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1.
Planta ; 259(4): 86, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453695

RESUMO

MAIN CONCLUSION: MdPRX34L enhanced resistance to Botryosphaeria dothidea by increasing salicylic acid (SA) and abscisic acid (ABA) content as well as the expression of related defense genes. The class III peroxidase (PRX) multigene family is involved in complex biological processes. However, the molecular mechanism of PRXs in the pathogen defense of plants against Botryosphaeria dothidea (B. dothidea) remains unclear. Here, we cloned the PRX gene MdPRX34L, which was identified as a positive regulator of the defense response to B. dothidea, from the apple cultivar 'Royal Gala.' Overexpression of MdPRX34L in apple calli decreased sensitivity to salicylic acid (SA) and abscisic acid(ABA). Subsequently, overexpression of MdPRX34L in apple calli increased resistance to B. dothidea infection. In addition, SA contents and the expression levels of genes related to SA synthesis and signaling in apple calli overexpressing MdPRX34L were higher than those in the control after inoculation, suggesting that MdPRX34L enhances resistance to B. dothidea via the SA pathway. Interestingly, infections in apple calli by B. dothidea caused an increase in endogenous levels of ABA followed by induction of ABA-related genes expression. These findings suggest a potential mechanism by which MdPRX34L enhances plant-pathogen defense against B. dothidea by regulating the SA and ABA pathways.


Assuntos
Ascomicetos , Malus , Malus/metabolismo , Resistência à Doença/genética , Ácido Abscísico/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácido Salicílico/metabolismo , Doenças das Plantas/microbiologia
2.
Commun Biol ; 7(1): 359, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519651

RESUMO

Biocontrol strategies offer a promising alternative to control plant pathogens achieving food safety and security. In this study we apply a RNAseq analysis during interaction between the biocontrol agent (BCA) Papiliotrema terrestris, the pathogen Penicillium expansum, and the host Malus domestica. Analysis of the BCA finds overall 802 upregulated DEGs (differentially expressed genes) when grown in apple tissue, with the majority being involved in nutrients uptake and oxidative stress response. This suggests that these processes are crucial for the BCA to colonize the fruit wounds and outcompete the pathogen. As to P. expansum analysis, 1017 DEGs are upregulated when grown in apple tissue, with the most represented GO categories being transcription, oxidation reduction process, and transmembrane transport. Analysis of the host M. domestica finds a higher number of DEGs in response to the pathogen compared to the BCA, with overexpression of genes involved in host defense signaling pathways in the presence of both of them, and a prevalence of pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) only during interaction with P. expansum. This analysis contributes to advance the knowledge on the molecular mechanisms that underlie biocontrol activity and the tritrophic interaction of the BCA with the pathogen and the host.


Assuntos
Basidiomycota , Malus , Penicillium , Malus/genética , Malus/metabolismo , Malus/microbiologia , Saccharomyces cerevisiae/genética , Perfilação da Expressão Gênica
3.
Physiol Plant ; 176(2): e14238, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38488414

RESUMO

Malus sieversii is a precious apple germplasm resource. Browning of explants is one of the most important factors limiting the survival rate of plant tissue culture. In order to explore the molecular mechanism of the browning degree of different strains of Malus sieversii, we compared the dynamic changes of Malus sieversii and Malus robusta Rehd. during the whole browning process using a multi-group method. A total of 44 048 differentially expressed genes (DEGs) were identified by transcriptome analysis on the DNBSEQ-T7 sequencing platform. KEGG enrichment analysis showed that the DEGs were significantly enriched in the flavonoid biosynthesis pathway. In addition, metabonomic analysis showed that (-)-epicatechin, astragalin, chrysin, irigenin, isoquercitrin, naringenin, neobavaisoflavone and prunin exhibited different degrees of free radical scavenging ability in the tissue culture browning process, and their accumulation in different varieties led to differences in the browning degree among varieties. Comprehensive transcriptome and metabonomics analysis of the data related to flavonoid biosynthesis showed that PAL, 4CL, F3H, CYP73A, CHS, CHI, ANS, DFR and PGT1 were the key genes for flavonoid accumulation during browning. In addition, WGCNA analysis revealed a strong correlation between the known flavonoid structure genes and the selected transcriptional genes. Protein interaction predictions demonstrated that 19 transcription factors (7 MYBs and 12 bHLHs) and 8 flavonoid structural genes had targeted relationships. The results show that the interspecific differential expression of flavonoid genes is the key influencing factor of the difference in browning degree between Malus sieversii and Malus robusta Rehd., providing a theoretical basis for further study on the regulation of flavonoid biosynthesis.


Assuntos
Malus , Malus/genética , Malus/metabolismo , Multiômica , Flavonoides/metabolismo , Perfilação da Expressão Gênica , Transcriptoma , Regulação da Expressão Gênica de Plantas
4.
Proc Natl Acad Sci U S A ; 121(12): e2319582121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38483998

RESUMO

The presence of viruses that spread to both plant and fungal populations in nature has posed intriguingly scientific question. We found a negative-strand RNA virus related to members of the family Phenuiviridae, named Valsa mali negative-strand RNA virus 1 (VmNSRV1), which induced strong hypovirulence and was prevalent in a population of the phytopathogenic fungus of apple Valsa canker (Valsa mali) infecting apple orchards in the Shaanxi Province of China. Intriguingly, VmNSRV1 encodes a protein with a viral cell-to-cell movement function in plant tissue. Mechanical leaf inoculation showed that VmNSRV1 could systemically infect plants. Moreover, VmNSRV1 was detected in 24 out of 139 apple trees tested in orchards in Shaanxi Province. Fungal inoculation experiments showed that VmNSRV1 could be bidirectionally transmitted between apple plants and V. mali, and VmNSRV1 infection in plants reduced the development of fungal lesions on leaves. Additionally, the nucleocapsid protein encoded by VmNSRV1 is associated with and rearranged lipid droplets in both fungal and plant cells. VmNSRV1 represents a virus that has adapted and spread to both plant and fungal hosts and shuttles between these two organisms in nature (phyto-mycovirus) and is potential to be utilized for the biocontrol method against plant fungal diseases. This finding presents further insights into the virus evolution and adaptation encompassing both plant and fungal hosts.


Assuntos
Ascomicetos , Micovírus , Malus , Micoses , Vírus de RNA , Ascomicetos/genética , Vírus de RNA/genética , Doenças das Plantas/microbiologia , Malus/metabolismo
5.
Plant Sci ; 341: 112008, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38307352

RESUMO

miRNAs govern gene expression and regulate plant defense. Alternaria alternata is a destructive fungal pathogen that damages apple. The wild apple germplasm Malus hupehensis is highly resistant to leaf spot disease caused by this fungus. Herein, we elucidated the regulatory and functional role of miR393a in apple resistance against A. alternata by targeting Transport Inhibitor Response 1. Mature miR393 accumulation in infected M. hupehensis increased owing to the transcriptional activation of MIR393a, determined to be a positive regulator of A. alternata resistance to either 'Orin' calli or 'Gala' leaves. 5' RLM-RACE and co-transformation assays showed that the target of miR393a was MhTIR1, a gene encoding a putative F-box auxin receptor that compromised apple immunity. RNA-seq analysis of transgenic calli revealed that MhTIR1 upregulated auxin signaling gene transcript levels and influenced phytohormone pathways and plant-pathogen interactions. miR393a compromised the sensitivity of several auxin-signaling genes to A. alternata infection, whereas MhTIR1 had the opposite effect. Using exogenous indole-3-acetic acid or the auxin synthesis inhibitor L-AOPP, we clarified that auxin enhances apple susceptibility to this pathogen. miR393a promotes SA biosynthesis and impedes pathogen-triggered ROS bursts by repressing TIR1-mediated auxin signaling. We uncovered the mechanism underlying the miR393a-TIR1 module, which interferes with apple defense against A. alternata by modulating the auxin signaling pathway.


Assuntos
Malus , Malus/metabolismo , Alternaria/fisiologia , Ácidos Indolacéticos/metabolismo , Transdução de Sinais , Regulação da Expressão Gênica de Plantas
6.
Sci Rep ; 14(1): 4933, 2024 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-38418625

RESUMO

Red flesh apple (Malus pumila var. medzwetzkyana Dieck), purple leaf plum (Prunus cerasifera Ehrhar f), and purple leaf peach (Prunus persica 'Atropurpurea') are significant ornamental plants within the Rosaceae family. The coloration of their fruits and leaves is crucial in their appearance and nutritional quality. However, qualitative and quantitative studies on flavonoids in the succulent fruits and leaves of multicolored Rosaceae plants are lacking. To unveil the diversity and variety-specificity of flavonoids in these three varieties, we conducted a comparative analysis of flavonoid metabolic components using ultra-high-performance liquid phase mass spectrometry (UPLC-MS/MS). The results revealed the detection of 311 metabolites, including 47 flavonoids, 105 flavonols, 16 chalcones, 37 dihydroflavonoids, 8 dihydroflavonols, 30 anthocyanins, 14 flavonoid carbon glycosides, 23 flavanols, 8 isoflavones, 11 tannins, and 12 proanthocyanidins. Notably, although the purple plum and peach leaves exhibited distinct anthocyanin compounds, paeoniflorin and corythrin glycosides were common but displayed varying glycosylation levels. While the green purple leaf peach fruit (PEF) and red flesh apple leaf (AL) possessed the lowest anthocyanin content, they exhibited the highest total flavonoid content. Conversely, the red flesh apple fruit (AF) displayed the highest anthocyanin content and a diverse range of anthocyanin glycosylation modifications, indicating that anthocyanins predominantly influenced the fruit's color. Purple PLF, PLL, and PEL showcased varying concentrations of anthocyanins, suggesting that their colors result from the co-color interaction between specific types of anthocyanins and secondary metabolites, such as flavonols, flavonoids, and dihydroflavonoids. This study provides novel insights into the variations in tissue metabolites among Rosaceae plants with distinct fruit and leaf colors.


Assuntos
Malus , Prunus persica , Rosaceae , Antocianinas/metabolismo , Frutas/metabolismo , Rosaceae/metabolismo , Cromatografia Líquida , Espectrometria de Massas em Tandem , Folhas de Planta/metabolismo , Flavonoides/metabolismo , Malus/metabolismo , Flavonóis/metabolismo , Prunus persica/metabolismo , Regulação da Expressão Gênica de Plantas
7.
J Nanobiotechnology ; 22(1): 68, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38369472

RESUMO

BACKGROUND: Plant-derived nanovesicles (PDNVs) are a novelty in medical and agrifood environments, with several studies exploring their functions and potential applications. Among fruits, apples (sp. Malus domestica) have great potential as PDNVs source, given their widespread consumption, substantial waste production, and recognized health benefits. Notably, apple-derived nanovesicles (ADNVs) can interact with human cell lines, triggering anti-inflammatory and antioxidant responses. This work is dedicated to the comprehensive biochemical characterization of apple-derived nanovesicles (ADNVs) through proteomic and lipidomic analysis, and small RNAs sequencing. This research also aims to shed light on the underlying mechanism of action (MOA) when ADNVs interface with human cells, through observation of intracellular calcium signalling in human fibroblasts, and to tackles differences in ADNVs content when isolated from fruits derived from integrated and organic production methods cultivars. RESULTS: The ADNVs fraction is mainly composed of exocyst-positive organelles (EXPOs) and MVB-derived exosomes, identified through size and molecular markers (Exo70 and TET-3-like proteins). ADNVs' protein cargo is heterogeneous and exhibits a diverse array of functions, especially in plant's protection (favouring ABA stress-induced signalling, pathogen resistance and Reactive Oxygen Species (ROS) metabolism). Noteworthy plant miRNAs also contribute to phytoprotection. In relation with human cells lines, ADNVs elicit spikes of intracellular Ca2+ levels, utilizing the cation as second messenger, and produce an antioxidant effect. Lastly, organic samples yield a substantial increase in ADNV production and are particularly enriched in bioactive lysophospholipids. CONCLUSIONS: We have conclusively demonstrated that ADNVs confer an antioxidant effect upon human cells, through the initiation of a molecular pathway triggered by Ca2+ signalling. Within ADNVs, a plethora of bioactive proteins, small RNAs, and lipids have been identified, each possessing well-established functions within the realm of plant biology. While ADNVs predominantly function in plants, to safeguard against pathogenic agents and abiotic stressors, it is noteworthy that proteins with antioxidant power might act as antioxidants within human cells.


Assuntos
Antioxidantes , Malus , Humanos , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Cálcio/metabolismo , Verduras , Proteômica , Malus/metabolismo , Transdução de Sinais
8.
Int J Mol Sci ; 25(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339057

RESUMO

The red flesh coloration of apples is a result of a biochemical pathway involved in the biosynthesis of anthocyanins and anthocyanidins. Based on apple genome analysis, a high number of regulatory genes, mainly transcription factors such as MYB, which are components of regulatory complex MYB-bHLH-WD40, and several structural genes (PAL, 4CL, CHS, CHI, F3H, DFR, ANS, UFGT) involved in anthocyanin biosynthesis, have been identified. In this study, we investigated novel genes related to the red-flesh apple phenotype. These genes could be deemed molecular markers for the early selection of new apple cultivars. Based on a comparative transcriptome analysis of apples with different fruit-flesh coloration, we successfully identified and characterized ten potential genes from the plant hormone transduction pathway of auxin (GH3); cytokinins (B-ARR); gibberellins (DELLA); abscisic acid (SnRK2 and ABF); brassinosteroids (BRI1, BZR1 and TCH4); jasmonic acid (MYC2); and salicylic acid (NPR1). An analysis of expression profiles was performed in immature and ripe fruits of red-fleshed cultivars. We have uncovered genes mediating the regulation of abscisic acid, salicylic acid, cytokinin, and jasmonic acid signaling and described their role in anthocyanin biosynthesis, accumulation, and degradation. The presented results underline the relationship between genes from the hormone signal transduction pathway and UFGT genes, which are directly responsible for anthocyanin color transformation as well as anthocyanin accumulation during apple-fruit ripening.


Assuntos
Ciclopentanos , Malus , Oxilipinas , Malus/genética , Malus/metabolismo , Frutas/genética , Frutas/metabolismo , Antocianinas/metabolismo , Perfilação da Expressão Gênica/métodos , Transcriptoma , Ácido Abscísico/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo
9.
Gene ; 904: 148164, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38224923

RESUMO

C2H2-type zinc finger proteins are one of the most widely studied families in plants and play important roles in abiotic stress responses. In the present study, the physicochemical properties, chromosomal locations, evolutionary relationships, and gene structures of 54 C2H2 zinc finger protein (ZFP) family members were analyzed in apple. The MdC2H2-ZFP genes were phylogenetically clustered into seven subfamilies distributed in different densities on 16 chromosomes. The RNA-seq data from various tissues revealed that MdC2H2-ZFPs differentially expressed among root, stem, leaf, flower, and fruits. Quantitative analysis of its expression characteristics showed that the MdC2H2-ZFP genes were rapidly induced as exposure to abiotic stresses such as drought, salt and low temperature etc. Under drought stress, the expression of eight members was significantly up-regulated, and the highest was obtained from MdC2H2-17; as exposure to salt stress, nine MdC2H2-ZFPs was obviously up-regulated, with the highest expression of MdC2H2-13; and under low temperature stress, the expression of seven members was highly up-regulated, and MdC2H2-13 also demonstrated the highest expression which is same as the case under salt stress. Therefore, some members of MdC2H2-ZFP gene family considerably involve in the multiple abiotic stress responses, which may better understand the function of this family and facilitate the breeding of apple for stress tolerance.


Assuntos
Dedos de Zinco CYS2-HIS2 , Malus , Dedos de Zinco CYS2-HIS2/genética , Malus/genética , Malus/metabolismo , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas , Melhoramento Vegetal , Estresse Fisiológico/genética , Filogenia , Dedos de Zinco/genética
10.
Tree Physiol ; 44(2)2024 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-38224320

RESUMO

The level of cadmium (Cd) accumulation in orchard soils is increasing, and excess Cd will cause serious damage to plants. Melatonin is a potent natural antioxidant and has a potential role in alleviating Cd stress. This study aimed to investigate the effects of exogenous melatonin on a root endophyte bacteria community and metabolite composition under Cd stress. The results showed that melatonin significantly scavenged the reactive oxygen species and restored the photosynthetic system (manifested by the improved photosynthetic parameters, total chlorophyll content and the chlorophyll fluorescence parameters (Fv/Fm)), increased the activity of antioxidant enzymes (the activities of catalase, superoxide dismutase, peroxidase and ascorbate oxidase) and reduced the concentration of Cd in the roots and leaves of apple plants. High-throughput sequencing showed that melatonin increased the endophytic bacterial community richness significantly and changed the community structure under Cd stress. The abundance of some potentially beneficial endophytic bacteria (Ohtaekwangia, Streptomyces, Tabrizicola and Azovibrio) increased significantly, indicating that the plants may absorb potentially beneficial microorganisms to resist Cd stress. The metabolomics results showed that melatonin significantly changed the composition of root metabolites, and the relative abundance of some metabolites decreased, suggesting that melatonin may resist Cd stress by depleting root metabolites. In addition, co-occurrence network analysis indicated that some potentially beneficial endophytes may be influenced by specific metabolites. These results provide a theoretical basis for studying the effects of melatonin on the endophytic bacterial community and metabolic composition in apple plants.


Assuntos
Malus , Melatonina , Melatonina/farmacologia , Antioxidantes/metabolismo , Cádmio/toxicidade , Cádmio/metabolismo , Malus/metabolismo , Clorofila/metabolismo
11.
Plant Physiol Biochem ; 207: 108314, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38184884

RESUMO

Calcium is an essential element for plant growth and development, and it plays an important role in the responses of plants to abiotic stress. High concentrations of heavy metal ions in soil significantly affect the yield and quality of crops and pose human health threats when these ions accumulate in edible organs. The Ca2+/H+ exchanger (CAX) family is a class of transporters that mediate the transmembrane transport of both Ca2+ and metal ions, and they are widely involved in regulating plant growth and development and stress responses. Here, we cloned an AtCAX2 ortholog, MdCAX2L-2, from apple. It is constitutively expressed in various apple tissues and significantly induced by Ca2+ and Ba2+ treatments. The MdCAX2L-2 protein is located in the vacuolar membrane in both plant and yeast cells. Overexpression of MdCAX2L-2 enhanced the tolerance of the yeast mutant K667 to high concentrations of Ca2+ and Ba2+. In addition, the role of MdCAX2L-2 in modulating Ba2+ tolerance was identified using MdCAX2L-2-overexpressing transgenic Arabidopsis plants and apple calli. Comparison of growth phenotypes and stress-related physiological indexes under BaCl2 treatment indicated that MdCAX2L-2 could enhance the Ba2+ tolerance of plants by promoting Ba2+ compartmentalization into the vacuoles and eliminating excess ROS. Our results provide insights that will aid future studies examining the function of CAX proteins in regulating stress tolerance in fruit crops, as well as their underlying mechanisms.


Assuntos
Arabidopsis , Malus , Humanos , Malus/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Arabidopsis/metabolismo , Íons/metabolismo , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico
12.
Plant Physiol Biochem ; 207: 108371, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38271863

RESUMO

Apple (Malus domestica) is an economically important rosaceous fruit crop grown at temperate climate zones. Nevertheless, its production is severely affected by scab disease caused by the ascomycetous fungus Venturia inaequalis (VI). Methyl jasmonate (MeJA) is a stress induced plant hormone, shown to induce resistance against wide range of pathogens. The current study investigated the role of MeJA in promoting scab tolerance in susceptible apple varieties through exogenous application of optimized (100 µM) MeJA concentration, followed by VI infection. According to our analysis, applying MeJA exogenously onto leaf surfaces resulted in increased membrane stability and decreased malondialdehyde levels in Red Delicious, suggesting that MeJA is capable of protecting tissues against oxidative damage through its role in restoring membrane stability. In addition, the changes in the levels of key antioxidative enzymes and reactive oxygen species (ROS) showed that exogenous MeJA maintains ROS homeostasis as well. Higher phenylalanine ammonia-lyase activity and increased accumulation of phenylpropanoids in MeJA-treated VI-infected plants indicated the MeJA reprogrammed phenylpropanoid biosynthesis pathway for scab tolerance. Our study of scab tolerance in apples induced by MeJA provides new insights into its physiological and biochemical mechanisms.


Assuntos
Acetatos , Ciclopentanos , Malus , Oxilipinas , Malus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Frutas , Homeostase , Doenças das Plantas/microbiologia
13.
Plant Physiol ; 194(4): 2755-2770, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38235781

RESUMO

Apple Valsa canker (AVC) is a devastating disease of apple (Malus × domestica), caused by Valsa mali (Vm). The Cysteine-rich secretory protein, Antigen 5, and Pathogenesis-related protein 1 (CAP) superfamily protein PATHOGENESIS-RELATED PROTEIN 1-LIKE PROTEIN c (VmPR1c) plays an important role in the pathogenicity of Vm. However, the mechanisms through which it exerts its virulence function in Vm-apple interactions remain unclear. In this study, we identified an apple valine-glutamine (VQ)-motif-containing protein, MdVQ29, as a VmPR1c target protein. MdVQ29-overexpressing transgenic apple plants showed substantially enhanced AVC resistance as compared with the wild type. MdVQ29 interacted with the transcription factor MdWRKY23, which was further shown to bind to the promoter of the jasmonic acid (JA) signaling-related gene CORONATINE INSENSITIVE 1 (MdCOI1) and activate its expression to activate the JA signaling pathway. Disease evaluation in lesion areas on infected leaves showed that MdVQ29 positively modulated apple resistance in a MdWRKY23-dependent manner. Furthermore, MdVQ29 promoted the transcriptional activity of MdWRKY23 toward MdCOI1. In addition, VmPR1c suppressed the MdVQ29-enhanced transcriptional activation activity of MdWRKY23 by promoting the degradation of MdVQ29 and inhibiting MdVQ29 expression and the MdVQ29-MdWRKY23 interaction, thereby interfering with the JA signaling pathway and facilitating Vm infection. Overall, our results demonstrate that VmPR1c targets MdVQ29 to manipulate the JA signaling pathway to regulate immunity. Thus, this study provides an important theoretical basis and guidance for mining and utilizing disease-resistance genetic resources for genetically improving apples.


Assuntos
Ascomicetos , Ciclopentanos , Malus , Oxilipinas , Malus/genética , Malus/metabolismo , Glutamina/metabolismo , Valina/metabolismo , Transdução de Sinais , Doenças das Plantas/genética
14.
J Integr Plant Biol ; 66(2): 265-284, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38284786

RESUMO

Anthocyanins are secondary metabolites induced by environmental stimuli and developmental signals. The positive regulators of anthocyanin biosynthesis have been reported, whereas the anthocyanin repressors have been neglected. Although the signal transduction pathways of gibberellin (GA) and jasmonic acid (JA) and their regulation of anthocyanin biosynthesis have been investigated, the cross-talk between GA and JA and the antagonistic mechanism of regulating anthocyanin biosynthesis remain to be investigated. In this study, we identified the anthocyanin repressor MdbHLH162 in apple and revealed its molecular mechanism of regulating anthocyanin biosynthesis by integrating the GA and JA signals. MdbHLH162 exerted passive repression by interacting with MdbHLH3 and MdbHLH33, which are two recognized positive regulators of anthocyanin biosynthesis. MdbHLH162 negatively regulated anthocyanin biosynthesis by disrupting the formation of the anthocyanin-activated MdMYB1-MdbHLH3/33 complexes and weakening transcriptional activation of the anthocyanin biosynthetic genes MdDFR and MdUF3GT by MdbHLH3 and MdbHLH33. The GA repressor MdRGL2a antagonized MdbHLH162-mediated inhibition of anthocyanins by sequestering MdbHLH162 from the MdbHLH162-MdbHLH3/33 complex. The JA repressors MdJAZ1 and MdJAZ2 interfered with the antagonistic regulation of MdbHLH162 by MdRGL2a by titrating the formation of the MdRGL2a-MdbHLH162 complex. Our findings reveal that MdbHLH162 integrates the GA and JA signals to negatively regulate anthocyanin biosynthesis. This study provides new information for discovering more anthocyanin biosynthesis repressors and explores the cross-talk between hormone signals.


Assuntos
Ciclopentanos , Malus , Oxilipinas , Malus/genética , Malus/metabolismo , Antocianinas/metabolismo , Giberelinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas
15.
J Sci Food Agric ; 104(3): 1621-1629, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37827991

RESUMO

BACKGROUND: Changes in apple fruit quality indices in response to foliar spray with 24-epibrassinolide (EBL) at 0 and 1 µmol L-1 and methyl jasmonate (MeJA) at 0 and 0.5 µmol L-1 , as well as the combination of these phytohormones, were investigated at harvest and during cold storage. RESULTS: Both phytohormones synergistically enhanced the fruit firmness, specific weight, size, fresh weight, water content, total antioxidant activity, total phenolics, ascorbic acid, total anthocyanins, total soluble solids/titratable acidity ratio and precocity. In addition, the fruit abscission pattern was changed in response to different treatments. Treated fruit exhibited lower weight loss and internal breakdown symptoms and higher total soluble solids index, firmness and phytochemicals during cold storage. A negative correlation was seen between fruit mass, firmness, specific weight, antioxidant activity, total phenolics and vitamin C content with internal breakdown occurrence and weight loss. CONCLUSION: Foliar spray with EBL and MeJA during the growth season is a good environmental friendly and safe method for enhancing the apple fruit different quality parameters, marketability and postharvest life. © 2023 Society of Chemical Industry.


Assuntos
Antioxidantes , Malus , Antioxidantes/análise , Malus/metabolismo , Antocianinas/análise , Reguladores de Crescimento de Plantas/metabolismo , Ácido Ascórbico/análise , Frutas/química , Redução de Peso
16.
Plant J ; 117(5): 1413-1431, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38038980

RESUMO

During fruit ripening, polygalacturonases (PGs) are key contributors to the softening process in many species. Apple is a crisp fruit that normally exhibits only minor changes to cell walls and limited fruit softening. Here, we explore the effects of PG overexpression during fruit development using transgenic apple lines overexpressing the ripening-related endo-POLYGALACTURONASE1 gene. MdPG1-overexpressing (PGox) fruit displayed early maturation/ripening with black seeds, conversion of starch to sugars and ethylene production occurring by 80 days after pollination (DAP). PGox fruit exhibited a striking, white-skinned phenotype that was evident from 60 DAP and most likely resulted from increased air spaces and separation of cells in the hypodermis due to degradation of the middle lamellae. Irregularities in the integrity of the epidermis and cuticle were also observed. By 120 DAP, PGox fruit cracked and showed lenticel-associated russeting. Increased cuticular permeability was associated with microcracks in the cuticle around lenticels and was correlated with reduced cortical firmness at all time points and extensive post-harvest water loss from the fruit, resulting in premature shrivelling. Transcriptomic analysis suggested that early maturation was associated with upregulation of genes involved in stress responses, and overexpression of MdPG1 also altered the expression of genes involved in cell wall metabolism (e.g. ß-galactosidase, MD15G1221000) and ethylene biosynthesis (e.g. ACC synthase, MD14G1111500). The results show that upregulation of PG not only has dramatic effects on the structure of the fruit outer cell layers, indirectly affecting water status and turgor, but also has unexpected consequences for fruit development.


Assuntos
Malus , Malus/metabolismo , Frutas/metabolismo , Etilenos/metabolismo , Água/metabolismo , Regulação da Expressão Gênica de Plantas , Parede Celular/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
17.
Int J Biol Macromol ; 257(Pt 1): 128553, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056736

RESUMO

The work was designed to assess the amelioration effect of papain hydrolysis on the biochemical, techno-functional, and biological properties of apple seed protein isolate (API) after 0-90 min of hydrolysis. Hydrolysis significantly enhanced the nutritional value (protein content ˃ 90 %) while decreasing the average particle size. With increasing hydrolysis time, FTIR analysis revealed a transition from α-helix to ß-turn structure, indicating the unfolding of protein structure. This structural alteration positively influenced the functional characteristics, with samples hydrolyzed for 90 min exhibiting excellent solubility, higher water and oil absorption capacity, foaming capacity, and increased emulsifying activity index. Moreover, samples hydrolyzed for 90 min displayed the highest α-glucosidase (29.62-57.43 %), pancreatic lipase inhibition (12.87-31.08 %), and ACE inhibition (25.32-62.70 %) activity. Interestingly, the inhibiting ability of protein hydrolysates against α-glucosidase and ACE was more effective than pancreatic lipase, suggesting their usefulness as a functional ingredient, particularly in type II diabetes and hypertension management.


Assuntos
Diabetes Mellitus Tipo 2 , Malus , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/química , Hidrolisados de Proteína/química , alfa-Glucosidases/metabolismo , Malus/metabolismo , Lipase , Hidrólise , Antioxidantes/química , Angiotensinas , Sementes/metabolismo
18.
Plant J ; 117(4): 1115-1129, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37966861

RESUMO

Nitrogen (N) is an essential nutrient for crop growth and development, significantly influencing both yield and quality. Melatonin (MT), a known enhancer of abiotic stress tolerance, has been extensively studied. However, its relationship with nutrient stress, particularly N deficiency, and the underlying regulatory mechanisms of MT on N absorption remain unclear. In this study, exogenous MT treatment was found to improve the tolerance of apple plants to N deficiency. Apple plants overexpressing the MT biosynthetic gene N-acetylserotonin methyltransferase 9 (MdASMT9) were used to further investigate the effects of endogenous MT on low-N stress. Overexpression of MdASMT9 improved the light harvesting and heat transfer capability of apple plants, thereby mitigating the detrimental effects of N deficiency on the photosynthetic system. Proteomic and physiological data analyses indicated that MdASMT9 overexpression enhanced the trichloroacetic acid cycle and positively modulated amino acid metabolism to counteract N-deficiency stress. Additionally, both exogenous and endogenous MT promoted the transcription of MdHY5, which in turn bound to the MdNRT2.1 and MdNRT2.4 promoters and activated their expression. Notably, MT-mediated promotion of MdNRT2.1 and MdNRT2.4 expression through regulating MdHY5, ultimately enhancing N absorption. Taken together, these findings shed light on the association between MdASMT9-mediated MT biosynthesis and N absorption in apple plants under N-deficiency conditions.


Assuntos
Malus , Melatonina , Melatonina/metabolismo , Malus/genética , Malus/metabolismo , Nitrogênio/metabolismo , Proteômica , Plantas Geneticamente Modificadas/genética
19.
Plant Physiol ; 194(3): 1906-1922, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-37987562

RESUMO

Salinity is a severe abiotic stress that limits plant survival, growth, and development. 14-3-3 proteins are phosphopeptide-binding proteins that are involved in numerous signaling pathways, such as metabolism, development, and stress responses. However, their roles in salt tolerance are unclear in woody plants. Here, we characterized an apple (Malus domestica) 14-3-3 gene, GENERAL REGULATORY FACTOR 8 (MdGRF8), the product of which promotes salinity tolerance. MdGRF8 overexpression improved salt tolerance in apple plants, whereas MdGRF8-RNA interference (RNAi) weakened it. Yeast 2-hybrid, bimolecular fluorescence complementation, pull-down, and coimmunoprecipitation assays revealed that MdGRF8 interacts with the transcription factor MdWRKY18. As with MdGRF8, overexpressing MdWRKY18 enhanced salt tolerance in apple plants, whereas silencing MdWRKY18 had the opposite effect. We also determined that MdWRKY18 binds to the promoters of the salt-related genes SALT OVERLY SENSITIVE 2 (MdSOS2) and MdSOS3. Moreover, we showed that the 14-3-3 protein MdGRF8 binds to the phosphorylated form of MdWRKY18, enhancing its stability and transcriptional activation activity. Our findings reveal a regulatory mechanism by the MdGRF8-MdWRKY18 module for promoting the salinity stress response in apple.


Assuntos
Malus , Tolerância ao Sal , Tolerância ao Sal/genética , Malus/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética
20.
Plant J ; 117(4): 1250-1263, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37991990

RESUMO

High-temperature stress results in protein misfolding/unfolding and subsequently promotes the accumulation of cytotoxic protein aggregates that can compromise cell survival. Heat shock proteins (HSPs) function as molecular chaperones that coordinate the refolding and degradation of aggregated proteins to mitigate the detrimental effects of high temperatures. However, the relationship between HSPs and protein aggregates in apples under high temperatures remains unclear. Here, we show that an apple (Malus domestica) chloroplast-localized, heat-sensitive elongation factor Tu (MdEF-Tu), positively regulates apple thermotolerance when it is overexpressed. Transgenic apple plants exhibited higher photosynthetic capacity and better integrity of chloroplasts during heat stress. Under high temperatures, MdEF-Tu formed insoluble aggregates accompanied by ubiquitination modifications. Furthermore, we identified a chaperone heat shock protein (MdHsp70), as an interacting protein of MdEF-Tu. Moreover, we observed obviously elevated MdHsp70 levels in 35S: MdEF-Tu apple plants that prevented the accumulation of ubiquitinated MdEF-Tu aggregates, which positively contributes to the thermotolerance of the transgenic plants. Overall, our results provide new insights into the molecular chaperone function of MdHsp70, which mediates the homeostasis of thermosensitive proteins under high temperatures.


Assuntos
Malus , Termotolerância , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Fator Tu de Elongação de Peptídeos/genética , Fator Tu de Elongação de Peptídeos/metabolismo , Malus/genética , Malus/metabolismo , Agregados Proteicos , Chaperonas Moleculares/metabolismo , Plantas Geneticamente Modificadas/metabolismo
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