Pumpkin CmHKT1;1 Controls Shoot Na⁺ Accumulation via Limiting Na⁺ Transport from Rootstock to Scion in Grafted Cucumber.
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PROVIDER: S-EPMC6165489 | BioStudies |
REPOSITORIES: biostudies
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Project description:During early periods of salt stress, reduced stomatal opening can prevent water loss and wilting. Abscisic acid (ABA) signal plays an important role in this process. Here, we show that cucumber grafted onto pumpkin exhibits rapid stomatal closure, which helps plants to adapt to osmotic stress caused by salinity. Increased ABA contents in the roots, xylem sap, and leaves were evaluated in two grafting combinations (self-grafted cucumber and cucumber grafted onto pumpkin rootstock). The expression levels of ABA biosynthetic or signaling related genes NCED2 (9-cis-epoxycarotenoid dioxygenase gene 2), ABCG22 (ATP-binding cassette transporter genes 22), PP2C (type-2C protein phosphatases), and SnRK2.1 (sucrose non-fermenting 1-related protein kinases 2) were investigated. Results showed that a root-sourced ABA signal led to decreased stomatal opening and transpiration in the plants grafted onto pumpkin. Furthermore, plants grafted onto pumpkin had increased sensitivity to ABA, compared with self-grafted cucumbers. The inhibition of ABA biosynthesis with fluridon in roots increased the transpiration rate (Tr) and stomatal conductance (Gs) in the leaves. Our study demonstrated that the roots of pumpkin increases the sensitivity of the scion to ABA delivered from the roots to the shoots, and enhances osmotic tolerance under NaCl stress. Such a mechanism can be greatly exploited to benefit vegetable production particularly in semiarid saline regions.
| S-EPMC6859870 | BioStudies
Project description:Plant salt tolerance can be improved by grafting onto salt-tolerant rootstocks. However, the underlying signaling mechanisms behind this phenomenon remain largely unknown. To address this issue, we used a range of physiological and molecular techniques to study responses of self-grafted and pumpkin-grafted cucumber plants exposed to 75 mM NaCl stress. Pumpkin grafting significantly increased the salt tolerance of cucumber plants, as revealed by higher plant dry weight, chlorophyll content and photochemical efficiency (Fv/Fm), and lower leaf Na+ content. Salinity stress resulted in a sharp increase in H2O2 production, reaching a peak 3 h after salt treatment in the pumpkin-grafted cucumber. This enhancement was accompanied by elevated relative expression of respiratory burst oxidase homologue (RBOH) genes RbohD and RbohF and a higher NADPH oxidase activity. However, this increase was much delayed in the self-grafted plants, and the difference between the two grafting combinations disappeared after 24 h. The decreased leaf Na+ content of pumpkin-grafted plants was achieved by higher Na+ exclusion in roots, which was driven by the Na+/H+ antiporter energized by the plasma membrane H+-ATPase, as evidenced by the higher plasma membrane H+-ATPase activity and higher transcript levels for PMA and SOS1. In addition, early stomatal closure was also observed in the pumpkin-grafted cucumber plants, reducing water loss and maintaining the plant's hydration status. When pumpkin-grafted plants were pretreated with an NADPH oxidase inhibitor, diphenylene iodonium (DPI), the H2O2 level decreased significantly, to the level found in self-grafted plants, resulting in the loss of the salt tolerance. Inhibition of the NADPH oxidase-mediated H2O2 signaling in the root also abolished a rapid stomatal closure in the pumpkin-grafted plants. We concluded that the pumpkin-grafted cucumber plants increase their salt tolerance via a mechanism involving the root-sourced respiratory burst oxidase homologue-dependent H2O2 production, which enhances Na+ exclusion from the root and promotes an early stomatal closure.
| S-EPMC6009698 | BioStudies
Project description:The use of heterografts is widely applied for the production of several important commercial crops, but the molecular mechanism of graft union formation remains poorly understood. Here, cucumber grafted onto pumpkin was used to study graft union development, and genome-wide tempo-spatial gene expression at the graft interface was comprehensively investigated. Histological analysis suggested that resumption of the rootstock growth occurred after both phloem and xylem reconnection, and the scion showed evident callus production compared with the rootstock 3 days after grafting. Consistently, transcriptome data revealed specific responses between the scion and rootstock in the expression of genes related to cambium development, the cell cycle, and sugar metabolism during both vascular reconnection and healing, indicating distinct mechanisms. Additionally, lower levels of sugars and significantly changed sugar enzyme activities at the graft junction were observed during vascular reconnection. Next, we found that the healing process of grafted etiolated seedlings was significantly delayed, and graft success, xylem reconnection, and the growth of grafted plants were enhanced by exogenous glucose. This demonstrates that graft union formation requires the correct sugar content. Furthermore, we also found that graft union formation was delayed with a lower energy charge by the target of rapamycin (TOR) inhibitor AZD-8055, and xylem reconnection and the growth of grafted plants were enhanced under AZD-8055 with exogenous glucose treatment. Taken together, our results reveal that sugars play a positive role in graft union formation by promoting the growth of cucumber/pumpkin and provide useful information for understanding graft union healing and the application of heterografting in the future.
| S-EPMC8245404 | BioStudies
Project description:Melon (Cucumis melo) is one of the top 10 fruits in the world, and its production often suffers due to soil-borne diseases. Grafting is an effective way to solve this problem. However, graft incompatibility between scion and rootstock limits the application of melon grafting. In this study, the melon was grafted onto eight Cucurbitaceae species (cucumber, pumpkin, melon, luffa, wax gourd, bottle gourd, bitter gourd, and watermelon), and graft compatibility evaluation and anatomical observation were conducted. Taking melon homo-grafted plants as control, melon grafted onto cucumber and pumpkin rootstocks was compatible, while melon grafted onto luffa, wax gourd, bottle gourd, bitter gourd, and watermelon rootstocks was incompatible based on the scion dry weight on day 42 after grafting. Meanwhile, we found that starch–iodine staining of scion stem base is an index to predict graft compatibility earlier, on day 14 after grafting. Further, microsection observations showed that there was more cell proliferation at graft junction of melon hetero-grafted combinations; vascular reconnection occurred in all graft combinations. However, excess callose deposited at graft junction resulted in the blockage of photosynthate transport, thus, leading to starch accumulation in scion stem base, and finally graft incompatibility. In addition, undegraded necrotic layer fragments were observed at graft junctions of melon grafted onto incompatible bitter gourd and watermelon rootstocks. The above results provide clues for the selection and breeding of compatible Cucurbitaceae rootstocks of melon and demonstrate that starch accumulation in scion base and callose deposition at graft junction is associated with melon graft compatibility.
| S-EPMC8563831 | BioStudies
Project description:Background:Quantitative real-time PCR (qRT-PCR) is a commonly used high-throughput technique to measure mRNA transcript levels. The accuracy of this evaluation of gene expression depends on the use of optimal reference genes. Cucumber-pumpkin grafted plants, made by grafting a cucumber scion onto pumpkin rootstock, are superior to either parent plant, as grafting conveys many advantages. However, although many reliable reference genes have been identified in both cucumber and pumpkin, none have been obtained for cucumber-pumpkin grafted plants. Methods:In this work, 12 candidate reference genes, including eight traditional genes and four novel genes identified from our transcriptome data, were selected to assess their expression stability. Their expression levels in 25 samples, including three cucumber and three pumpkin samples from different organs, and 19 cucumber-pumpkin grafted samples from different organs, conditions, and varieties, were analyzed by qRT-PCR, and the stability of their expression was assessed by the comparative ?Ct method, geNorm, NormFinder, BestKeeper, and RefFinder. Results:The results showed that the most suitable reference gene varied dependent on the organs, conditions, and varieties. CACS and 40SRPS8 were the most stable reference genes for all samples in our research. TIP41 and CACS showed the most stable expression in different cucumber organs, TIP41 and PP2A were the optimal reference genes in pumpkin organs, and CACS and 40SRPS8 were the most stable genes in all grafted cucumber samples. However, the optimal reference gene varied under different conditions. CACS and 40SRPS8 were the best combination of genes in different organs of cucumber-pumpkin grafted plants, TUA and RPL36Aa were the most stable in the graft union under cold stress, LEA26 and ARF showed the most stable expression in the graft union during the healing process, and TIP41 and PP2A were the most stable across different varieties of cucumber-pumpkin grafted plants. The use of LEA26, ARF and LEA26+ARF as reference genes were further verified by analyzing the expression levels of csaCYCD3;1, csaRUL, cmoRUL, and cmoPIN in the graft union at different time points after grafting. Discussion:This work is the first report of appropriate reference genes in grafted cucumber plants and provides useful information for the study of gene expression and molecular mechanisms in cucumber-pumpkin grafted plants.
| S-EPMC6475253 | BioStudies
Project description:Salicylic acid (SA) has been proven to be a multifunctional signaling molecule that participates in the response of plants to abiotic stresses. In this study, we used cold-sensitive cucumber and cold-tolerant pumpkin as experimental materials to examine the roles of SA in root-shoot communication responses to aerial or/and root-zone chilling stress in own-root and hetero-root grafted cucumber and pumpkin plants. The results showed that pumpkin (<i>Cm</i>) rootstock enhanced the chilling tolerance of grafted cucumber, as evidenced by the observed lower levels of electrolyte leakage (EL), malondialdehyde (MDA), and higher photosynthetic rate (Pn) and gene expression of Rubisco activase (RCA). However, cucumber (<i>Cs</i>) rootstock decreased the chilling tolerance of grafted pumpkins. <i>Cs/Cm</i> plants showed an increase in the mRNA expression of C-repeat-binding factor (<i>CBF1</i>), an inducer of <i>CBF</i> expression (<i>ICE1</i>), and cold-responsive (<i>COR47</i>) genes and <i>CBF1</i> protein levels in leaves under 5/25 and 5/5°C stresses, or in roots under 25/5 and 5/5°C stresses, respectively, compared with the <i>Cs/Cs</i>. Chilling stress increased the endogenous SA content and the activity of phenylalanine ammonia-lyase (PAL), and the increase in SA content and activity of PAL in <i>Cs/Cm</i> plants was much higher than in <i>Cs/Cs</i> plants. Transcription profiling analysis revealed the key genes of SA biosynthesis, <i>PAL</i>, <i>ICS</i>, and <i>SABP2</i> were upregulated, while <i>SAMT</i>, the key gene of SA degradation, was downregulated in <i>Cs/Cm</i> leaves, compared with <i>Cs/Cs</i> leaves under chilling stress. The accumulation of SA in the <i>Cs/Cm</i> leaves was mainly attributed to an increase in SA biosynthesis in leaves and that in transport from roots under aerial and root-zone chilling stress, respectively. In addition, exogenous SA significantly upregulated the expression level of cold-responsive (<i>COR</i>) genes, enhanced actual photochemical efficiency (<i>Φ</i> <sub>PSII</sub>), maximum photochemical efficiency (<i>F</i> <sub>v</sub>/<i>F</i> <sub>m</sub>), and Pn, while decreased EL, MDA, and CI in grafted cucumber. These results suggest that SA is involved in rootstock-scion communication and grafting-induced chilling tolerance by upregulating the expression of <i>COR</i> genes in cucumber plants under chilling stress.
| S-EPMC8264795 | BioStudies
Project description:In viticulture, rootstocks are essential to cope with edaphic constraints. They can also be used to modulate scion growth and development to help improve berry yield and quality. The rootstock contribution to scion growth is not fully understood. Since nitrogen (N) is a significant driver of grapevine growth, rootstock properties associated with N uptake and transport may play a key role in the growth potential of grafted grapevines. We evaluated N uptake and transport in a potted system using two grapevines rootstocks [Riparia Gloire (RG) and 1103 Paulsen (1103P)] grafted to Pinot noir (Pommard clone) scion. Combining results of nitrate induction and steady-state experiments at two N availability levels, we observed different responses in the uptake and utilization of N between the two rootstocks. The low vigor rootstock (RG) exhibited greater nitrate uptake capacity and nitrate assimilation in roots after nitrate resupply than the more vigorous 1103P rootstock. This behavior may be attributed to a greater root carbohydrate status observed in RG for both experiments. However, 1103P demonstrated a higher N translocation rate to shoots regardless of N availability. These distinct rootstock behaviors resulted in significant differences in biomass allocation between roots and shoots under N-limited conditions, although the overall vine biomass was not different. Under sufficient N supply, differences between rootstocks decreased but 1103P stored more N in roots, which may benefit growth in subsequent growing seasons. Overall, greater transpiration of vines grafted to 1103P rootstock causing higher N translocation to shoots could partially explain its known growth-promoting effect to scions under low and high N availability, whereas the low vigor typically conferred to scions by RG may result from the combination of lower N translocation to shoots and a greater allocation of biomass toward roots when N is low.
| S-EPMC7847936 | BioStudies
Project description:: Grafting has been widely used to improve plant growth and tolerance in crop production, as well as for clarifying systemic mRNA signaling from donor to recipient tissues in organ-to-organ communication. In this study, we investigated graft partner interaction mechanisms of Cucumis sativus (Csa) and Cucurbita moschata (Cmo) using a large-scale endogenous mRNA transport. The results indicated that most mobile transcripts followed an allocation pathway from source to sink. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that mRNA mobility functions are universally common and individually specific. Identification of mRNA mobility between distant tissues in heterografts with RT-PCR (reverse transcription PCR), RT-qPCR (reverse transcriptional quantitative real time PCR), and clone sequencing were used to estimate 78.75% of selected mobile transcripts. Integration of bioinformatic analysis and RT-qPCR identification allowed us to hypothesize a scion-to-rootstock-to-scion feedback signal loop of Csa move-down and Cmo move-up mRNAs, where Csa scion move-down mRNAs were involved in carbon fixation and biosynthesis of amino acid pathways, and Cmo root received Csa move-down mRNA and then delivered the corresponding Cmo upward mRNA to scion to improve photosynthesis of cucumber scion. This formed a feedback signal loop of scion-to-rootstock-to scion to explain why pumpkin rootstock enhanced cucumber production in the industry, which was utilized for organ communication and mediates photosynthesis processes in heterograft cucurbit crops.
| S-EPMC7432352 | BioStudies
Project description:Cucumber (Cucumis sativus L.) is an economically important vegetable cultivated all over the world. Grafting can produce bloomless or sparse-bloom cucumber, which is welcomed by increasing consumers. Bloom granule is tine glandular hair, which is hard and rare studied on its formation and related genes. Mutifunctional RNA-seq is a recently developed analytical approach for transcriptome profiling via high-throughput sequencing and has been recently applied to a wide variety of organisms, which provide us reliable technical means detect bloom formation and related genes. In this study, we chose a cucumber inbred line (Shannong No.5) and two pumpkin rootstock lines as materials, and constructed four tested cucumbers, grew plants in “Yamazaki cucumber nutrient solution formula” prepared by deionized water, treated plants with or without 1.7mM potassium silicate 2 hours before collecting pericarp. Each treatment were duplicated twice.16 cDNA libraries were constructed from pericarp of a cucumber inbred line (own-rooted cucumber), C/C (self-grafted cucumber), M/C (More bloom, cucumber grafted onto “3225” rootstock) and L/C(Less bloom, cucumber grafted onto “3212” rootstock). We obtained 17,215,769~17,529,047 high quality reads, and 18,804~19,358 genes from each sample. All reads can be mapped to the cucumber genome (Version 2). By RPKM comparing, we got 38 comparing combinations with differentially expressed genes (DEGs), obtained 38 significantly expressed combinations by FDR≤0.001 and the absolute value of log2Ratio≥1 as the thresholds. These results suggest that there are many differences and genes expression mode among effects of grafting or added silicon. This study addresses a preliminary analysis and offers a foundation for future genomic research in the bloom formation of cucumber. Overall design: Own-rooted cucumber,self-grafted cucumber and cucumber grafted onto two pumpkin rootstock lines, cultivated by deionized water nutrient solution with 1.7mM silicon added or not; RNA-Seq on cucumbers pericarp, analyse the data, and get differencially expressed genes
2020-04-02 | GSE79829 | GEO
Project description:To understand the roles of Malus rootstock, scion, and their interaction in Cd accumulation and tolerance, four scion/rootstock combinations consisting of the apple cultivars "Hanfu" (HF) and "Fuji" (FJ) grafted onto M. baccata (Mb) or M. micromalus "qingzhoulinqin" (Mm) rootstocks differing in relative Cd tolerance were exposed either to 0 µM or 50 µM CdCl2 for 18 d. Cd accumulation and tolerance in grafted Malus plants varied within rootstock, scion, and rootstock-scion interaction. Cd-induced decreases in photosynthesis, photosynthetic pigment level, and biomass were lower for HF grafted onto Mb than those for HF grafted onto Mm. Reductions in growth and photosynthetic rate were always the lowest for HF/Mb. Cd concentration, bioconcentration factor (BCF), and translocation factor (Tf ) were always comparatively higher in HF and FJ grafted onto rootstock Mm than in HF and FJ grafted on Mb, respectively. When HF and FJ were grafted onto the same rootstock, the root Cd concentrations were always higher in HF than FJ, whereas the shoot Cd concentrations displayed the opposite trend. The shoot Cd concentrations and Tf were lower for HF/Mb than the other scion/rootstock combinations. Rootstock, scion, and rootstock-scion interaction also affected subcellular Cd distribution. Immobilization of Cd in the root cell walls may be a primary Cd mobility and toxicity reduction strategy in Malus. The rootstock and scion also had statistically significant influences on ROS level and antioxidant activity. Cd induced more severe oxidative stress in HF and FJ grafted onto Mm than it did in HF and FJ grafted onto Mb. Compared with FJ, HF had lower foliar O2 -, root H2O2, and root and leaf MDA levels, but higher ROS-scavenging capacity. The rootstock, scion, and rootstock-scion interaction affected the mRNA transcript levels of several genes involved in Cd uptake, transport, and detoxification including HA7, FRO2-like, NRAMP1, NRAMP3, HMA4, MT2, NAS1, and ABCC1. Hence, the responses of grafted Malus plants to Cd toxicity vary with rootstock, scion, and rootstock-scion interaction.
| S-EPMC7457089 | BioStudies