Candidate genes conferring ethylene-response in cultivated peanuts determined by BSA-seq and fine-mapping

Ethylene plays essential roles in plant growth,development and stress responses.The ethylene signaling pathway and molecular mechanism have been studied extensively in Arabidopsis and rice but limited in peanuts.Here,we established a sand-culture method to screen pingyangmycin mutagenized peanut lines based on their specific response to ethylene(“triple response”).An ethylene-insensitive mutant,inhibition of peanut hypocotyl elongation 1(iph1),was identified that showed reduced sensitivity to ethylene in both hypocotyl elongation and root growth.Through bulked segregant analysis sequencing,a major gene related to iph1,named AhIPH1,was preliminarily mapped at the chromosome Arahy.01,and further narrowed to a 450-kb genomic region through substitution mapping strategy.A total of 7014 genes were differentially expressed among the ACC treatment through RNA-seq analysis,of which only the Arahy.5BLU0Q gene in the candidate mapping interval was differentially expressed between WT and mutant iph1.Integrating sequence variations,functional annotation and transcriptome analysis revealed that a predicated gene,Arahy.5BLU0Q,encoding SNF1 protein kinase,may be the candidate gene for AhIPH1.This gene contained two single-nucleotide polymorphisms at promoter region and was more highly expressed in iph1 than WT.Our findings reveal a novel ethylene-responsive gene,which provides a theoretical foundation and new genetic resources for the mechanism of ethylene signaling in peanuts.

Developing Wheat for Improved Yield and Adaptation Under a Changing Climate： Optimization of a Few Key Genes

Wheat grown under rain-fed conditions is often affected by drought worldwide. Future projections from a climate simulation model predict that the combined effects of increasing temperature and changing rainfall patterns will aggravate this drought scenario and may significantly reduce wheat yields unless appropriate varieties are adopted. Wheat is adapted to a wide range of environments due to the diversity in its phenology genes. Wheat phenology offers the opportunity to fight against drought by modifying crop developmental phases according to water availability in target environments. This review summa- rizes recent advances in wheat phenology research, including vernalization （Vrn）, photoperiod （Ppd）, and also dwarfing （Rht） genes. The alleles, haplotypes, and copy number variation identified for Vrn and Ppd genes respond differently in different climatic conditions, and thus could alter not only the development phases but also the yield. Compared with the model plant Arabidopsis, more phenology genes have not yet been identified in wheat; quantifying their effects in target environments would benefit the breeding of wheat for improved drought tolerance. Hence, there is scope to maximize yields in water-limited envi-ronments by deploying appropriate phenology gene combinations along with Rht genes and other important physiological traits that are associated with drought resistance.

Wheat leaf senescence and its regulatory gene network

Wheat leaf senescence is a developmental process that involves expressional changes in thousands of genes that ultimately impact grain protein content(GPC), grain yield(GY), and nitrogen use efficiency.The onset and rate of senescence are strongly influenced by plant hormones and environmental factors e.g. nitrogen availability. At maturity, decrease in nitrogen uptake could enhance N remobilization from leaves and stem to grain, eventually leading to leaf senescence. Early senescence is related to high GPC and somewhat low yield whereas late senescence is often related to high yield and somewhat low GPC. Early or late senescence is principally regulated by up and down-regulation of senescence associated genes. Integration of external and internal factors together with genotypic variation influence senescence associated genes in a developmental age dependent manner. Although regulation of genes involved in senescence has been studied in rice, Arabidopsis, maize, and currently in wheat, there are genotypespecific variations yet to explore. A major effort is needed to understand the interaction of positive and negative senescence regulators in determining the onset of senescence. In wheat, increasing attention has been paid to understand the role of positive senescence regulator, e.g. GPC-1, regulated gene network during early senescence time course. Recently, gene regulatory network involved early to late senescence time course revealed important senescence regulators. However, the known negative senescence regulator Ta NAC-S gene has not been extensively studied in wheat and little is known about its value in breeding. Existing data on senescence-related transcriptome studies and gene regulatory network could effectively be used for functional study in developing nitrogen efficient wheat varieties.

In silico curation of QTL-rich clusters and candidate gene identification for plant height of bread wheat

Many genetic loci for wheat plant height(PH) have been reported, and 26 dwarfing genes have been catalogued. To identify major and stable genetic loci for PH, here we thoroughly summarized these functionally or genetic verified dwarfing loci from QTL linkage analysis and genome-wide association study published from 2003 to 2022. A total of 332 QTL, 270 GWAS loci and 83 genes for PH were integrated onto chromosomes according to their locations in the IWGSC RefSeq v2.1 and 65 QTL-rich clusters(QRC) were defined. Candidate genes in each QRC were predicted based on IWGSC Annotation v2.1 and the information on functional validation of homologous genes in other species. A total of 38 candidate genes were predicted for 65 QRC including three GA2ox genes in QRC-4B-IV, QRC-5A-VIII and QRC-6A-II(Rht24) as well as GA 20-oxidase 2(TaSD1-3A) in QRC-3A-IV. These outcomes lay concrete foundations for mapbased cloning of wheat dwarfing genes and application in breeding.

Advances in the functional study of glutamine synthetase in plant abiotic stress tolerance response

Plant glutamine synthetase(GS,EC6.3.1.2)catalyzes the synthesis of glutamine from glutamate and ammonium ions and acts as a key enzyme in the nitrogen metabolic pathway in organisms.Nitrogen is an essential element for plant growth and development and plays an important role in crop yield and quality formation.Therefore,GS is crucial in many physiological processes in plants.Currently,nitrogen regulation by GS in plants is well-studied in terms of its effect on plant growth and development.This article reviews the regulatory role of plant GS and its molecular mechanism in mitigating stress injury,such as low or high temperature,salinity,drought and oxidation.The function of plant GS in stress tolerance response is focused.The review aims to provide a reference for the utilization of plant GS in crop stress tolerance breeding.

Non-escaping frost tolerant QTL linked genetic loci at reproductive stage in six wheat DH populations

Reproductive stage frost poses a major constraint for wheat production in countries such as Australia.However,little progress has been made in identifying key genes to overcome the constraint.In the present study,a severe frost event hit two large-scale field trials consisting of six doubled haploid(DH)wheat populations at reproductive stage(young microspore stage)in Western Australia,leading to the identification of 30 robust frost QTL on 17 chromosomes.The major 18 QTL with the phenotype variation over 9.5%were located on 13 chromosomes including 2 A,2 B,2 D,3 A,4 A,4 B,4 D,5 A,5 D,6 D,7 A,7 B and7 D.Most frost QTL were closely linked to the QTL of anthesis,maturity,Zadok stages as well as linked to anthesis related genes.Out of those,six QTL were repetitively detected on the homologous regions on 2 B,4 B,4 D,5 A,5 D,7 A in more than two populations.Results showed that the frost damage is associated with alleles of Vrn-A1 a,Vrn-D1 a,Rht-B1 b,Rht-D1 b,and the high copy number of Ppd-B1.However,anthesis QTL and anthesis related genes of Vrn-B1 a and Ta FT3-1 B on chromosomes 5 B and 1 B did not lead to frost damage,indicating that these early-flowering phenotype related genes are compatible with frost tolerance and thus can be utilised in breeding.Our results also indicate that wild-type alleles Rht-B1 a and Rht-D1 a can be used when breeding for frost-tolerant varieties without delaying flowering time.

Wheat genomic study for genetic improvement of traits in China

Bread wheat(Triticum aestivum L.)is a major crop that feeds 40%of the world’s population.Over the past several decades,advances in genomics have led to tremendous achievements in understanding the origin and domestication of wheat,and the genetic basis of agronomically important traits,which promote the breeding of elite varieties.In this review,we focus on progress that has been made in genomic research and genetic improvement of traits such as grain yield,end-use traits,flowering regulation,nutrient use efficiency,and biotic and abiotic stress responses,and various breeding strategies that contributed mainly by Chinese scientists.Functional genomic research in wheat is entering a new era with the availability of multiple reference wheat genome assemblies and the development of cutting-edge technologies such as precise genome editing tools,highthroughput phenotyping platforms,sequencing-based cloning strategies,high-efficiency genetic transformation systems,and speed-breeding facilities.These insights will further extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process,ultimately contributing to more sustainable agriculture in China and throughout the world.

Co/N co-doped graphene-like nanocarbon for highly efficient oxygen reduction electrocatalyst

The development of efficient and inexpensive graphene-based electrocatalysts is of great significance to promote the commercial application of fuel cell and metal-air batteries. In this paper, a new type of Co and N co-doped graphene-like nanocarbon(Co/N-GLC) material was prepared by nano-silicon protection and high temperature pyrolysis.The obtained Co/N-GLC catalyst not only has a similar morphology of graphene, but also possesses a high specific surface area(809 m2 g-1) with hierarchical porous structure(micropores/mesopores), and relative high active dopants content.These properties endow it with a good oxygen reduction activity in alkaline media, which can be comparable to commercial Pt/C catalyst. Moreover, the assembled zinc-air batteries using Co/N-GLC catalyst as the air electrode display a better discharge performance and higher stability compared to that of Pt/C electrode. This work demonstrates that the prepared graphene-like carbon catalyst has a good prospect,which can replace noble metal catalyst at the cathode in metalair batteries.

Wheat gluten protein and its impacts on wheat processing quality

Before the advent of the wheat genomic era, a wide range of studies were conducted to understand the chemistry and functions of the wheat storage proteins,which are the major determinants of wheat flour the suitability of wheat flour for various end products, such as bread, noodles and cakes.Wheat grain protein is divided into gluten and non-gluten fractions and the wheat processing quality mainly depends on the gluten fractions.Gluten provides the unique extensibility and elasticity of dough that are essential for various wheat end products.Disulfide bonds are formed between cysteine residues,which is the chemical bases for the physical properties of dough.Based on the SDS-extractability, grain protein is divided into SDS-unextractable polymeric protein(UPP)and SDS-extractable polymeric protein.The percentage of UPP is positively related to the formation of disulfide bonds in the dough matrix.In the wheat genomic era, new glutenins with long repetitive central domains that contain a high number of consensus hexapeptide and nonapeptide motifs as well as high content of cysteine and glutamine residues should be targeted.