Methylisothiazolinone pollution inhibited root stem cells and regeneration through auxin transport modification in Arabidopsis thaliana.

Methylisothiazolinone (MIT) is a widely used preservative and biocide to prevent product degradation, yet its potential impact on plant growth remains poorly understood. In this study, we investigated MIT's toxic effects on Arabidopsis thaliana root growth. Exposure to MIT significantly inhibited Arabidopsis root growth, associated with reduced root meristem size and root meristem cell numbers. We explored the polar auxin transport pathway and stem cell regulation as key factors in root meristem function. Our findings demonstrated that MIT suppressed the expression of the auxin efflux carrier PIN1 and major root stem cell regulators (PLT1, PLT2, SHR, and SCR). Additionally, MIT hindered root regeneration by downregulating the quiescent center (QC) marker WOX5. Transcriptome analysis revealed MIT-induced alterations in gene expression related to oxidative stress, with physiological experiments confirming elevated reactive oxygen species (ROS) levels and increased cell death in root tips at concentrations exceeding 50 µM. In summary, this study provides critical insights into MIT's toxicity on plant root development and regeneration, primarily linked to modifications in polar auxin transport and downregulation of genes associated with root stem cell regulation.

Systematic identification and functional analysis of root meristem growth factors (RGFs) reveals role of PgRGF1 in modulation of root development and ginsenoside production in Panax ginseng.

Panax ginseng C.A. Mey., known for its medicinal and dietary supplement properties, primarily contains pharmacologically active ginsenosides. However, the regulatory mechanisms linking ginseng root development with ginsenoside biosynthesis are still unclear. Root meristem growth factors (RGFs) are crucial for regulating plant root growth. In our study, we identified five ginseng RGF peptide sequences from the ginseng genome and transcriptome libraries. We treated Arabidopsis and ginseng adventitious roots with exogenous Panax ginseng RGFs (PgRGFs) to assess their activities. Our results demonstrate that PgRGF1 influences gravitropic responses and reduces lateral root formation in Arabidopsis. PgRGF1 has been found to restrict the number and length of ginseng adventitious root branches in ginseng. Given the medicinal properties of ginseng, We determined the ginsenoside content and performed transcriptomic analysis of PgRGF1-treated ginseng adventitious roots. Specifically, the total ginsenoside content in ginseng adventitious roots decreased by 19.98 % and 63.71 % following treatments with 1 µM and 10 µM PgRGF1, respectively, compared to the control. The results revealed that PgRGF1 affects the accumulation of ginsenosides by regulating the expression of genes associated with auxin transportation and ginsenoside biosynthesis. These findings suggest that PgRGF1, as a peptide hormone regulator in ginseng, can modulate adventitious root growth and ginsenoside accumulation.

Molecular network mechanism in cerebral ischemia-reperfusion rats treated with human urine stem cells.

Objective: To explore the effect of human urine-derived stem cells (husc) in improving the neurological function of rats with cerebral ischemia-reperfusion (CIR), and report new molecular network by bioinformatics, combined with experiment validation. Methods: After CIR model was established, and husc were transplanted into the lateral ventricle of rats，neurological severe score (NSS) andgene network analysis were performed. Firstly, we input the keywords "Cerebral reperfusion" and "human urine stem cells" into Genecard database and merged data with findings from PubMed so as to get their targets genes, and downloaded them to make Venny intersection plot. Then, Gene ontology (GO) analysis, kyoto encyclopedia of genes and genomes (KEGG) pathway analysis and protein-protein interaction (PPI) were performed to construct molecular network of core genes. Lastly, the expressional level of core genes was validated via quantitative real-time polymerase chain reaction (qRT-PCR), and localized by immunofluorescence. Results: Compared with the Sham group, the neurological function of CIR rats was significantly improved after the injection of husc into the lateral ventricle; at 14 days, P = 0.028, which was statistically significant. There were 258 overlapping genes between CIR and husc, and integrated with 252 genes screened from PubMed and CNKI. GO enrichment analysis were mainly involved neutrophil degranulation, neutrophil activation in immune response and platelet positive regulation of degranulation, Hemostasis, blood coagulation, coagulation, etc. KEGG pathway analysis was mainly involved in complement and coagulation cascades, ECM-receptor. Hub genes screened by Cytoscape consist ofCD44, ACTB, FN1, ITGB1, PLG, CASP3, ALB, HSP90AA1, EGF, GAPDH. Lastly, qRT-PCR results showed statistic significance (P < 0.05) in ALB, CD44 and EGF before and after treatment, and EGF immunostaining was localized in neuron of cortex. Conclusion: husc transplantation showed a positive effect in improving neural function of CIR rats, and underlying mechanism is involved in CD44, ALB, and EGF network.

The interaction between PDCD4 and YB1 is critical for cervical cancer stemness and cisplatin resistance.

Cancer multidrug resistance (MDR) is existence in stem cell-like cancer cells characterized by stemness including high-proliferation and self-renewal. Programmed cell death 4 (PDCD4), as a proapoptotic gene, whether it engaged in cancer stemness and cisplatin resistance is still unknown. Here we showed that PDCD4 expressions in Hela/DDP (cisplatin resistance) cells were lower than in parental Hela cells. Moreover, the levels of drug resistance genes and typical stemness markers were markedly elevated in Hela/DDP cells. In vivo, xenograft tumor assay confirmed that knockdown of PDCD4 accelerated the grafted tumor growth. In vitro, colony formation and MTT assay demonstrated that PDCD4 overexpression inhibited cells proliferation in conditions with or without cisplatin. By contrast, PDCD4 deficiency provoked cell proliferation and cisplatin resistance. On mechanism, PDCD4 decreased the protein levels of pAKT and pYB1, accompanied by reduced MDR1 expression. Correspondingly, luciferase reporter assay showed PDCD4 regulated MDR1 promoter activity entirely relied on YB1. Furthermore, Ch-IP, GST-pulldown, and Co-IP assays provided novel evidence that PDCD4 could directly bind with YB1 by the nucleolar localization signal (NOLS) segment, causing the reduced YB1 binding into the MDR1 promoter region through blocking YB1 nucleus translocation, triggering the decreased MDR1 transcription. Taken together, PDCD4-pAKT-pYB1 forms the integrated molecular network to regulate MDR1 transcription during the process of stemness-associated cisplatin resistance.

Genome-wide identification of cotton GRAM family proteins reveals that GRAM31 regulates fiber length.

The glucosyltransferases, Rab-like GTPase activators and myotubularins (GRAM) domain is highly conserved in eukaryotic cells and is found in proteins involved in membrane-associated processes. GRAM domain proteins have not yet been functionally characterized in cotton. In this study, we identified 164 genes encoding GRAM domain proteins in four cotton species, comprising two subfamilies. In Gossypium hirsutum, our transcriptome data showed that GhGRAM31 was predominantly expressed during the rapid elongation stage of fiber development and that it might control fiber length. GhGRAM31-RNAi transgenic cotton lines showed inhibition of fiber elongation and produced shorter mature fibers, and this was coupled with expression changes of genes related to fiber development. In addition, lint percentage and seed size were also decreased in the RNAi lines. Further examination revealed that GhGRAM31 directly interacts with two other GRAM-domain proteins, GhGRAM5 and GhGRAM35. GhGRAM5 also interacts with the transcription factor GhTTG1, while GhGRAM35 interacts with the transcription factors GhHOX1 and GhHD1. Co-expression of GhGRAM31 and GhGRAM35 was able to promote GhHD1 transcription activity in cotton protoplasts. Our results provide new insights into the biological function of the GRAM-domain protein family in cotton, and selected genes have the potential to be utilized in future programs for the genetic improvement of fibers.

Phosphate deficiency enhances cotton resistance to Verticillium dahliae through activating jasmonic acid biosynthesis and phenylpropanoid pathway.

Living in natural environment, plants often suffer from various biotic and abiotic stresses. Phosphate deficiency is a common factor affecting crop production in field, while pathogen invasion is another serious problem. Here we report that Pi-deficient cotton plants exhibit enhanced resistance to Verticillium dahliae. Transcriptomic and histochemical analysis revealed that cotton phenylpropanoid pathway was activated under phosphate deficiency, including lignin and flavonoid biosynthesis. Metabolomic data showed that Pi-deficient cotton accumulates many flavonoids metabolites and displays obvious anti-fungi activity in terms of methanolic extract. Additionally, JA biosynthesis was activated under phosphate deficiency and the Pi-deficiency induced disease resistance was significantly attenuated in GhAOS knock down plants. Taken together, our study demonstrated that phosphate deficiency enhanced cotton resistance to V. dahliae through activating phenylpropanoid pathway and JA biosynthesis, providing new insights into how phosphate deficiency affects plant disease resistance.

ABA signaling is negatively regulated by GbWRKY1 through JAZ1 and ABI1 to affect salt and drought tolerance.

KEY MESSAGE: GbWRKY1 can function as a negative regulator of ABA signaling via JAZ1 and ABI1, with effects on salt and drought tolerance. WRKY transcription factors play important roles in plant development and stress responses. GbWRKY1 was initially identified as a defense-related gene in cotton and negatively regulates the response to fungal pathogens by activating the expression of JAZ1. Here, we characterized the role of GbWRKY1, an orthologue of the Arabidopsis gene AtWRKY75, in abiotic stress (salt and drought) and established novel connection between JAZ1 and ABA signaling in Arabidopsis. GbWRKY1 is nucleus localized and its expression is significantly induced by treatment with ABA and osmotic stresses NaCl and PEG. Increased levels of expression of GbWRKY1 in transgenic Arabidopsis enhance sensitivity to salt and drought as revealed by seed germination tests and soil stress experiments. Similarly, GbWRKY1 overexpression cotton plants also display increased sensitivity to PEG treatment and drought. Expression analysis shows that the induction of two ABA responsive genes, RAB18 and RD29A by NaCl, mannitol, and ABA treatment is significantly impaired in GbWRKY1 overexpression Arabidopsis lines. GbWRKY1 overexpression Arabidopsis displays a strong ABA-insensitive phenotype at both germination and early stages of seedling development. Further genetic evidence suggested that the ABA-insensitive phenotype of GbWRKY1 overexpression Arabidopsis was dependent on JAZ1, and overexpression of JAZ1 also displayed an ABA-insensitive phenotype. In addition, yeast two hybrid and bimolecular fluorescence complementation assays showed that JAZ1 directly interacts with ABI1, a key negative regulator of ABA signaling. We, therefore, demonstrate that GbWRKY1 acts as a negative regulator of ABA signaling, through an interaction network involving JAZ1 and ABI1, to regulate salt and drought tolerance.

The cotton HD-Zip transcription factor GhHB12 regulates flowering time and plant architecture via the GhmiR157-GhSPL pathway.

Domestication converts perennial and photoperiodic ancestral cotton to day-neutral cotton varieties, and the selection of short-season cotton varieties is one of the major objectives of cotton breeding. However, little is known about the mechanism of flowering time in cotton. Here, we report a cotton HD-ZIP I-class transcription factor (GhHB12) specifically expressed in axillary buds, which antagonisticlly interacts with GhSPL10/13 to repress the expression of GhFT, GhFUL, and GhSOC1, resulting in bushy architecture and delayed flowering under long-day conditions. We found that GhHB12-mediated ancestral upland cotton phenotypes (bushy architecture and delayed flowering) could be rescued under short-day conditions. We showed that overexpressing of GhrSPL10 partially rescues the bushy architecture and delayed flowering phenotypes, while overexpression of GhmiR157 reinforced these phenotypes in GhHB12-overexpressing plants. This study defines a regulatory module which regulates cotton architecture, phase transition and could be applied in the breeding of early maturing cotton varieties.

Cotton WRKY1 mediates the plant defense-to-development transition during infection of cotton by Verticillium dahliae by activating JASMONATE ZIM-DOMAIN1 expression.

Plants have evolved an elaborate signaling network to ensure an appropriate level of immune response to meet the differing demands of developmental processes. Previous research has demonstrated that DELLA proteins physically interact with JASMONATE ZIM-DOMAIN1 (JAZ1) and dynamically regulate the interaction of the gibberellin (GA) and jasmonate (JA) signaling pathways. However, whether and how the JAZ1-DELLA regulatory node is regulated at the transcriptional level in plants under normal growth conditions or during pathogen infection is not known. Here, we demonstrate multiple functions of cotton (Gossypium barbadense) GbWRKY1 in the plant defense response and during development. Although GbWRKY1 expression is induced rapidly by methyl jasmonate and infection by Verticillium dahliae, our results show that GbWRKY1 is a negative regulator of the JA-mediated defense response and plant resistance to the pathogens Botrytis cinerea and V. dahliae. Under normal growth conditions, GbWRKY1-overexpressing lines displayed GA-associated phenotypes, including organ elongation and early flowering, coupled with the down-regulation of the putative targets of DELLA. We show that the GA-related phenotypes of GbWRKY1-overexpressing plants depend on the constitutive expression of Gossypium hirsutum GhJAZ1. We also show that GhJAZ1 can be transactivated by GbWRKY1 through TGAC core sequences, and the adjacent sequences of this binding site are essential for binding specificity and affinity to GbWRKY1, as revealed by dual-luciferase reporter assays and electrophoretic mobility shift assays. In summary, our data suggest that GbWRKY1 is a critical regulator mediating the plant defense-to-development transition during V. dahliae infection by activating JAZ1 expression.