RESUMO
Some tropical sea cucumbers of the family Holothuriidae can efficiently repel or even fatally ensnare predators by sacrificially ejecting a bioadhesive matrix termed the Cuvierian organ (CO), so named by the French zoologist Georges Cuvier who first described it in 1831. Still, the precise mechanisms for how adhesiveness genetically arose in CO and how sea cucumbers perceive and transduce danger signals for CO expulsion during defense have remained unclear. Here, we report the first high-quality, chromosome-level genome assembly of Holothuria leucospilota, an ecologically significant sea cucumber with prototypical CO. The H. leucospilota genome reveals characteristic long-repeat signatures in CO-specific outer-layer proteins, analogous to fibrous proteins of disparate species origins, including spider spidroin and silkworm fibroin. Intriguingly, several CO-specific proteins occur with amyloid-like patterns featuring extensive intramolecular cross-ß structures readily stainable by amyloid indicator dyes. Distinct proteins within the CO connective tissue and outer surface cooperate to give the expelled matrix its apparent tenacity and adhesiveness, respectively. Genomic evidence offers further hints that H. leucospilota directly transduces predator-induced mechanical pressure onto the CO surface through mediation by transient receptor potential channels, which culminates in acetylcholine-triggered CO expulsion in part or in entirety. Evolutionarily, innovative events in two distinct regions of the H. leucospilota genome have apparently spurred CO's differentiation from the respiratory tree to a lethal defensive organ against predators.
Assuntos
Holothuria , Pepinos-do-Mar , Animais , Holothuria/genética , Holothuria/química , Holothuria/metabolismo , Proteínas Amiloidogênicas/metabolismo , AdesividadeRESUMO
Sea cucumbers have an extraordinary regenerative capability. Under stressful conditions, Holothuria glaberrima can eviscerate their internal organs, including the digestive tract. From the mesentery, a rudiment grows and gives rise to a new intestine within a few weeks. In the last decades, the cellular events that occur during intestinal regeneration have been characterized, including apoptosis, cell proliferation, and muscle cell dedifferentiation. Nevertheless, their contribution to the formation and early growth of the rudiment is still unknown. Furthermore, these cellular events' relationship and potential interdependence remain a mystery. Using modulators to inhibit apoptosis and cell proliferation, we tested whether rudiment growth or other regenerative cellular events like muscle cell dedifferentiation were affected. We found that inhibition of apoptosis by zVAD and cell proliferation by aphidicolin and mitomycin did not affect the overall size of the rudiment seven days post-evisceration (7-dpe). Interestingly, animals treated with aphidicolin showed higher levels of muscle cell dedifferentiation in the distal mesentery, which could act as a compensatory mechanism. On the other hand, inhibition of apoptosis led to a decrease in cell proliferation in the rudiment and a delay in the spatiotemporal progression of muscle cell dedifferentiation throughout the rudiment-mesentery structure. Our findings suggest that neither apoptosis nor cell proliferation significantly contributes to early rudiment growth during intestinal regeneration in the sea cucumber. Nevertheless, apoptosis may play an essential role in modulating cell proliferation in the rudiment (a process known as apoptosis-induced proliferation) and the timing for the progression of muscle cell dedifferentiation. These findings provide new insights into the role and relationship of cellular events during intestinal regeneration in an emerging regeneration model.
Assuntos
Pepinos-do-Mar , Animais , Pepinos-do-Mar/fisiologia , Afidicolina , Intestinos , Proliferação de Células , Apoptose , Desdiferenciação CelularRESUMO
Powdery mildew (PM) is one of the most serious fungal diseases affecting cucumbers (Cucumis sativus L.). The mechanism of PM resistance in cucumber is intricate and remains fragmentary as it is controlled by several genes. In this study, we detected the major-effect Quantitative Trait Locus (QTL), PM5.2, involved in PM resistance by QTL mapping. Through fine mapping, the dominant PM resistance gene, CsPM5.2, was cloned and its function was confirmed by transgenic complementation and natural variation identification. In cultivar 9930, a dysfunctional CsPM5.2 mutant resulted from a single nucleotide polymorphism in the coding region and endowed susceptibility to PM. CsPM5.2 encodes a phosphate transporter-like protein PHO1; H3. The expression of CsPM5.2 is ubiquitous and induced by the PM pathogen. In cucumber, both CsPM5.2 and Cspm5.1 (Csmlo1) are required for PM resistance. Transcriptome analysis suggested that the salicylic acid (SA) pathway may play an important role in CsPM5.2-mediated PM resistance. Our findings help parse the mechanisms of PM resistance and provide strategies for breeding PM-resistant cucumber cultivars.
Assuntos
Ascomicetos , Cucumis sativus , Cucumis sativus/genética , Fosfatos , Ascomicetos/genética , Melhoramento Vegetal , Mapeamento Cromossômico , Resistência à Doença/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologiaRESUMO
Cucumber plants are highly susceptible to the hemibiotroph oomycete Phytophthora melonis. However, the mechanism of resistance to cucumber blight remains poorly understood. Here, we demonstrated that cucumber plants with impairment in the biosynthesis of brassinosteroids (BRs) or gibberellins (GAs) were more susceptible to P. melonis. By contrast, increasing levels of endogenous BRs or exogenously application of 24-epibrassinolide enhanced the resistance of cucumber plants against P. melonis. Furthermore, we found that both knockout and overexpression of the BR biosynthesis gene CYP85A1 reduced the endogenous GA3 content compared with that of wild-type plants under the condition of inoculation with P. melonis, and the enhancement of disease resistance conferred by BR was inhibited in plants with silencing of the GA biosynthetic gene GA20ox1 or KAO. Together, these findings suggest that GA homeostasis is an essential factor mediating BRs-induced disease resistance. Moreover, BZR6, a key regulator of BR signaling, was found to physically interact with GA20ox1, thereby suppressing its transcription. Silencing of BZR6 promoted endogenous GA biosynthesis and compromised GA-mediated resistance. These findings reveal multifaceted crosstalk between BR and GA in response to pathogen infection, which can provide a new approach for genetically controlling P. melonis damage in cucumber production.
Assuntos
Brassinosteroides , Cucumis sativus , Resistência à Doença , Giberelinas , Phytophthora , Doenças das Plantas , Phytophthora/fisiologia , Brassinosteroides/metabolismo , Cucumis sativus/microbiologia , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/parasitologia , Resistência à Doença/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/imunologia , Giberelinas/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Transdução de SinaisRESUMO
Skin color is an important trait that determines the cosmetic appearance and quality of fruits. In cucumber, the skin color ranges from white to brown in mature fruits. However, the genetic basis for this important trait remains unclear. We conducted a genome-wide association study of natural cucumber populations, along with map-based cloning techniques, on an F2 population resulting from a cross between Pepino (with yellow-brown fruit skin) and Zaoer-N (with creamy fruit skin). We identified CsMYB60 as a candidate gene responsible for skin coloration in mature cucumber fruits. In cucumber accessions with white to pale yellow skin color, a premature stop mutation (C to T) was found in the second exon region of CsMYB60, whereas light yellow cucumber accessions exhibited splicing premature termination caused by an intronic mutator-like element insertion in CsMYB60. Transgenic CsMYB60c cucumber plants displayed a yellow-brown skin color by promoting accumulation of flavonoids, especially hyperoside, a yellow-colored flavonol. CsMYB60c encodes a nuclear protein that primarily acts as a transcriptional activator through its C-terminal activation motif. RNA sequencing and DNA affinity purification sequencing assays revealed that CsMYB60c promotes skin coloration by directly binding to the YYTACCTAMYT motif in the promoter regions of flavonoid biosynthetic genes, including CsF3'H, which encodes flavonoid 3'-hydroxylase. The findings of our study not only offer insight into the function of CsMYB60 as dominantly controlling fruit coloration, but also highlight that intronic DNA mutations can have a similar phenotypic impact as exonic mutations, which may be valuable in future cucumber breeding programs.
Assuntos
Cucumis sativus , Flavonoides , Frutas , Regulação da Expressão Gênica de Plantas , Pigmentação , Proteínas de Plantas , Fatores de Transcrição , Cucumis sativus/genética , Cucumis sativus/metabolismo , Frutas/genética , Frutas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Flavonoides/metabolismo , Pigmentação/genética , Estudo de Associação Genômica Ampla , Plantas Geneticamente ModificadasRESUMO
The root system is important for the absorption of water and nutrients by plants. Cultivating and selecting a root system architecture (RSA) with good adaptability and ultrahigh productivity have become the primary goals of agricultural improvement. Exploring the correlation between the RSA and crop yield is important for cultivating crop varieties with high-stress resistance and productivity. In this study, 277 cucumber varieties were collected for root system image analysis and yield using germination plates and greenhouse cultivation. Deep learning tools were used to train ResNet50 and U-Net models for image classification and segmentation of seedlings and to perform quality inspection and productivity prediction of cucumber seedling root system images. The results showed that U-Net can automatically extract cucumber root systems with high quality (F1_score ≥ 0.95), and the trained ResNet50 can predict cucumber yield grade through seedling root system image, with the highest F1_score reaching 0.86 using 10-day-old seedlings. The root angle had the strongest correlation with yield, and the shallow- and steep-angle frequencies had significant positive and negative correlations with yield, respectively. RSA and nutrient absorption jointly affected the production capacity of cucumber plants. The germination plate planting method and automated root system segmentation model used in this study are convenient for high-throughput phenotypic (HTP) research on root systems. Moreover, using seedling root system images to predict yield grade provides a new method for rapidly breeding high-yield RSA in crops such as cucumbers.
Assuntos
Cucumis sativus , Aprendizado Profundo , Raízes de Plantas , Plântula , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/fisiologia , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Produtos Agrícolas/crescimento & desenvolvimentoRESUMO
Plants can maintain acquired cold tolerance for a long period after cold priming, even after the resumption of warmer temperatures. However, the transcriptional mechanisms active during the recovery period after cold priming remain unknown. Here, we found that in cucumber (Cucumis sativus), cold priming altered the Histone H3 lysine 4 trimethylation (H3K4me3) signal of sustainably-induced (memory) and non-sustainably-induced (NSI) genes during recovery. In addition, H3K4me3 marks on upregulated memory genes exhibited a specific epigenetic memory during recovery. However, the rank of the H3K4me3 signal on memory and NSI genes in the genome was independent of cold priming, which always contributed to and inhibited the formation of transcription patterns of memory and NIS genes, respectively. Furthermore, the short-lived increase of RESPIRATORY BURST OXIDASE HOMOLOG 5.1 (CsRBOH5.1) expression during recovery after cold priming was essential to maintain high levels of NADPH oxidase activity and apoplastic H2O2, causing cucumber to acquire cold priming and enhancing the maintenance of acquired cold tolerance (MACT). Interestingly, the expression of some key H3K4me3 methyltransferase genes and the accumulation of H3K4me3 on memory genes depended on CsRBOH5.1. Surprisingly, CsRBOH5.1 was essential for almost all genes to form the normal H3K4me3 signaling patterns during recovery, and the necessity was more obvious as recovery progressed. Moreover, transcriptional memory was completely lost in Csrboh5.1 mutants, and the transcriptional patterns of about 80% of NSI genes were disrupted. Overall, our results show that CsRBOH5.1 governs H3K4me3 deposition and cold-induced transcription during recovery after cold priming, affecting the acquisition of cold priming and the intensity of MACT.
RESUMO
Waterlogging is a serious abiotic stress that drastically decreases crop productivity by damaging the root system. Jasmonic acid (JA) inhibits waterlogging-induced adventitious root (AR) formation in cucumber (Cucumis sativus L.). However, we still lack a profound mechanistic understanding of how JA governs AR formation under waterlogging stress. JAZ (JASMONATE ZIM-DOMAIN) proteins are responsible for repressing JA signaling in a transcriptional manner. In this study, we showed that overexpressing CsJAZ8 inhibited the formation of ARs triggered by waterlogging. Molecular analyses revealed that CsJAZ8 inhibited the activation of the R2R3-MYB transcription factor CsMYB6 via direct interaction. Additionally, silencing of CsMYB6 negatively impacted AR formation under waterlogging stress, as CsMYB6 could directly bind to the promoters of 1-aminocyclopropane-1-carboxylate oxidase2 gene CsACO2 and gibberellin 20-oxidases gene CsGA20ox2, facilitating the transcription of these genes. The overexpression of CsACO2 and CsGA20ox2 led to increased levels of ethylene and gibberellin, which facilitated AR formation under waterlogging conditions. On the contrary, silencing these genes resulted in contrasting phenotypes of AR formation. These results highlight that the transcriptional cascade of CsJAZ8 and CsMYB6 plays a critical role in regulating hormonal-mediated cucumber waterlogging-triggered AR formation by inhibiting ethylene and gibberellin accumulation. We anticipate that our findings will provide insights into the molecular mechanisms that drive the emergence of AR in cucumber plants under waterlogging stress.
RESUMO
Fruit neck is the proximal portion of the fruit with undesirable taste that has detrimental effects on fruit shape and commercial value in cucumber. Despite the dramatic variations in fruit neck length of cucumber germplasms, the genes and regulatory mechanisms underlying fruit neck elongation remain mysterious. In this study, we found that Cucumis sativus HECATE1 (CsHEC1) was highly expressed in fruit neck. Knockout of CsHEC1 resulted in shortened fruit neck and decreased auxin accumulation, whereas overexpression of CsHEC1 displayed the opposite effects, suggesting that CsHEC1 positively regulated fruit neck length by modulating local auxin level. Further analysis showed that CsHEC1 directly bound to the promoter of the auxin biosynthesis gene YUCCA4 (CsYUC4) and activated its expression. Enhanced expression of CsYUC4 resulted in elongated fruit neck and elevated auxin content. Moreover, knockout of CsOVATE resulted in longer fruit neck and higher auxin. Genetic and biochemical data showed that CsOVATE physically interacted with CsHEC1 to antagonize its function by attenuating the CsHEC1-mediated CsYUC4 transcriptional activation. In cucumber germplasms, the expression of CsHEC1 and CsYUC4 positively correlated with fruit neck length, while that of CsOVATE showed a negative correlation. Together, our results revealed a CsHEC1-CsOVATE regulatory module that confers fruit neck length variation via CsYUC4-mediated auxin biosynthesis in cucumber.
Assuntos
Cucumis sativus , Cucumis sativus/genética , Frutas/genética , Regulação da Expressão Gênica de Plantas , Ácidos IndolacéticosRESUMO
BACKGROUND: In complex agricultural environments, the presence of shadows, leaf debris, and uneven illumination can hinder the performance of leaf segmentation models for cucumber disease detection. This is further exacerbated by the imbalance in pixel ratios between background and lesion areas, which affects the accuracy of lesion extraction. RESULTS: An original image segmentation framework, the LS-ASPP model, which utilizes a two-stage Atrous Spatial Pyramid Pooling (ASPP) approach combined with adaptive loss to address these challenges has been proposed. The Leaf-ASPP stage employs attention modules and residual structures to capture multi-scale semantic information and enhance edge perception, allowing for precise extraction of leaf contours from complex backgrounds. In the Spot-ASPP stage, we adjust the dilation rate of ASPP and introduce a Convolutional Attention Block Module (CABM) to accurately segment lesion areas. CONCLUSIONS: The LS-ASPP model demonstrates improved performance in semantic segmentation accuracy under complex conditions, providing a robust solution for precise cucumber lesion segmentation. By focusing on challenging pixels and adapting to the specific requirements of agricultural image analysis, our framework has the potential to enhance disease detection accuracy and facilitate timely and effective crop management decisions.
Assuntos
Cucumis sativus , Processamento de Imagem Assistida por Computador , Doenças das Plantas , Processamento de Imagem Assistida por Computador/métodos , Folhas de Planta , AlgoritmosRESUMO
To improve our understanding of the mechanism underlying cucumber glossiness regulation, a novel cucumber mutant with a glossy peel (Csgp) was identified. MutMap, genotyping, and gene editing results demonstrated that CsSEC23, which is the core component of COPII vesicles, mediates the glossiness of cucumber fruit peel. CsSEC23 is functionally conserved and located in the Golgi and endoplasmic reticulum. CsSEC23 could interact with CsSEC31, but this interaction was absent in the Csgp mutant, which decreased the efficiency of COPII vesicle transportation. Genes related to wax and cutin transport were upregulated in the Csgp mutant, and the cuticle structure of the Csgp-mutant peel became thinner. Moreover, the wax and cutin contents were also changed due to CsSEC23 mutation. Taken together, the results obtained from this study revealed that CsSEC23 mediates cucumber glossiness, and this mediating might be affected by COPII vesicle transportation.
RESUMO
The formation of adventitious roots (ARs) derived from hypocotyl is the most important morphological adaptation to waterlogging stress in Cucumis sativus (cucumber). Our previous study showed that cucumbers with the gene CsARN6.1, encoding an AAA ATPase domain-containing protein, were more tolerant to waterlogging through increased AR formation. However, the apparent function of CsARN6.1 remained unknown. Here, we showed that the CsARN6.1 signal was predominantly observed throughout the cambium of hypocotyls, where de novo AR primordia are formed upon waterlogging treatment. The silencing of CsARN6.1 expression by virus-induced gene silencing and CRISPR/Cas9 technologies adversely affects the formation of ARs under conditions of waterlogging. Waterlogging treatment significantly induced ethylene production, thus upregulating CsEIL3 expression, which encodes a putative transcription factor involved in ethylene signaling. Furthermore, yeast one-hybrid, electrophoretic mobility assay and transient expression analyses showed that CsEIL3 binds directly to the CsARN6.1 promoter to initiate its expression. CsARN6.1 was found to interact with CsPrx5, a waterlogging-responsive class-III peroxidase that enhanced H2 O2 production and increased AR formation. These data provide insights into understanding the molecular mechanisms of AAA ATPase domain-containing protein and uncover a molecular mechanism that links ethylene signaling with the formation of ARs triggered by waterlogging.
Assuntos
Cucumis sativus , Cucumis sativus/genética , Cucumis sativus/metabolismo , Etilenos/metabolismo , Hipocótilo/metabolismo , Regulação da Expressão Gênica de Plantas , ATPases Associadas a Diversas Atividades Celulares/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismoRESUMO
The presence or absence of spines is an important economic trait of cucumber fruit. Spines are believed to be a type of specialized trichome on the fruit surface, and all the identified cucumber trichome-less mutants lack fruit spines. However, genes that specifically regulate fruit spine initiation remain to be identified. Here, we found that knocking out cucumber TARGET OF EAT3 homolog (CsTOE3), belonging to the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) family, affected flower development and, more interestingly, inhibited cucumber fruit spine initiation. On analyzing expression patterns by quantitative reverse transcriptase-polymerase chain reaction and in situ hybridization assay, CsTOE3 was found to be highly expressed in male and female flowers, and its mRNA accumulated in the tips of sepal and petal primordia and in the cells of fruit spines and peels. Biochemical analyses indicated that CsTOE3 directly interacts with GLABRA1 (CsGL1) and TRANSPARENT TESTA GLABRA1 (CsTTG1), which are positive regulators of trichome formation. In addition, RNA-seq showed that the transcription levels of eight ERFs were significantly upregulated in CsTOE3 knockout lines. Phytohormone content analysis also revealed a significant increase in the amount of ethylene released by CsTOE3 knockout line, and treatment with the ethylene synthesis inhibitor aminoethoxyvinyl-glycine partly restored the spineless phenotype. Our results suggest that CsTOE3 specifically regulates fruit spine initiation but does not affect the formation of trichomes on other organs in cucumber. Our findings may have a far-reaching significance for cucumber germplasm improvement and quality breeding using fruit spines as the target trait.
Assuntos
Cucumis sativus , Frutas/metabolismo , Proteínas de Plantas/metabolismo , Melhoramento Vegetal , Etilenos/metabolismoRESUMO
BACKGROUND: Hollow heart is a kind of physiological defect that seriously affects the yield, quality, and economic value of cucumber. However, the formation of hollow hearts may relate to multiple factors in cucumber, and it is necessary to conduct analysis. RESULTS: In this study, hollow and non-hollow fruits of cucumber K07 were used for comparative transcriptome sequencing and analysis. 253 differentially expressed genes and 139 transcription factors were identified as being associated with the formation of hollow hearts. Hormone (auxin) signaling and cell wall biosynthesis were mainly enriched in GO and KEGG pathways. Expression levels of key genes involved in indole-3-acetic acid biosynthesis in carpel were lower in the hollow fruits than non-hollow fruits, while there was no difference in the flesh. The concentration of indole-3-acetic also showed lower in the carpel than flesh. The biosynthetic pathway and content analysis of the main components of the cell wall found that lignin biosynthesis had obvious regularity with hollow heart, followed by hemicellulose and cellulose. Correlation analysis showed that there may be an interaction between auxin and cell wall biosynthesis, and they collectively participate in the formation of hollow hearts in cucumber. Among the differentially expressed transcription factors, MYB members were the most abundant, followed by NAC, ERF, and bHLH. CONCLUSIONS: The results and analyses showed that the low content of auxin in the carpel affected the activity of enzymes related to cell wall biosynthesis at the early stage of fruit development, resulting in incomplete development of carpel cells, thus forming a hollow heart in cucumber. Some transcription factors may play regulatory roles in this progress. The results may enrich the theory of the formation of hollow hearts and provide a basis for future research.
Assuntos
Cucumis sativus , Cucumis sativus/genética , Transcriptoma , Ácidos Indolacéticos , Perfilação da Expressão Gênica , Parede Celular , Fatores de Transcrição/genéticaRESUMO
BACKGROUND: The holothurians, commonly known as sea cucumbers, are marine organisms that possess significant dietary, nutritional, and medicinal value. However, the National Center for Biotechnology Information (NCBI) currently possesses only approximately 70 complete mitochondrial genome datasets of Holothurioidea, which poses limitations on conducting comprehensive research on their genetic resources and evolutionary patterns. In this study, a novel species of sea cucumber belonging to the genus Benthodytes, was discovered in the western Pacific Ocean. The genomic DNA of the novel sea cucumber was extracted, sequenced, assembled and subjected to thorough analysis. RESULTS: The mtDNA of Benthodytes sp. Gxx-2023 (GenBank No. OR992091) exhibits a circular structure spanning 17,386 bp, comprising of 13 protein-coding genes (PCGs), 24 non-coding RNAs (2 rRNA genes and 22 tRNA genes), along with two putative control regions measuring 882 bp and 1153 bp, respectively. It exhibits a high AT% content and negative AT-skew, which distinguishing it from the majority of sea cucumbers in terms of environmental adaptability evolution. The mitochondrial gene homology between Gxx-2023 and other sea cucumbers is significantly low, with less than 91% similarity to Benthodytes marianensis, which exhibits the highest level of homology. Additionally, its homology with other sea cucumbers is below 80%. The mitogenome of this species exhibits a unique pattern in terms of start and stop codons, featuring only two types of start codons (ATG and ATT) and three types of stop codons including the incomplete T. Notably, the abundance of AT in the Second position of the codons surpasses that of the First and Third position. The gene arrangement of PCGs exhibits a relatively conserved pattern, while there exists substantial variability in tRNA. Evolutionary analysis revealed that it formed a distinct cluster with B. marianensis and exhibited relatively distant phylogenetic relationships with other sea cucumbers. CONCLUSIONS: These findings contribute to the taxonomic diversity of sea cucumbers in the Elasipodida order, thereby holding significant implications for the conservation of biological genetic resources, evolutionary advancements, and the exploration of novel sea cucumber resources.
Assuntos
Evolução Molecular , Genoma Mitocondrial , Filogenia , Pepinos-do-Mar , Animais , Pepinos-do-Mar/genética , RNA de Transferência/genética , Composição de BasesRESUMO
Drought is the most severe form of stress experienced by plants worldwide. Cucumber is a vegetable crop that requires a large amount of water throughout the growth period. In our previous study, we identified that overexpression of CsHSFA1d could improve cold tolerance and the content of endogenous jasmonic acid in cucumber seedlings. To explore the functional diversities of CsHSFA1d, we treat the transgenic plants under drought conditions. In this study, we found that the heat shock transcription factor HSFA1d (CsHSFA1d) could improve drought stress tolerance in cucumber. CsHSFA1d overexpression increased the expression levels of galactinol synthase (CsGolS3) and raffinose synthase (CsRS) genes, encoding the key enzymes for raffinose family oligosaccharide (RFO) biosynthesis. Furthermore, the lines overexpressing CsHSFA1d showed higher enzymatic activity of GolS and raffinose synthase to increase the content of RFO. Moreover, the CsHSFA1d-overexpression lines showed lower reactive oxygen species (ROS) accumulation and higher ROS-scavenging enzyme activity after drought treatment. The expressions of antioxidant genes CsPOD2, CsAPX1 and CsSOD1 were also upregulated in CsHSFA1d-overexpression lines. The expression levels of stress-responsive genes such as CsRD29A, CsLEA3 and CsP5CS1 were increased in CsHSFA1d-overexpression lines after drought treatment. We conclude that CsHSFA1d directly targets and regulates the expression of CsGolS3 and CsRS to promote the enzymatic activity and accumulation of RFO to increase the tolerance to drought stress. CsHSFA1d also improves ROS-scavenging enzyme activity and gene expression indirectly to reduce drought-induced ROS overaccumulation. This study therefore offers a new gene target to improve drought stress tolerance in cucumber and revealed the underlying mechanism by which CsHSFA1d functions in the drought stress by increasing the content of RFOs and scavenging the excessive accumulation of ROS.
Assuntos
Cucumis sativus , Galactosiltransferases , Regulação da Expressão Gênica de Plantas , Oligossacarídeos , Proteínas de Plantas , Plantas Geneticamente Modificadas , Rafinose , Espécies Reativas de Oxigênio , Cucumis sativus/genética , Cucumis sativus/fisiologia , Cucumis sativus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Rafinose/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Oligossacarídeos/metabolismo , Galactosiltransferases/metabolismo , Galactosiltransferases/genética , Secas , Fatores de Transcrição de Choque Térmico/metabolismo , Fatores de Transcrição de Choque Térmico/genética , Estresse Fisiológico/genéticaRESUMO
BACKGROUND: Three Amino acid Loop Extension (TALE) belongs to the homeobox group of genes that are important constituents of plant systems. The TALE gene family is instrumental not only in growth and development but also plays an essential role in regulating plant response to environmental adversaries. RESULTS: In the present study, we isolated 21 CsTALE genes from the cucumber (Cucumis sativus L.) genome database. Bioinformatics tools were put in place to understand the structural and functional components of the CsTALE gene family. The evolutionary analysis dissected them into seven subclades (KNOX-I, KNOX-II, and BELL-I to BELL-V). The cis-acting elements in the promoter region of CsTALE genes disclosed that they are key regulators of hormonal and stress-related processes. Additionally, the STRING database advocated the concerting role of CsTALE proteins with other key transcription factors potent in plant developmental biology. The CsmiR319 and CsmiR167a-3p targeting the CsTALE15 and CsTALE16, respectively, further assert the importance of the CsTALE gene family posttranscriptional-related processes. Tissue-specific gene expression unfolded the fundamental involvement of CsTALE genes as they were expressed throughout the developmental stages. Under waterlogging stress, the CsTALE17 expressed significantly higher values in WL, WL-NAA, and WL-ETH but not in WL-MeJA-treated samples. CONCLUSIONS: The present study reveals the evolution and functions of the CsTALE gene family in cucumber. Our work will provide a platform that will help future researchers address the issue of waterlogging stress in the Yangtze River Delta.
Assuntos
Cucumis sativus , Regulação da Expressão Gênica de Plantas , Família Multigênica , Reguladores de Crescimento de Plantas , Proteínas de Plantas , Estresse Fisiológico , Cucumis sativus/genética , Cucumis sativus/fisiologia , Estresse Fisiológico/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Evolução Molecular , Filogenia , Genes de PlantasRESUMO
To address salinity stress in plants in an eco-friendly manner, this study investigated the potential effects of salinity-resistant bacteria isolated from saline agricultural soils on the growth of cucumber (Cucumis sativus, cv. Royal) seedlings. A greenhouse factorial experiment was conducted based on a completely randomized design (CRD) with two factors, salinity at four levels and five bacterial treatments, with three replications (n = 3). Initially, fifty bacterial isolates were screened for their salinity and drought tolerance, phosphate solubilization activity, along with production of auxin, siderophore and hydrogen cyanide. Isolates K4, K14, K15, and C8 exhibited the highest resistance to salinity and drought stresses in vitro. Isolates C8 and K15 demonstrated the highest auxin production capacity, generating 2.95 and 2.87 µg mL- 1, respectively, and also exhibited significant siderophore production capacities (by 14% and 11%). Additionally, isolates C8 and K14 displayed greater phosphate solubilization activities, by 184.64 and 122.11 µg mL- 1, respectively. The statistical analysis revealed that the selected four potent isolates significantly enhanced all growth parameters of cucumber plants grown under salinity stress conditions for six weeks. Plant height increased by 41%, fresh and dry weights by 35% and 7%, respectively, and the leaf area index by 85%. The most effective isolate, C8, was identified as Bacillus subtilis based on the 16 S rDNA amplicon sequencing. This study demonstrated that inoculating cucumber seedlings with halotolerant bacterial isolates, such as C8 (Bacillus subtilis), possessing substantial plant growth-promoting properties significantly alleviated salinity stress by enhancing plant growth parameters. These findings suggest a promising eco-friendly strategy for improving crop productivity in saline agricultural environments.
Assuntos
Cucumis sativus , Tolerância ao Sal , Plântula , Cucumis sativus/microbiologia , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/fisiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Plântula/fisiologia , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Bactérias/classificação , Microbiologia do Solo , Fosfatos/metabolismo , Sideróforos/metabolismo , Ácidos Indolacéticos/metabolismo , Salinidade , SecasRESUMO
BACKGROUND: Proteins harboring the SPX domain are crucial for the regulation of phosphate (Pi) homeostasis in plants. This study aimed to identify and analyze the entire SPX gene family within the cucumber genome. RESULTS: The cucumber genome encompassed 16 SPX domain-containing genes, which were distributed across six chromosomes and categorized into four distinct subfamilies: SPX, SPX-MFS, SPX-EXS and SPX-RING, based on their structure characteristics. Additionally, gene duplications and synteny analysis were conducted for CsSPXs, revealing that their promoter regions were enriched with a variety of hormone-responsive, biotic/abiotic stress and typical P1BS-related elements. Tissue expression profiling of CsSPX genes revealed that certain members were specifically expressed in particular organs, suggesting essential roles in cucumber growth and development. Under low Pi stress, CsSPX1 and CsSPX2 exhibited a particularly strong response to Pi starvation. It was observed that the cucumber cultivar Xintaimici displayed greater tolerance to low Pi compared to black-spined cucumber under low Pi stress conditions. Protein interaction networks for the 16 CsSPX proteins were predicted, and yeast two-hybrid assay revealed that CsPHR1 interacted with CsSPX2, CsSPX3, CsSPX4 and CsSPX5, implying their involvement in the Pi signaling pathway in conjunction with CsPHR1. CONCLUSION: This research lays the foundation for further exploration of the function of the CsSPX genes in response to low Pi stress and for elucidating the underlying mechanism.
Assuntos
Cucumis sativus , Família Multigênica , Fósforo , Proteínas de Plantas , Cucumis sativus/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fósforo/metabolismo , Fósforo/deficiência , Genoma de Planta , Genes de Plantas , Regulação da Expressão Gênica de Plantas , FilogeniaRESUMO
BACKGROUND: The goal of this research is to enhance the quality of cucumber seedlings grown in greenhouses by experimenting with various soilless culture mediums (CMs) and the application of pistachio wood vinegar (WV). The experimental setup was designed as a factorial experiment within a randomized complete block design (RCBD), in greenhouse conditions featuring three replications to assess the effects of different culture media (CMs) and concentrations of pistachio wood vinegar (WV) on cucumber seedling growth. Cucumber seeds were planted in three CMs: coco peat-peat moss, coco peat-vermicompost, and date palm compost-vermicompost mixed in a 75:25 volume-to-volume ratio. These were then treated with pistachio WV at concentrations of 0, 0.5, and 1%, applied four times during irrigation following the emergence of the third leaf. RESULTS: The study revealed that treating seedlings with 0.5% WV in the date palm compost-vermicompost CM significantly enhanced various growth parameters. Specifically, it resulted in a 90% increase in shoot fresh mass, a 59% increase in shoot dry mass, an 11% increase in root fresh mass, a 36% increase in root dry mass, a 65% increase in shoot length, a 62% increase in leaf area, a 25% increase in stem diameter, a 41% increase in relative water content (RWC), and a 6% improvement in membrane stability index (MSI), all in comparison to untreated seedlings grown in coco peat-peat moss CM. Furthermore, chlorophyll a, b, total chlorophyll, and carotenoid levels were 2.3, 2.7, 2.6, and 2.7 times higher, respectively, in seedlings treated with 0.5% WV and grown in the date palm compost-vermicompost CM, compared to those treated with the same concentration of WV but grown in coco peat-peat moss CM. Additionally, the Fv/Fm ratio saw a 52% increase. When plant nutrition was enhanced with the date palm compost-vermicompost CM and 1% WV, auxin content rose by 130% compared to seedlings grown in coco peat-peat moss CM and treated with 0.5% WV. CONCLUSIONS: The study demonstrates that using 0.5% WV in conjunction with date palm compost-vermicompost CM significantly betters the quality of cucumber seedlings, outperforming other treatment combinations.