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1.
Commun Biol ; 6(1): 27, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631600

RESUMO

The soil-borne fungus Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) causes Fusarium wilt of banana (FWB), which devastates banana production worldwide. Biocontrol is considered to be the most efficient approach to reducing FWB. Here we introduce an approach that spatiotemporally applies Piriformospore indica and Streptomyces morookaensis strains according to their respective strength to increase biocontrol efficacy of FWB. P. indica successfully colonizes banana roots, promotes lateral root formation, inhibits Foc TR4 growth inside the banana plants and reduces FWB. S. morookaensis strain Sm4-1986 secretes different secondary compounds, of which xerucitrinin A (XcA) and 6-pentyl-α-pyrone (6-PP) show the strongest anti-Foc TR4 activity. XcA chelates iron, an essential nutrient in pathogen-plant interaction that determines the output of FWB. 6-PP, a volatile organic compound, inhibits Foc TR4 germination and promotes banana growth. Biocontrol trials in the field demonstrated that application of S. morookaensis lead to improvement of soil properties and increase of rhizosphere-associated microbes that are beneficial to banana growth, which significantly reduces disease incidence of FWB. Our study suggests that optimal utilization of the two biocontrol strains increases efficacy of biocontrol and that regulating iron accessibility in the rhizosphere is a promising strategy to control FWB.


Assuntos
Fusarium , Musa , Fusarium/fisiologia , Rizosfera , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia
2.
Curr Microbiol ; 79(12): 364, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253496

RESUMO

Fusarium wilt caused by Fusarium oxysporum f. sp. niveum is an important manifestation of continuous cropping barrier, which causes the quality and yield of watermelon to decline. In early stage of this study, the organic fertilizer fermented by Bama pig manure applied in soil was proved to significantly inhibit the occurrence of disease by improving the structure of soil microbial community. However, the mechanism was not clear. The high-throughput sequencing technology, combined with network and PICRUSt2 function analysis was used to investigate it. MiSeq sequencing showed that the bacterial community of organic fertilizer treated soil was composed of 34 phyla and 768 genera, the number of genera was higher than that of sterile water treated soil. Fertilization significantly increased the diversity and changed the composition of bacterial community based on alpha, beta diversity, and ANOSIM/Adonis analysis. LEfSe species difference and network analysis showed that fertilization improved the relative abundance of bacteria with biological control or plant growth promotion characteristics in soil, such as Sphingomonas, Halobacillus, Nocardioides, and enhanced the interaction between rhizosphere bacteria, made the network structure more complex. PICRUSt2 also revealed fertilization promoted the bacterial function, such as metabolism and genetic information processing. These results showed that the pig manure organic fertilizer might reduce the occurrence of Fusarium wilt by regulating bacterial community, interaction, and functional metabolism in watermelon rhizosphere soil.


Assuntos
Citrullus , Fusarium , Animais , Bactérias , Citrullus/microbiologia , Fertilizantes , Fusarium/fisiologia , Esterco , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Rizosfera , Solo/química , Microbiologia do Solo , Suínos , Água
3.
Int J Mol Sci ; 23(20)2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36293072

RESUMO

Cotton is an important economic crop. Fusarium and Verticillium are the primary pathogenic fungi that threaten both the quality and sustainable production of cotton. As an opportunistic pathogen, Fusarium causes various human diseases, including fungal keratitis, which is the most common. Therefore, there is an urgent need to study and clarify the resistance mechanisms of cotton and humans toward Fusarium in order to mitigate, or eliminate, its harm. Herein, we first discuss the resistance and susceptibility mechanisms of cotton to Fusarium and Verticillium wilt and classify associated genes based on their functions. We then outline the characteristics and pathogenicity of Fusarium and describe the multiple roles of human neutrophils in limiting hyphal growth. Finally, we comprehensively compare the similarities and differences between animal and plant resistance to Fusarium and put forward new insights into novel strategies for cotton disease resistance breeding and treatment of Fusarium infection in humans.


Assuntos
Fusarium , Verticillium , Humanos , Fusarium/fisiologia , Doenças das Plantas/microbiologia , Melhoramento Vegetal , Resistência à Doença/genética , Gossypium , Mecanismos de Defesa
4.
Plant Physiol ; 190(4): 2847-2867, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-35993881

RESUMO

The roles of mitogen-activated protein kinases (MAPKs) in plant-fungal pathogenic interactions are poorly understood in crops. Here, microscopic, phenotypic, proteomic, and biochemical analyses revealed that roots of independent transcription activator-like effector nuclease (TALEN)-based knockout lines of barley (Hordeum vulgare L.) MAPK 3 (HvMPK3 KO) were resistant against Fusarium graminearum infection. When co-cultured with roots of the HvMPK3 KO lines, F. graminearum hyphae were excluded to the extracellular space, the growth pattern of extracellular hyphae was considerably deregulated, mycelia development was less efficient, and number of appressoria-like structures and their penetration potential were substantially reduced. Intracellular penetration of hyphae was preceded by the massive production of reactive oxygen species (ROS) in attacked cells of the wild-type (WT), but ROS production was mitigated in the HvMPK3 KO lines. Suppression of ROS production in these lines coincided with elevated abundance of catalase (CAT) and ascorbate peroxidase (APX). Moreover, differential proteomic analysis revealed downregulation of several defense-related proteins in WT, and the upregulation of pathogenesis-related protein 1 (PR-1) and cysteine proteases in HvMPK3 KO lines. Proteins involved in suberin formation, such as peroxidases, lipid transfer proteins (LTPs), and the GDSL esterase/lipase (containing "GDSL" aminosequence motif) were differentially regulated in HvMPK3 KO lines after F. graminearum inoculation. Consistent with proteomic analysis, microscopic observations showed enhanced suberin accumulation in roots of HvMPK3 KO lines, most likely contributing to the arrested infection by F. graminearum. These results suggest that TALEN-based knockout of HvMPK3 leads to barley root resistance against Fusarium root rot.


Assuntos
Fusarium , Hordeum , Fusarium/fisiologia , Hordeum/genética , Hordeum/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteômica , Espécies Reativas de Oxigênio/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Nucleases dos Efetores Semelhantes a Ativadores de Transcrição/metabolismo
5.
Microbiol Spectr ; 10(4): e0017122, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35950855

RESUMO

Biofilms are protective structures for pathogens of plants and animals, in which cells are shielded from host defense responses and antimicrobial treatments. Although biofilms are well studied in bacterial pathogens, their development and structure in filamentous fungi, as well as their role in pathogenicity, are poorly understood. We show that the economically important plant pathogen Fusarium graminearum, a filamentous fungus, forms biofilms in vitro, which adhere to polystyrene, a hydrophobic surface. The biofilms have complex hyphal structures surrounded by a polymeric matrix that consists primarily of polysaccharides and extracellular nucleic acids, and lack lipids. Pellicles are formed in liquid cultures, floating biofilm masses that are common in bacterial biofilms, and noted but undescribed in filamentous fungal biofilms. Commonly, F. graminearum grows as hyphal colonies; however, on media which lack electron acceptors, an altered morphology is formed with predominantly short, bulbous hyphae embedded in the matrix. Supplementation of the biofilm-inducing medium with an electron acceptor restores the filamentous hyphal morphology, demonstrating that the formation of bulbous hyphae is due, at least in part, to oxidative stress. Plant hosts infected with pathogens generally respond by producing reactive oxygen species, commonly produced as a defense response. Thus, the formation of biofilms strongly suggests a role in protecting cells from host responses during the course of plant disease. IMPORTANCE Fusarium graminearum is a filamentous fungal pathogen that causes Fusarium head blight (FHB) in cereal crops, leading to devastating crop losses. We have demonstrated the ability of this pathogen to form biofilms. Biofilms are likely to be important in the disease cycle of F. graminearum and other plant pathogens, protecting cells from plant defenses and environmental conditions. Towards this end, we have characterized the formation of biofilms in F. graminearum in vitro, which, together with ongoing characterization of their association with host plants, provides a basis for understanding the functionality of biofilms in the pathogen disease cycle.


Assuntos
Fusarium , Biofilmes , Fusarium/fisiologia , Hifas , Doenças das Plantas/microbiologia
6.
PLoS One ; 17(8): e0272702, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35947630

RESUMO

Watermelon (Citrullus lanatus) is one of the most popular fruit crops. However, Fusarium wilt (FW) is a serious soil-borne disease caused by Fusarium oxysporum f. sp. niveum (FON) that severely limits the development of the watermelon industry. Trichoderma spp. is an important plant anti-pathogen biocontrol agent. The results of our previous study indicated that Trichoderma asperellum M45a (T. asperellum M45a) could control FW by enhancing the relative abundance of plant growth-promoting rhizobacteria (PGPR) in the rhizosphere of watermelon. However, there are few studies on its mechanism in the pathogen resistance of watermelon. Therefore, transcriptome sequencing of T. asperellum M45a-treated watermelon roots combined with metabolome sequencing of the rhizosphere soil was performed with greenhouse pot experiments. The results demonstrated that T. asperellum M45a could stably colonize roots and significantly increase the resistance-related enzymatic activities (e.g., lignin, cinnamic acid, peroxidase and peroxidase) of watermelon. Moreover, the expression of defense-related genes such as MYB and PAL in watermelon roots significantly improved with the inoculation of T. asperellum M45a. In addition, KEGG pathway analysis showed that a large number of differentially expressed genes were significantly enriched in phenylpropane metabolic pathways, which may be related to lignin and cinnamic acid synthesis, thus further inducing the immune response to resist FON. Furthermore, metabolic analysis indicated that four differential metabolic pathways were enriched in M45a-treated soil, including six upregulated compounds and one down-regulated compound. Among them, galactinol and urea were significantly positively correlated with Trichoderma. Hence, this study provides insight into the biocontrol mechanism of T. asperellum M45a to resist soil-borne diseases, which can guide its industrial application.


Assuntos
Citrullus , Fusarium , Trichoderma , Citrullus/genética , Fusarium/fisiologia , Hypocreales , Lignina , Peroxidases , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Solo , Transcriptoma , Trichoderma/genética
7.
Appl Biochem Biotechnol ; 194(12): 5655-5665, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35802242

RESUMO

Fusarium of date palm is a vascular fusariosis caused by a telluric fungus Fusarium oxysporum f.sp. albedinis (F.O.A) which affects the best date varieties in Algeria. Several medicinal plants are adapted with the climatic complexity of the Saharan region, among these plants in the south-west of Algeria Salvia officinalis and Ocimum basilicum. The aim of this work is to study the antifungal effect of flavonoid extracts from Salvia officinalis and Ocimum basilicum leaves by the technique described by Bouchelta et al. (2005), as well the antifungal effect of the aqueous extract of these plants against Fusarium oxysporum f.sp. albedinis isolated from the grove of Igli. The evaluation of the antifungal activity revealed a slight mycelial growth anti-proportional to the concentration of flavonoid extract added to the culture medium with an inhibition index of 73.04% at the concentration 3.17 µg/ml and 57.42% at the concentration 1.13 µg/ml for flavonoids extract of Ocimum basilicum and Salvia officinalis, respectively. In addition, the aqueous extract revealed an inhibition index of 35.15% at the concentration of 0.33 mg/ml and 10.54% at the concentration of 3.92 mg/ml for Salvia officinalis and Ocimum basilicum, respectively.


Assuntos
Fusarium , Ocimum basilicum , Phoeniceae , Plantas Medicinais , Salvia officinalis , Fusarium/fisiologia , Antifúngicos , Flavonoides/farmacologia
9.
Int J Mol Sci ; 23(13)2022 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-35806165

RESUMO

Wall-associated kinases (WAKs) are important receptor-like proteins that play major roles in plant defense against pathogens. Fusarium head blight (FHB), one of the most widespread and devastating crop diseases, reduces wheat yield and leads to quality deterioration. Although WAK gene families have been studied in many plants, systematic research on bread wheat (Triticum aestivum) and its role in FHB resistance, in particular, is lacking. In this study, we identified and characterized 320 genes of the TaWAK family in wheat distributed across all chromosomes except 4B and divided them into three phylogenetic groups. Duplication and synteny analyses provided valuable information on the evolutionary characteristics of the TaWAK genes. The gene expression pattern analysis suggested that TaWAK genes play diverse roles in plant biological processes and that at least 30 genes may be involved in the response to Fusarium infection in wheat spikes, with most of the genes contributing to pectin- and chitin-induced defense pathways. Furthermore, 45 TaWAK genes were identified within 17 hcmQTLs that are related to wheat FHB resistance. Our findings provide potential candidate genes for improving FHB resistance and insights into the future functional analysis of TaWAK genes in wheat.


Assuntos
Fusarium , Pão , Resistência à Doença/genética , Fusarium/fisiologia , Filogenia , Doenças das Plantas/genética , Triticum/genética , Triticum/metabolismo
10.
Theor Appl Genet ; 135(8): 2799-2816, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35781582

RESUMO

KEY MESSAGE: GS and PS performed similarly in improving resistance to FER and FUM content. With cheaper and faster genotyping methods, GS has the potential to be more efficient than PS. Fusarium verticillioides is a common maize (Zea mays L.) pathogen that causes Fusarium ear rot (FER) and produces the mycotoxin fumonisin (FUM). This study empirically compared phenotypic selection (PS) and genomic selection (GS) for improving FER and FUM resistance. Three intermating generations of recurrent GS were conducted in the same time frame and from a common base population as two generations of recurrent PS. Lines sampled from each PS and GS cycle were evaluated in three North Carolina environments in 2020. We observed similar cumulative responses to GS and PS, representing decreases of about 50% of mean FER and FUM compared to the base population. The first cycle of GS was more effective than later cycles. PS and GS both achieved about 70% of predicted total gain from selection for FER, but only about 26% of predicted gains for FUM, suggesting that heritability for FUM was overestimated. We observed a 20% decrease in genetic marker variation from PS and 30% decrease from GS. Our greatest challenge was our inability to quickly obtain dense and consistent set of marker genotypes across generations of GS. Practical implementation of GS in individual small-scale breeding programs will require cheaper and faster genotyping methods, and such technological advances will present opportunities to significantly optimize selection and mating schemes for future GS efforts beyond what we were able to achieve in this study.


Assuntos
Fumonisinas , Fusarium , Fusarium/fisiologia , Genômica/métodos , Melhoramento Vegetal , Doenças das Plantas/genética , Zea mays/genética
11.
J Exp Bot ; 73(18): 6052-6067, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-35709954

RESUMO

Fusarium oxysporum is a soil-borne fungal pathogen of several major food crops. Research on understanding the molecular details of fungal infection and the plant's defense mechanisms against this pathogen has long focused mainly on the tomato-infecting F. oxysporum strains and their specific host plant. However, in recent years, the Arabidopsis thaliana-Fusarium oxysporum strain 5176 (Fo5176) pathosystem has additionally been established to study this plant-pathogen interaction with all the molecular biology, genetic, and genomic tools available for the A. thaliana model system. Work on this system has since produced several new insights, especially with regards to the role of phytohormones involved in the plant's defense response, and the receptor proteins and peptide ligands involved in pathogen detection. Furthermore, work with the pathogenic strain Fo5176 and the related endophytic strain Fo47 has demonstrated the suitability of this system for comparative studies of the plant's specific responses to general microbe- or pathogen-associated molecular patterns. In this review, we highlight the advantages of this specific pathosystem, summarize the advances made in studying the molecular details of this plant-fungus interaction, and point out open questions that remain to be answered.


Assuntos
Arabidopsis , Fusarium , Arabidopsis/genética , Reguladores de Crescimento de Plantas/metabolismo , Padrões Moleculares Associados a Patógenos/metabolismo , Ligantes , Doenças das Plantas/microbiologia , Fusarium/fisiologia , Solo
12.
Plant Sci ; 322: 111361, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35760158

RESUMO

Fusarium head blight (FHB) caused by Fusarium graminearum (Fg) severely affects cereal crops, especially wheat and barley. FHB results in significant yield loss, reduces grain quality and contaminates grains with mycotoxin. The development of FHB-resistant cereal cultivars can be expedited through CRISPR gene editing. The Arabidopsis ethylene insensitive 2 (AtEIN2) plays a key role in ethylene signaling pathway and is critical for monitoring plant growth and defense responses. RNAi down-regulation of the wheat homolog TaEIN2 has been shown to enhance wheat FHB resistance. Here we generated site-specific mutations in AtEIN2 by CRISPR-editing. Detached inflorescence infection assays revealed that AtEIN2 knock-out (KO) mutants displayed enhanced Fg resistance and substantially reduced Fg spore production in planta. Gene expression profiling of defense genes revealed that impairment of AtEIN2 resulted in down-regulation of the ethylene signaling pathway while the salicylic acid signaling pathway was unaffected. Complementation of AtEIN2-KO plants with a barley orthologue, HvEIN2, restored Fg susceptibility, indicating that HvEIN2 is functionally equivalent to its Arabidopsis counterpart and, hence, may have a similar role in conditioning barley Fg susceptibility. These results provide insight into the defense role of EIN2 and a molecular and functional foundation for manipulating HvEIN2 to enhance FHB resistance in barley.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fusarium , Hordeum , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Resistência à Doença/genética , Grão Comestível/metabolismo , Etilenos/metabolismo , Fusarium/fisiologia , Regulação da Expressão Gênica de Plantas , Hordeum/metabolismo , Doenças das Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Receptores de Superfície Celular/metabolismo , Triticum/genética
13.
Plant Genome ; 15(3): e20222, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35633121

RESUMO

Host resistance is an effective and sustainable approach to manage the negative impact of Fusarium head blight (FHB) on wheat (Triticum aestivum L.) grain yield and quality. The objective of this study was to characterize the phenotypic responses and identify quantitative trait loci (QTL) conditioning different FHB resistance types using a panel of 236 elite soft red winter wheat (SRWW) lines in a genome-wide association study (GWAS). The panel was phenotyped for five FHB and three morphological traits under two field and two greenhouse environments in 2018-2019 and 2019-2020. We identified 160 significant marker-trait associations (MTAs) for FHB traits and 11 MTAs for plant height. Eleven QTL showed major effects and explained >10% phenotypic variation (PV) for FHB resistance. Among these major loci, three QTL were stable and five QTL exhibited a pleiotropic effect. The QTL QFhb-3BL, QFhb-5AS, QFhb-5BL, QFhb-7AS.1, QFhb-7AS.2, and QFhb-7BS are presumed to be novel. Pyramiding multiple resistance alleles from all the major-effect QTL resulted in a significant reduction in FHB incidence, severity, index, deoxynivalenol (DON), and Fusarium-damaged kernel (FDK) by 17, 43, 45, 55, and 25%, respectively. Further validation of these QTL could potentially facilitate successful introgression of these resistance loci in new cultivars for improved FHB resistance in breeding programs.


Assuntos
Fusarium , Mapeamento Cromossômico , Fusarium/fisiologia , Estudo de Associação Genômica Ampla , Melhoramento Vegetal , Doenças das Plantas/genética , Triticum/genética
14.
BMC Plant Biol ; 22(1): 257, 2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35606728

RESUMO

BACKGROUND: WRKY transcription factors (TFs) play vital roles in plant growth and development, secondary metabolite synthesis, and response to biotic and abiotic stresses. In a previous transcriptome sequencing analysis of Lilium regale Wilson, we identified multiple WRKY TFs that respond to exogenous methyl jasmonate treatment and lily Fusarium wilt (Fusarium oxysporum). RESULTS: In the present study, the WRKY TF LrWRKY3 was further analyzed to reveal its function in defense response to F. oxysporum. The LrWRKY3 protein was localized in the plant cell nucleus, and LrWRKY3 transgenic tobacco lines showed higher resistance to F. oxysporum compared with wild-type (WT) tobacco. In addition, some genes related to jasmonic acid (JA) biosynthesis, salicylic acid (SA) signal transduction, and disease resistance had higher transcriptional levels in the LrWRKY3 transgenic tobacco lines than in the WT. On the contrary, L. regale scales transiently expressing LrWRKY3 RNA interference fragments showed higher sensitivity to F. oxysporum infection. Moreover, a F. oxysporum-induced defensin gene, Def1, was isolated from L. regale, and the recombinant protein LrDef1 isolated and purified from Escherichia coli possessed antifungal activity to several phytopathogens, including F. oxysporum. Furthermore, co-expression of LrWRKY3 and the LrDef1 promoter in tobacco enhanced the LrDef1 promoter-driven expression activity. CONCLUSIONS: These results clearly indicate that LrWRKY3 is an important positive regulator in response to F. oxysporum infection, and one of its targets is the antimicrobial peptide gene LrDef1.


Assuntos
Fusarium , Lilium , Peptídeos Antimicrobianos , Fusarium/fisiologia , Regulação da Expressão Gênica de Plantas , Lilium/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia
15.
Methods Mol Biol ; 2456: 287-297, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35612750

RESUMO

To distinguish protein abundance changes in biological systems under different conditions, mass spectrometry-based proteomics provides a powerful tool to detect and quantify such responses. Improvements in mass spectrometry instrumentation sensitivity and resolution, along with advanced bioinformatics enable new strategies to study host-pathogen interactions. This protocol uses the state-of-the-art MS-based proteomics to assess infection of the global fungal pathogen Fusarium graminearum, on the world-wide cereal crop Triticum aestivum, resulting in the devastating disease of Fusarium head blight (FHB). Here, host infection is mimicked by inoculating F. graminearum onto T. aestivum cultivars (e.g., FHB-resistant and -susceptible) in the growth room under controlled environment, followed by sample harvesting at different time points (e.g., 24 and 120 h post-inoculation) to assess temporal responses to infection. The collected samples are processed using our in-house pipeline for total protein extraction and quantified via label-free methods by liquid-chromatography-coupled with tandem MS/MS. From this experiment, we define dual perspectives of infection considering dynamic protein abundance changes in both the pathogen and host simultaneously, allowing us to identify strategies used by the pathogen to evade the host defense responses and those used by the host to protect from severe infection.


Assuntos
Fusarium , Fusarium/fisiologia , Doenças das Plantas/microbiologia , Proteômica , Espectrometria de Massas em Tandem , Triticum/microbiologia
16.
Theor Appl Genet ; 135(6): 1985-1996, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35396946

RESUMO

KEY MESSAGE: The effect of the Rht1-genes on FHB resistance depends on anther extrusion and level of background resistance. Qfhs.ifa-5A increases resistance and anther extrusion as efficiently as semi-dwarfing alleles decrease it. The semi-dwarfing reduced height alleles Rht-D1b and Rht-B1b have been deployed in modern wheat cultivars throughout the world, but they increase susceptibility to Fusarium head blight (FHB). Here, we investigated the impact of the Rht1 genes on anther retention (AR) in relation to FHB resistance using four different sets of near-isogenic lines (NILs) with contrasting levels and types of background FHB resistance. NILs were evaluated for FHB severity, plant height and AR in three greenhouse and three field trials using artificial spray inoculation. Rht-B1b and Rht-D1b alleles increased AR and FHB susceptibility in all genetic backgrounds. The magnitude of the effects differed between NIL groups. Increased FHB susceptibility largely followed increased AR. Differences in FHB susceptibility between tall and dwarf haplotypes were largest in the NIL group with the highest changes in AR. In the most resistant NIL group, dwarfed lines had only slightly higher AR than tall lines and maintained good resistance, while both tall and dwarf lines had high levels of retained anthers in the most susceptible NIL group. We further investigated the effect of the major Fusarium resistance QTL Fhb1 and Qfhs.ifa-5A in combination with the Rht1 genes. Qfhs.ifa-5A enhanced anther extrusion in tall as well as semi-dwarf haplotypes, whereas Fhb1 did not affect AR. Qfhs.ifa-5A supported FHB resistance more efficiently than Fhb1 in lines that were more responsive to AR, while both Fhb1 and Qfhs.ifa-5A were equally efficient in NILs that had high background resistance and low response to AR.


Assuntos
Fusarium , Resistência à Doença/genética , Fusarium/fisiologia , Haplótipos , Doenças das Plantas/genética , Locos de Características Quantitativas , Triticum/genética
17.
Microbiol Res ; 260: 127015, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35447486

RESUMO

Chickpea is an important nutritive food crop both for humans and animals. Chickpea wilt caused by Fusarium oxysporum f.sp. ciceris (Foc) results in huge yield losses every year. Chickpea being a food crop requires the development of an eco-friendly bio-pesticide to effectively control the chickpea wilt disease. In this study, more than 50 bacterial stains isolated from the rhizosphere of healthy plants growing in wilt sick soil were examined for their Foc antagonist activities. Out of these, 17 strains showing > 90% growth inhibition of Foc were then characterized for their plant growth-promoting (PGP) and biocontrol traits. The biocontrol and PGP traits identified include amylase, hydrogen cyanide, protease, cellulase, chitinase activities, p-solubilization, nitrogen-fixing, and indole-3-acetic acid production. Two bacterial strains, IR-27 and IR-57, exhibiting the highest Foc proliferation inhibition and the PGP potential along with a consortium of four different strains (Serratia sp. IN-1, Serratia sp. IS-1, Enterobacter sp. IN-2, Enterobacter sp. IN-6) were used for controlling the chickpea wilt disease and growth promotion of the chickpea plants. Confocal laser scanning microscopy revealed their root colonization ability with partial or complete elimination of broken Foc mycelia and hyphae from roots. The bacterial inoculations particularly the consortium significantly suppressed the disease and improved the overall root morphology traits (root length, root surface area, root volume, forks, tips, and crossings), resulting in enhanced growth of the chickpea plants. Significant changes in growth (107% increase in root length, 23% increase in shoot length, and 54% increase in branches) in Foc-challenged plants were observed when inoculated with the consortium. Further investigations revealed that the chickpea plants inoculated with bacterial strains induced the expression of a number of key defence enzymes, including the phenylalanine ammonia lyase, peroxidase, polyphenol peroxidase, ß-1,3 glucanase, which might have helped the plants to thwart the pathogen attack. These findings indicate the potential of our identified bacterial strains to be used as a natural biopesticide for controlling the chickpea wilt disease.


Assuntos
Cicer , Fusarium , Animais , Agentes de Controle Biológico/metabolismo , Cicer/microbiologia , Fusarium/fisiologia , Peroxidases/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Solo
18.
Microbiol Spectr ; 10(2): e0143321, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35254137

RESUMO

Large screens of bacterial strain collections to identify potential biocontrol agents often are time-consuming and costly and fail to provide quantitative results. In this study, we present two quantitative and high-throughput methods to assess the inhibitory capacity of bacterial biocontrol candidates against fungal phytopathogens. One method measures the inhibitory effect of bacterial culture supernatant components on the fungal growth, while the other accounts for direct interaction between growing bacteria and the fungus by cocultivating the two organisms. The antagonistic supernatant method quantifies the culture components' antifungal activity by calculating the cumulative impact of supernatant addition relative to the growth of a nontreated fungal control, while the antagonistic cocultivation method identifies the minimal bacterial cell concentration required to inhibit fungal growth by coinoculating fungal spores with bacterial culture dilution series. Thereby, both methods provide quantitative measures of biocontrol efficiency and allow prominent fungal inhibitors to be distinguished from less effective strains. The combination of the two methods sheds light on the types of inhibition mechanisms and provides the basis for further mode-of-action studies. We demonstrate the efficacy of the methods using Bacillus spp. with different levels of antifungal activities as model antagonists and quantify their inhibitory potencies against classic plant pathogens. IMPORTANCE Fungal phytopathogens are responsible for tremendous agricultural losses on an annual basis. While microbial biocontrol agents represent a promising solution to the problem, there is a growing need for high-throughput methods to evaluate and quantify inhibitory properties of new potential biocontrol agents for agricultural application. In this study, we present two high-throughput and quantitative fungal inhibition methods that are suitable for commercial biocontrol screening.


Assuntos
Antifúngicos , Fusarium , Antifúngicos/farmacologia , Bactérias/metabolismo , Fusarium/fisiologia , Ensaios de Triagem em Larga Escala , Doenças das Plantas/microbiologia
19.
Plant Physiol Biochem ; 179: 144-157, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35344759

RESUMO

Apple replant disease (ARD) is a complex syndrome caused by various biotic and abiotic stresses contained in replanted soil, leading to reduced plant growth and fruit yields and causing serious economic loss. Breeding disease-resistant varieties is an effective and practical method to control ARD. Effective plant defense depends in part on the plant immune responses induced by the recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs). BAK1 participates in the regulation of plant immunity as an important PRR-binding protein. In this study, MdBAK1 overexpression activated indeterminate immune responses in tissue-cultured apple plants. MdBAK1-overexpressing rooted apple plants exhibited enhanced resistance to ARD, as the inhibition of plant growth was significantly alleviated during the replanted soil treatment. In addition, MdBAK1-overexpressing apple plants showed abolished growth inhibition, wilting and root rot induced by Fusarium oxysporum, which is the main pathogen that causes ARD in China. MdBAK1 overexpression changed the microbial community structure in the rhizosphere soil, as reflected by the increase in bacterial content and the decrease in fungal content, and the root exudates of MdBAK1-overexpressing plants inhibited F. oxysporum spore germination compared with that of wild-type plants. Furthermore, the constitutive immunity and cell necrosis induced by the upregulation of MdBAK1 expression were involved in the inhibition of colonization and expansion of F. oxysporum in host plants. In short, MdBAK1 plays an important role in the regulation of apple resistance to ARD, suggesting that MdBAK1 may be a valuable gene for molecular breeding of ARD resistance.


Assuntos
Fusarium , Malus , Fusarium/fisiologia , Malus/metabolismo , Melhoramento Vegetal , Rizosfera
20.
Phytopathology ; 112(9): 1886-1893, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35297645

RESUMO

Bacillus spp. can exert plant growth-promoting effects and biocontrol effects after effective colonization, and bacterial chemotaxis toward plant root exudates is the initial step to colonize. Under biotic stress, plants are able to alter their root exudates to attract or avoid different types of microbes. Hence, Bacillus chemotaxis toward root exudates after pathogen infection is crucial for exerting their beneficial effects. In this study, the Bacillus amyloliquefaciens OR2-30 strain, which exhibited greater chemotaxis ability toward maize root exudates after Fusarium graminearum infection, was screened from 156 rhizosphere microorganisms. The infected maize root exudates were further confirmed to improve the swarming and biofilm formation ability of the OR2-30 strain. Chemotaxis, swarming, and biofilm formation ability were able to influence bacterial colonization. Indeed, the the OR2-30 strain displayed more effective colonization ability in the maize rhizosphere after F. graminearum inoculation. Moreover, lipopeptides produced by OR2-30 were identified as iturins and responsible for suppressing F. graminearum growth. Further study showed that lipopeptides suppressed the growth of F. graminearum by inhibiting conidia formation and germination, inducing reactive oxygen species production and causing cell death in mycelium. Eventually, the OR2-30 strain increased maize resistance against F. graminearum. These results suggested that maize root exudates could recruit B. amyloliquefacines OR2-30 after F. graminearum infection, and that OR2-30 then suppresses the F. graminearum by producing lipopeptides, such as iturins, to protect maize.


Assuntos
Bacillus amyloliquefaciens , Bacillus , Fusarium , Bacillus/fisiologia , Exsudatos e Transudatos/metabolismo , Fusarium/fisiologia , Lipopeptídeos/análise , Lipopeptídeos/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Exsudatos de Plantas/farmacologia , Raízes de Plantas/microbiologia , Zea mays/microbiologia
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