chinese cabbage derived from an ethyl methane sulfonate(EMS)-mutagenized population.The mutant had stay-green characteristics and a higher chlorophyll content than the wild-type during leaf senescence.The staygreen trait in the mutant Chinese cabbage was controlled by the recessive gene Brnym1.MutMap and KASP analyses showed that Brnym1(BraA03g050600.3C)encodes an mg-dechelatase(SGR protein),which might be the causal gene of the mutation in Chinese cabbage.A nonsynonymous single nucleotide base substitution(G to A)in the third exon of Brnym1 caused an amino acid substitution from L to F in the highly conserved domain of the magnesiumdechelatase.Ectopic overexpression showed that the BrNYM1 gene of wild-type Chinese cabbage complemented the SGR-defective stay-green mutant nye1-1 of Arabidopsis.The magnesium-dechelatase activity in the nym1 mutant was significantly downregulated compared to that in the wild type.Brnym1 was relatively upregulated in the mutant during late senescence,and BrNYM1 was localized to the chloroplasts.These results indicate that Brnym1(BraA03g050600.3C)is the causal gene of the stay-green mutation and could be of particular significance in the genetic improvement of Chinese cabbage.

表面活性剂类温拌剂对沥青及混合料性能影响分析

依托某高速公路沥青路面中、下面层实体工程,分别以A-70基质沥青和SBS改性A-90沥青为研究对象,对比了添加表面活性剂类温拌剂与未添加表面活性剂类温拌剂的沥青性能以及对应的沥青混合料路用性能指标。结果表明:表面活性剂类温拌剂能够改善沥青内部结构,与原有沥青结构良好配伍,起到部分降粘增韧的作用,添加表面活性剂类温拌剂能够显著提高沥青低温抗裂性能,小幅度提升沥青的抗老化性能;掺加温拌剂的马歇尔试件空隙率更低,较为密实,能够提高沥青混合料的水稳性能、低温性能,对高温稳定性能无明显影响。

The mutation of ent-kaurene synthase,a key enzyme involved in gibberellin biosynthesis,confers a non-heading phenotype to Chinese cabbage(Brassica rapa L.ssp.pekinensis)

The presence of a leafy head is a vital agronomic trait that facilitates the evaluation of the yield and quality of Chinese cabbage.A non-heading mutant(nhm1)was identified in an ethyl methanesulfonate mutagenesis population of the heading Chinese cabbage double haploid line FT.Segregation analysis revealed that a single recessive gene,Brnhm1,controlled the mutant phenotype.Using MutMap,Kompetitive allele-specific PCR,and cloning analyses,we demonstrated that BraA07g042410.3C,which encodes an ent-kaurene synthase involved in the gibberellin biosynthesis pathway,is the nhm1 mutant candidate gene.A single-nucleotide mutation(C to T)in the fourth exon of BraA07g042410.3C caused an amino acid substitution from histidine to tyrosine.Compared to that of the wild-type FT,BraA07g042410.3C in the leaves of the nhm1 mutant had lower levels of expression.In addition,gibberellin contents were lower in the mutant than in the wild type,and the mutant plant phenotype could be restored to that of the wild type after exogenous GA3 treatment.These results indicate that BraA07g042410.3C caused the non-heading mutation.This is the first study to demonstrate a relationship between gibberellin content in the leaves and leafy head formation in Chinese cabbage.These findings facilitate the understanding of the mechanisms underlying leafy head development in Chinese cabbage.

BrDDB1A maintains regular growth of Chinese cabbage via UV tolerance

Normal plant growth and development ensures the timely maturity and expected yield of crops.The repair mechanism of genome damage under adverse circumstances is essential for maintaining regular plant growth.Herein,two allelic growth retardation mutants of Chinese cabbage,grm1 and grm2,were obtained from EMS-mutagenized populations of wild-type'FT'isolated-cultured microspores and seeds,respectively.Both mutants stably inherited and exhibited stunted growth with smaller leafy-heads.Genetic analysis and allelism test manifested that the mutated trait was triggered by a same single recessive nuclear gene.Via BSR-Seq,Brgrm1 was mapped to a target region including 20 genes on chromosome A09.Whole-genome re-sequencing revealed that BraA09g024830.3C in grm1 had a single base(A)deletion in the 17th exon,leading to a termination codon(TAG).Genotyping showed that the mutated phenotype co-segregated with the InDel in recombinants of the closest linkage markers.In addition,cloning of BraA09g024830.3C in grm2 found that a base substitution(G-A)occurred in the last base of the 1st intron causing an additional 263-bp retention in coding sequences,which in turn led to a termination codon(TAA).BraA09g024830.3C(BrDDB1A)is a homolog of Arabidopsis thaliana Damaged DNA Binding Protein 1A(DDB1A),a key gene of UV tolerance involved in DNA damage repair.The two mutants exhibited normal plant growth identical with wild-type under an extremely low UV radiation.Our results demonstrated that BrDDB1A contributes to maintaining regular plant growth in Chinese cabbage,which provide insights into elucidating the molecular mechanism underlying Chinese cabbage growth and development.

Fine mapping of Brebm6,a gene conferring the early-bolting phenotype in Chinese cabbage(Brassica rapa ssp.pekinensis)

In flowering plants,bolting signals the transition from vegetative to reproductive growth,and it is consequently an important agronomic trait for the stalk-use Chinese cabbage Baicaitai.There is an urgent need to create germplasm resources for Chinese cabbage that have easy bolting characteristics.In this investigation,early bolting mutant 6(ebm6)was created by treating Chinese cabbage double haploid(DH)'FT'seeds with an ethyl methanesulfonate(EMS)solution.Phenotypic analysis showed that the mutant ebm6 flowered remarkably earlier than the wild-type'FT'.Genetic analysis indicated that this early bolting trait was controlled by a recessive nuclear gene.In mutant ebm6,the causal gene BraA02g003340.3C(BrFLC2)was predicted using MutMap and Kompetitive Allele Specific PCR genotyping(KASP),as the gene encodes a MADSbox transcription factor.The 3259-bp BrFLC2 gene possessed seven exons and six introns,and in the first exon,a single nucleotide C-to-T substitution in the highly conserved MADS-box domain resulted in the premature termination of translation of the BrFLC2 protein sequence.This research supported a critical role of BrFLC2 in controlling flowering time in B.rapa.The early flowering ebm6 mutant could also be a useful material in Baicaitai breeding.

Autotriploid origin of Carassius auratus as revealed by chromosomal locus analysis

In the Dongting water system, the Carassius auratus(Crucian carp) complex is characterized by the coexistence of diploid forms(2n=100, 2n CC) and polyploid forms. Chromosomal and karyotypic analyses have suggested that the polyploid C. auratus has a triploid(3n=150, 3n CC) and a tetraploid origin(4n=200), respectively. However, there is a lack of direct genetic evidence to support this conclusion. In this paper, analysis of the 5S r DNA chromosomal locus revealed that the 3n CC is of triploid origin. Analysis of the species-specific chromosomal centromere locus revealed that 3n CC individuals possess three sets of C. auratus-derived chromosomes. Our results provide direct cytogenetic evidence suggesting that individuals with 150 chromosomes are of autotriploid origin within the C. auratus complex. It marks an important contribution to the study of polyploidization and the evolution of vertebrates.