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1.
Theor Appl Genet ; 137(4): 86, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38512498

RESUMO

KEY MESSAGE: Recent developments in understanding the distribution and distinctive features of recombination hotspots are reviewed and approaches are proposed to increase recombination frequency in coldspot regions. Recombination events during meiosis provide the foundation and premise for creating new varieties of crops. The frequency of recombination in different genomic regions differs across eukaryote species, with recombination generally occurring more frequently at the ends of chromosomes. In most crop species, recombination is rare in centromeric regions. If a desired gene variant is linked in repulsion with an undesired variant of a second gene in a region with a low recombination rate, obtaining a recombinant plant combining two favorable alleles will be challenging. Traditional crop breeding involves combining desirable genes from parental plants into offspring. Therefore, understanding the mechanisms of recombination and factors affecting the occurrence of meiotic recombination is important for crop breeding. Here, we review chromosome recombination types, recombination mechanisms, genes and proteins involved in the meiotic recombination process, recombination hotspots and their regulation systems and discuss how to increase recombination frequency in recombination coldspot regions.


Assuntos
Recombinação Homóloga , Melhoramento Vegetal , Genoma , Centrômero , Produtos Agrícolas/genética , Meiose/genética
2.
Theor Appl Genet ; 137(3): 50, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38363421

RESUMO

KEY MESSAGE: Two new major QTL were identified for powdery mildew resistance. We confirmed that the QTL on 7HS contributed mainly to the adult-plant resistance, while another one on chromosome arm 1HS made a significant contribution to the seedling resistance. Powdery mildew (PM), caused by Blumeria hordei, can occur at all post emergent stages of barley and constantly threatens crop production. To identify more genes for effective resistance to powdery mildew for use in breeding programs, 696 barley accessions collected from different regions of the world were evaluated for PM resistance at seedling and adult growth stages in three different states of Australia. These barley accessions were genotyped using DArTSeq with over 18,000 markers for a genome-wide association study (GWAS). Using the FarmCPU model, 54 markers showed significant associations with PM resistance scored at the seedling and adult-plant stages in different states of Australia. Another 40 markers showed tentative associations (LOD > 4.0) with resistance. These markers are distributed across all seven barley chromosomes. Most of them were grouped into eleven QTL regions, coinciding with the locations of most of the reported resistance genes. Two major MTAs were identified on chromosome arms 3HS and 5HL, with one on 3HS contributing to adult plant resistance and the one on 5HL to both seedling and adult plant resistance. An MTA on 7HS contributed mainly to the adult-plant resistance, while another one on chromosome arm 1HS made a significant contribution to the seedling resistance.


Assuntos
Ascomicetos , Hordeum , Hordeum/genética , Estudo de Associação Genômica Ampla , Plântula/genética , Marcadores Genéticos , Ascomicetos/genética , Melhoramento Vegetal , Doenças das Plantas/genética , Resistência à Doença/genética
3.
Theor Appl Genet ; 137(2): 34, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38286831

RESUMO

KEY MESSAGE: Shared changes in transcriptomes caused by Fusarium crown rot infection and drought stress were investigated based on a single pair of near-isogenic lines developed for a major locus conferring tolerance to both stresses. Fusarium crown rot (FCR) is a devastating disease in many areas of cereal production worldwide. It is well-known that drought stress enhances FCR severity but possible molecular relationship between these two stresses remains unclear. To investigate their relationships, we generated several pairs of near isogenic lines (NILs) targeting a locus conferring FCR resistance on chromosome 2D in bread wheat. One pair of these NILs showing significant differences between the two isolines for both FCR resistance and drought tolerance was used to investigate transcriptomic changes in responsive to these two stresses. Our results showed that the two isolines likely deployed different strategies in dealing with the stresses, and significant differences in expressed gene networks exist between the two time points of drought stresses evaluated in this study. Nevertheless, results from analysing Gene Ontology terms and transcription factors revealed that similar regulatory frameworks were activated in coping with these two stresses. Based on the position of the targeted locus, changes in expression following FCR infection and drought stresses, and the presence of non-synonymous variants between the two isolines, several candidate genes conferring resistance or tolerance to these two types of stresses were identified. The NILs generated, the large number of DEGs with single-nucleotide polymorphisms detected between the two isolines, and the candidate genes identified would be invaluable in fine mapping and cloning the gene(s) underlying the targeted locus.


Assuntos
Fusarium , Transcriptoma , Fusarium/fisiologia , Triticum/genética , Secas , Pão , Doenças das Plantas/genética , Perfilação da Expressão Gênica
4.
Phytopathology ; 114(7): 1637-1645, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38451589

RESUMO

Scald is one of the major economically important foliar diseases in barley, causing up to 40% yield loss in susceptible varieties. The identification of quantitative trait loci and elite alleles that confer resistance to scald is imperative in reducing the threats to barley production. In this study, genome-wide association studies were conducted using a panel of 697 barley genotypes to identify quantitative trait loci for scald resistance. Field experiments were conducted over three consecutive years. Among different models used for genome-wide association studies analysis, FarmCPU was shown to be the best-suited model. Nineteen significant marker-trait associations related to scald resistance were identified across six different chromosomes. Eleven of these marker-trait associations correspond to previously reported scald resistance genes Rrs1, Rrs4, and Rrs2, respectively. Eight novel marker-trait associations were identified in this study, with the candidate genes encoding a diverse class of proteins, including region leucine-rich repeats, AP2/ERF transcription factor, homeodomain-leucine zipper, and protein kinase family proteins. The combination of identified superior alleles significantly reduces disease severity scores. The results will be valuable for marker-assisted breeding for developing scald-resistant varieties.


Assuntos
Resistência à Doença , Estudo de Associação Genômica Ampla , Hordeum , Doenças das Plantas , Locos de Características Quantitativas , Hordeum/genética , Hordeum/microbiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Resistência à Doença/genética , Locos de Características Quantitativas/genética , Genótipo , Marcadores Genéticos , Alelos
5.
Biology (Basel) ; 13(6)2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38927301

RESUMO

Biotic stressors pose significant threats to crop yield, jeopardizing food security and resulting in losses of over USD 220 billion per year by the agriculture industry. Plants activate innate defense mechanisms upon pathogen perception and invasion. The plant immune response comprises numerous concerted steps, including the recognition of invading pathogens, signal transduction, and activation of defensive pathways. However, pathogens have evolved various structures to evade plant immunity. Given these facts, genetic improvements to plants are required for sustainable disease management to ensure global food security. Advanced genetic technologies have offered new opportunities to revolutionize and boost plant disease resistance against devastating pathogens. Furthermore, targeting susceptibility (S) genes, such as OsERF922 and BnWRKY70, through CRISPR methodologies offers novel avenues for disrupting the molecular compatibility of pathogens and for introducing durable resistance against them in plants. Here, we provide a critical overview of advances in understanding disease resistance mechanisms. The review also critically examines management strategies under challenging environmental conditions and R-gene-based plant genome-engineering systems intending to enhance plant responses against emerging pathogens. This work underscores the transformative potential of modern genetic engineering practices in revolutionizing plant health and crop disease management while emphasizing the importance of responsible application to ensure sustainable and resilient agricultural systems.

6.
Funct Plant Biol ; 512024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38753957

RESUMO

Detrimental effects of salinity could be mitigated by exogenous zinc (Zn) application; however, the mechanisms underlying this amelioration are poorly understood. This study demonstrated the interaction between Zn and salinity by measuring plant biomass, photosynthetic performance, ion concentrations, ROS accumulation, antioxidant activity and electrophysiological parameters in barley (Hordeum vulgare L.). Salinity stress (200mM NaCl for 3weeks) resulted in a massive reduction in plant biomass; however, both fresh and dry weight of shoots were increased by ~30% with adequate Zn supply. Zinc supplementation also maintained K+ and Na+ homeostasis and prevented H2 O2 toxicity under salinity stress. Furthermore, exposure to 10mM H2 O2 resulted in massive K+ efflux from root epidermal cells in both the elongation and mature root zones, and pre-treating roots with Zn reduced ROS-induced K+ efflux from the roots by 3-4-fold. Similar results were observed for Ca2+ . The observed effects may be causally related to more efficient regulation of cation-permeable non-selective channels involved in the transport and sequestration of Na+ , K+ and Ca2+ in various cellular compartments and tissues. This study provides valuable insights into Zn protective functions in plants and encourages the use of Zn fertilisers in barley crops grown on salt-affected soils.


Assuntos
Homeostase , Hordeum , Raízes de Plantas , Potássio , Salinidade , Zinco , Hordeum/efeitos dos fármacos , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Zinco/farmacologia , Zinco/metabolismo , Homeostase/efeitos dos fármacos , Potássio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sódio/metabolismo , Estresse Salino/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Antioxidantes/farmacologia , Antioxidantes/metabolismo
7.
Plant Physiol Biochem ; 210: 108626, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38615443

RESUMO

Stomatal operation is crucial for optimising plant water and gas exchange and represents a major trait conferring abiotic stress tolerance in plants. About 56% of agricultural land around the globe is classified as acidic, and Al toxicity is a major limiting factor affecting plant performance in such soils. While most of the research work in the field discusses the impact of major abiotic stresses such as drought or salinity on stomatal operation, the impact of toxic metals and, specifically aluminium (Al) on stomatal operation receives much less attention. We aim to fill this knowledge gap by summarizing the current knowledge of the adverse effects of acid soils on plant stomatal development and operation. We summarised the knowledge of stomatal responses to both long-term and transient Al exposure, explored molecular mechanisms underlying plant adaptations to Al toxicity, and elucidated regulatory networks that alleviate Al toxicity. It is shown that Al-induced stomatal closure involves regulations of core stomatal signalling components, such as ROS, NO, and CO2 and key elements of ABA signalling. We also discuss possible targets and pathway to modify stomatal operation in plants grown in acid soils thus reducing the impact of Al toxicity on plant growth and yield.


Assuntos
Alumínio , Estômatos de Plantas , Solo , Alumínio/toxicidade , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Solo/química , Produtos Agrícolas/metabolismo , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Adaptação Fisiológica/efeitos dos fármacos
8.
J Adv Res ; 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38199453

RESUMO

INTRODUCTION: Gibberellin (GA) is a vital phytohormone in regulating plant growth and development. During the "Green Revolution", modification of GA-related genes created semi-dwarfing phenotype in cereal crops but adversely affected grain weight. Gibberellin 2-oxidases (GA2oxs) in barley act as key catabolic enzymes in deactivating GA, but their functions are still less known. OBJECTIVES: This study investigates the physiological function of two HvGA2ox genes in barley and identifies novel semi-dwarf alleles with minimum impacts on other agronomic traits. METHODS: Virus-induced gene silencing and CRISPR/Cas9 technology were used to manipulate gene expression of HvGA2ox9 and HvGA2ox8a in barley and RNA-seq was conducted to compare the transcriptome between wild type and mutants. Also, field trials in multiple environments were performed to detect the functional haplotypes. RESULTS: There were ten GA2oxs that distinctly expressed in shoot, tiller, inflorescence, grain, embryo and root. Knockdown of HvGA2ox9 did not affect plant height, while ga2ox8a mutants generated by CRISPR/Cas9 increased plant height and significantly altered seed width and weight due to the increased bioactive GA4 level. RNA-seq analysis revealed that genes involved in starch and sucrose metabolism were significantly decreased in the inflorescence of ga2ox8a mutants. Furthermore, haplotype analysis revealed one naturally occurring HvGA2ox8a haplotype was associated with decreased plant height, early flowering and wider and heavier seed. CONCLUSION: Our results demonstrate the potential of manipulating GA2ox genes to fine tune GA signalling and biofunctions in desired plant tissues and open a promising avenue for minimising the trade-off effects of Green Revolution semi-dwarfing genes on grain size and weight. The knowledge will promote the development of next generation barley cultivars with better adaptation to a changing climate.

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