Search Results (12)

HMGR is a crucial enzyme in the biosynthesis of terpenoids. We cloned FaHMGR and found that FaHMGR expression in fruit was significantly higher than other tissues, especially during the coloring stage. Suppression of FaHMGR (FaHMGRR) promoted coloration by increasing anthocyanin content and produced five new components. In contrast, FaHMGR overexpression (FaHMGROE) downregulated most anthocyanin genes and reduced hexanoic acid methyl ester and linalool contents, thereby inhibiting coloring. Transcriptomic and metabolomic analyses showed that DEGs in HMGROE vs. HMGRC (pCAMBIA1302 empty vector transformant serving as a control) were significantly enriched in phenylpropanoid biosynthesis pathway and pathways related to terpenoid metabolism and MeJA, suggesting MeJA as a potential mediator of HMGR’s influence on terpenoid pathways. Additionally, DEGs in HMGRR vs. HMGRC were enriched in anthocyanin biosynthesis, particularly keracyanin and pelargonidin, which may explain the promoted coloration observed in HMGRR. WGCNA analysis identified five module genes with distinct expression patterns in HMGRR and HMGROE, including ERF118 and WRKY12, which may impact fruit quality by regulating HMGR activity. Full article

Malformed coconut fruit occurrence exhibits dual impacts on agricultural productivity and economic returns, primarily through substantial yield reduction and compromised commercial value resulting from morphological defects. To elucidate the molecular determinants underlying this developmental anomaly, we conducted a systematic investigation integrating physiological profiling and transcriptomic sequencing on pulp tissues from malformed (MF) and normal (NF) coconut fruits. Notably, MF specimens displayed marked depletion in carbohydrate reserves, with soluble sugars (SS), reducing sugars (RS), starch (SH), soluble proteins (SP), and fat (FA) declining by 28.57%, 20.43%, 15.51%, 36.78%, and 50.18%, respectively, compared to NF controls. Conversely, a coordinated upregulation of phytohormones was observed, where indole acetic acid (IAA), abscisic acid (ABA), cytokinin (CK), gibberellic acid (GA), brassinosteroid (BR), jasmonic acid (JA), and salicylic acid (SA) levels increased by 31.82–92.97%, while ethylene (ETH) exhibited a paradoxical 30.09% reduction. Transcriptomic dissection revealed 6370 functionally annotated differentially expressed genes (DEGs), comprising 4235 upregulated and 2135 downregulated transcripts. These DEGs were predominantly enriched in critical pathways including plant hormone signal transduction, flavonoid/phenylpropanoid biosynthesis, and carbohydrate metabolic networks. Particularly noteworthy was the enhanced activity of cell wall remodeling enzymes—cellulase (CEL), polygalacturonase (PG), and pectinesterase (PE)—accompanied by differential expression of nine cell wall-associated gene families (CEL, PE, PG, PEL, URG, UTR, VTC2, EXP, XET/XTH) and eight phytohormone-related gene clusters. Functional stratification analysis further identified key transcriptional regulators, with MYB, ERF/AP2, BHLH, WRKY, bZIP, and MADS transcription factors demonstrating significant expression divergence, suggesting their pivotal regulatory roles in MF pathogenesis. This multi-omics integration not only deciphers the molecular choreography of coconut fruit malformation but also establishes a novel conceptual framework for developmental disorder research in perennial crops. Full article

Strawberry (Fragaria ananassa) is a widely grown horticultural crop, which exists in red, yellow, and white varieties. In recent years, the white-fleshed strawberry variety is gaining more attention from consumers for its unique taste and appearance, but a comprehensive understanding of the molecular processes governing the ripening of white-fleshed strawberry remains undisclosed. In this study, based on the joint analysis of physiology, metabolome, and transcriptome, we screened and identified the key metabolites that were highly correlated to the maturation of white-fleshed strawberry (cv. ‘snow white’, SW for short) fruits. In contrast to red-fleshed strawberries, SW fruits exhibited three main ripening stages during the maturation, accompanied by the increases in total soluble solid and total sugar and the declines in total anthocyanin and total acid. Metabolomic analysis identified 832 differential accumulated metabolites (DAMs) at the secondary level of LC-MS/MS, and further investigations suggested that the increase in sucrose, citric acid, and epicatechin levels potentially play a role in the ripening process of SW fruits. Furthermore, abscisic acid and methyl jasmonate were recognized as the primary phytohormones involved in the production of these metabolites. The enrichment analysis of RNA-Seq data revealed that the differential expressed genes (DEGs) were primarily attributed to the pathways of ‘Starch and sucrose metabolism’ and ‘Plant hormone signal transduction’ but were undetected in ‘Flavonoid biosynthesis’ at the late ripening stage. Moreover, the de novo biosynthesis pathway, WGCNA, and Pearson correlation analysis indicated a direct relationship between FaSPS1, FaSPP1, and FaSPP2 with sucrose, FaPEPC1, FaV-PPase2, and FaV-PPase3 with citric acid, and Fa4CL2, Fa4CL3, and FaANR1 with anthocyanin. Further analysis revealed a co-expression of MYBs, bHLHs, NACs, and WRKYs with the structural genes mentioned. Overall, our findings uncovered a molecular mechanism regulating the maturation of white-fleshed strawberry, providing valuable insights for enhancing the flavor of white-fleshed strawberry through the gene-editing technique. Full article

Strawberry is frequently attacked by mites, which directly affects the yield and quality of this fruit species. The WRKY Group III transcription factors (TFs) play an important role in plant tolerance to biotic sources of stress, such as pathogens and insect pests. In this study, six Group III WRKY TFs (FaWRKY25, FaWRKY31, FaWRKY32, FaWRKY43, FaWRKY44, and FaWRKY45) were identified in strawberry. A phylogenetic analysis showed that the six WRKY III TFs were divided into two clades and all had a conserved WRKYGQK domain and the C-X₇-C-X₂₃-H-T-C zinc finger motif. An interaction network analysis revealed that FaWRKY44 was co-expressing with FaWRKY25 and FaWRKY45. The expression patterns showed that the WRKY Group III genes responded to plant hormones and mite infestation in strawberry. To further verify the role of FaWRKY25 in plant resistance to mites, we cloned the FaWRKY25 gene and overexpressed it in transgenic plants. An in vivo subcellular localization analysis indicated that the FaWRKY25 protein was localized in the nucleus. Fewer mites were also detected on the wild-type plants than on FaWRKY25-overexpressing transgenic plants, suggesting that FaWRKY25 negatively regulates the resistance of strawberry to mites. The present study advances our understanding on a potential target that mites use to manipulate host plant defenses. Full article

Strawberry fruit is highly appreciated worldwide for its organoleptic and healthy properties. However, this plant is attacked by many pathogenic fungi, which significantly affect fruit production and quality at pre- and post-harvest stages, making chemical applications the most effective but undesirable strategy to control diseases that has been found so far. Alternatively, genetic manipulation, employing plant key genes involved in defense, such as members of the NPR-like gene family, has been successful in many crops to improve resistance. The identification and use of the endogenous counterpart genes in the plant of interest (as it is the case of strawberry) is desirable as it would increase the favorable outcome and requires prior knowledge of their defense-related function. Using RNAi technology in strawberry, transient silencing of Fragaria ananassa NPR3 members in fruit significantly reduced tissue damage after Colletotrichum acutatum infection, whereas the ectopic expression of either FaNPR3.1 or FaNPR3.2 did not have an apparent effect. Furthermore, the ectopic expression of FaNPR3.2 in Arabidopsis thaliana double-mutant npr3npr4 reverted the disease resistance phenotype to Pseudomonas syringe to wild-type levels. Therefore, the results revealed that members of the strawberry FaNPR3 clade negatively regulate the defense response to pathogens, as do their Arabidopsis AtNPR3/AtNPR4 orthologs. Also, evidence was found showing that FaNPR3 members act in strawberry (F. ananassa) as positive regulators of WRKY genes, FaWRKY19 and FaWRKY24; additionally, in Arabidopsis, FaNPR3.2 negatively regulates its orthologous genes AtNPR3/AtNPR4. We report for the first time the functional characterization of FaNPR3 members in F. ananassa, which provides a relevant molecular basis for the improvement of resistance in this species through new breeding technologies. Full article

WRKY transcription factors are important players in plant regulatory networks, where they control and integrate various physiological processes and responses to biotic and abiotic stresses. Here, we analysed six rose genomes of 5 different species (Rosa chinensis, R. multiflora, R. roxburghii, R. sterilis, and R. rugosa) and extracted a set of 68 putative WRKY genes, extending a previously published set of 58 WRKY sequences based on the R. chinensis genome. Analysis of the promoter regions revealed numerous motifs related to induction by abiotic and, in some cases, biotic stressors. Transcriptomic data from leaves of two rose genotypes inoculated with the hemibiotrophic rose black spot fungus Diplocarpon rosae revealed the upregulation of 18 and downregulation of 9 of these WRKY genes after contact with the fungus. Notably, the resistant genotype exhibited the regulation of 25 of these genes (16 upregulated and 9 downregulated), while the susceptible genotype exhibited the regulation of 20 genes (15 upregulated and 5 downregulated). A detailed RT–qPCR analysis of RcWRKY37, an orthologue of AtWRKY75 and FaWRKY1, revealed induction patterns similar to those of the pathogenesis-related (PR) genes induced in salicylic acid (SA)-dependent defence pathways in black spot inoculation experiments. However, the overexpression of RcWRKY37 in rose petals did not induce the expression of any of the PR genes upon contact with black spot. However, wounding significantly induced the expression of RcWRKY37, while heat, cold, or drought did not have a significant effect. This study provides the first evidence for the role of RcWRKY37 in rose signalling cascades and highlights the differences between RcWRKY37 and AtWRKY75. These results improve our understanding of the regulatory function of WRKY transcription factors in plant responses to stress factors. Additionally, they provide foundational data for further studies. Full article

Zucchini (Cucurbita pepo L.) is one of the main vegetable crops grown under protected cultivation in northern China. Low-temperature (LT) stress severely inhibits the growth of zucchini seedlings, resulting in reductions in yield and quality. Here, using three kinds of different humic acids, including coal-based humic acid (CHA), fulvic acid (FA), and biochemical humic acid (BHA), we investigated the effects of humic acids against LT stress (5 °C) in zucchini seedlings. Treatment with all three kinds of humic acids improves LT stress tolerance by decreasing oxidative damage through increases in antioxidative enzyme activities and the contents of soluble sugar and proline in zucchini seedlings, especially after BHA application. Comparative transcriptomic analysis revealed that a total of 17 differentially expressed genes (DEGs) were commonly induced in the leaves of FA-, CHA-, and BHA-treated zucchini seedlings under LT stress, including calmodulin, ethylene-responsive transcription factors (TFs), peroxidases, and 10 TFs, including two NAC and seven WRKY genes. Altogether, these results indicated that supplementation with humic acids reprograms plant metabolism and modulates the expression of genes involved in ROS scavenging, phytohormone metabolism, or signaling pathways, finally improving LT stress tolerance in zucchini seedlings. Full article

WRKY transcription factors play a nonnegligible role in plant growth and development, but little is known about the involvement of WRKY transcription factors in the regulation of fruit ripening. In this study, FaWRKY71 was identified to be closely related to fruit maturation in octoploid strawberry. FaWRKY71 protein localized in the nucleus and responded to cold, salt, low phosphate, ABA, and light quality in strawberry seedlings. The temporal and spatial pattern expression analysis indicated that FaWRKY71 was expressed in all the detected tissues, especially in the full red fruits. In addition, FaWRKY71 gave rise to the accumulation of anthocyanin content by promoting the expression of structural genes FaF3’H, FaLAR, FaANR, and transport factors FaTT19 and FaTT12 in the flavonoid pathway, and softening the texture of strawberry via up-regulating the abundance of FaPG19 and FaPG21. Furthermore, FaWRKY71 was a positive regulator that mediated resistance against reactive oxygen species by enhancing the enzyme activities of SOD, POD, and CAT, reducing the amount of MDA. Altogether, this study provides new and comprehensive insight into the regulatory mechanisms facilitating fruit ripening in strawberry. Full article

WRKY transcription factors play critical roles in plant growth and development or stress responses. Using up-to-date genomic data, a total of 64 and 257 WRKY genes have been identified in the diploid woodland strawberry, Fragaria vesca, and the more complex allo-octoploid commercial strawberry, Fragaria × ananassa cv. Camarosa, respectively. The completeness of the new genomes and annotations has enabled us to perform a more detailed evolutionary and functional study of the strawberry WRKY family members, particularly in the case of the cultivated hybrid, in which homoeologous and paralogous FaWRKY genes have been characterized. Analysis of the available expression profiles has revealed that many strawberry WRKY genes show preferential or tissue-specific expression. Furthermore, significant differential expression of several FaWRKY genes has been clearly detected in fruit receptacles and achenes during the ripening process and pathogen challenged, supporting a precise functional role of these strawberry genes in such processes. Further, an extensive analysis of predicted development, stress and hormone-responsive cis-acting elements in the strawberry WRKY family is shown. Our results provide a deeper and more comprehensive knowledge of the WRKY gene family in strawberry. Full article

Strawberry is one of the most highly consumed fruits worldwide, but is extremely perishable. This study systematically compared the effects of chitosan, sucrose, glucose, and fructose immersion on the physiology and disease development in harvested strawberries. After storage at 15 °C for 9 days, all sugar treatment groups had significantly higher total soluble solids and total anthocyanin content than those of the control group. All sugar treatment groups inhibited malondialdehyde accumulation. At the end of the storage, chitosan, glucose, and fructose maintained higher superoxide dismutase activity and chitosan maintained higher catalase activity. The chitosan and glucose groups had lowest fruit decay index, followed by sucrose and fructose groups. The fruit firmness and luster were better maintained in the glucose group. Furthermore, genes related to sucrose metabolism (e.g., FaSUS1 and FaSUS2), titratable acidity accumulation (e.g., FaMDH1, FaMDH2, FaCS1, and FaCS2), disease resistance (e.g., FaPGIP1, FaWRKY1, and FaWRKY33) and to anabolic jasmonic acid and abscisic acid pathways (e.g., FaJAZ1, FaJAZ2, FaOPR3, FaNCED1, and FaNCED2) were regulated to varying degrees, suggesting that chitosan and glucose participate in plants’ immune signaling networks and regulate disease resistance in fruit through hormone pathways. The findings provide new insights into the physiological regulation of harvested strawberries. Full article

Fusarium wilt results in undesirable effects on the quality and production of chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How). Fusaric acid (FA), a secondary metabolite of biotin produced by pathogens of genus Fusarium, induced resistant responses in chieh-qua; however, the physiological and molecular mechanism(s) of FA resistance remains largely unknown. In our study, ‘A39’ (FA-resistant cultivar) exhibited decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) enzyme activity when exposed to FA compared with ‘H5’ (FA-susceptible cultivar). More apoptosis cells existed in ‘H5’ than ‘A39’ after 2 days of FA treatment. RNA-seq results revealed that a total of 2968 and 3931 differentially expressed genes (DEGs) were detected under normal conditions (1562 up-regulated and 1406 down-regulated) and FA treatment (2243 up-regulated and 1688 down-regulated), respectively. Interestingly, DEGs associated with pathogen-related protein and ethylene (ET) biosynthesis and signal pathways were most significantly changed during FA stress. Notably, several crucial genes encoding pathogenesis-related protein (CL4451.Contig2, CL2175.Contig4), peroxidase (Unigene49615 and CL11695.Contig2), and ET-responsive transcription factors (TFs) (CL9320.Contig1, CL9849.Contig3, CL6826.Contig2, CL919. Contig6, and CL518.Contig7) were specifically induced after FA treatment. Collectively, the study provides molecular data for isolating candidate genes involved in FA resistance, especially ET related genes in chieh-qua. Full article

WRKY genes and jasmonic acid (JA) play a crucial role in plants’ responses against biotic and abiotic stress. However, the regulating mechanism of WRKY genes on strawberry fruits’ resistance against Botrytis cinerea is largely unknown, and few studies have been performed on their effect on the JA-mediated defense mechanism against B. cinerea. This study explored the effect of FaWRKY25 on the JA-mediated strawberry resistance against B. cinerea. Results showed that the JA content decreased significantly as the fruits matured, whereas the FaWRKY25 expression rose substantially, which led to heightened susceptibility to B. cinerea and in strawberries. External JA treatment significantly increased the JA content in strawberries and reduced the FaWRKY25 expression, thereby enhancing the fruits’ resistance against B. cinerea. FaWRKY25 overexpression significantly lowered the fruits’ resistance against B. cinerea, whereas FaWRKY25 silencing significantly increased resistance. Moreover, FaWRKY25 overexpression significantly lowered the JA content, whereas FaWRKY25 silencing significantly increased it. FaWRKY25 expression level substantially affects the expression levels of genes related to JA biosynthesis and metabolism, other members of the WRKY family, and defense genes. Accordingly, FaWRKY25 plays a crucial role in regulating strawberries’ resistance against B. cinerea and may negatively regulate their JA-mediated resistance mechanism against B. cinerea. Full article