Project description:Background: Boron (B)-deficiency is a widespread problem in many crops, including Citrus. MicroRNAs (miRNAs) play important roles in nutrient deficiencies. However, little is known on B-deficiency-responsive miRNAs in plants. In this study, we first identified miRNAs and their expression pattern in B-deficient Citrus sinensis roots by Illumina sequencing in order to identify miRNAs that might be involved in the tolerance of plants to B-deficiency. Results: We isolated 52 (40 known and 12 novel) up-regulated and 82 (72 known and 10 novel) down-regulated miRNAs from B-deficient roots, demonstrating remarkable metabolic flexibility of roots, which might contribute to the tolerance of plants to B-deficiency. A model for the possible roles of miRNAs in the tolerance of roots to B-deficiency was proposed. miRNAs might regulate the adaptations of roots to B-deficiency through following several aspects: (a) inactivating reactive oxygen species (ROS) signaling and scavenging through up-regulating miR474 and down-regulating miR782 and miR843; (b) increasing lateral root number by lowering miR5023 expression and maintaining a certain phenotype favorable for B-deficiency-tolerance by increasing miR394 expression; (c) enhancing cell transport by decreasing the transcripts of miR830, miR5266 and miR3465; (d) improving osmoprotection (miR474) and regulating other metabolic reactions (miR5023 and miR821). Other miRNAs such as miR472 and miR2118 in roots increased in response to B-deficiency, thus decreasing the expression of their target genes, which are involved in disease resistance, and hence, the disease resistance of roots. Conclusions: Our work demonstrates the possible roles of miRNAs and related mechanisms in the response of plant roots to B-deficiency.
Project description:Background: Magnesium (Mg)-deficiency occurs most frequently in strongly acidic, sandy soils. Citrus are grown mainly on acidic and strong acidic soils. Mg-deficiency causes poor fruit quality and low fruit yield in some Citrus orchards. For the first time, we investigated Mg-deficiency-responsive miRNAs in ‘Xuegan’ (Citrus sinensis) roots using Illumina sequencing in order to obtain some miRNAs presumably responsible for Citrus Mg-deficiency tolerance. Results: We obtained 101 (69) miRNAs with increased (decreased) expression from Mg-starved roots. Our results suggested that the adaptation of Citrus roots to Mg-deficiency was related to the several aspects: (a) inhibiting root respiration and related gene expression via inducing miR158 and miR2919; (b) enhancing antioxidant system by down-regulating related miRNAs (miR780, miR6190, miR1044, miR5261 and miR1151) and the adaptation to low-phosphorus (miR6190); (c) activating transport-related genes by altering the expression of miR6190, miR6485, miR1044, miR5029 and miR3437; (d) elevating protein ubiquitination due to decreased expression levels of miR1044, miR5261, miR1151 and miR5029; (e) maintaining root growth by regulating miR5261, miR6485 and miR158 expression; and (f) triggering DNA repair (transcription regulation) by regulating miR5176 and miR6485 (miR6028, miR6190, miR6485, miR5621, miR160 and miR7708) expression. Mg-deficiency-responsive miRNAs involved in root signal transduction also had functions in Citrus Mg-deficiency tolerance. Conclusions: We obtained several novel Mg-deficiency-responsive miRNAs (i.e., miR5261, miR158, miR6190, miR6485, miR1151 and miR1044) possibly contributing to Mg-deficiency tolerance. These results revealed some novel clues on the miRNA-mediated adaptation to nutrient deficiencies in higher plants.
Project description:After long-term magnesium-deficiency treatment, 2D electrophoresis and mass spectrum were conducted to investigate different proteiomic profile in Citrus sinensis roots and leaves samples.
Project description:Limited data are available on the impacts of copper (Cu)-pH-interaction-responsive genes in roots. Citrus sinensis seedlings were treated with 300 (Cu-toxicity) or 0.5 uM (control) CuCl2 x pH 3.0 or 4.8 for 17 weeks. Thereafter, we investigated the impacts of Cu-pH interactions on transcriptomics in roots.
Project description:After long-term different boron and aluminum treatment, 2D electrophoresis and mass spectrum were conducted to investigate different proteiomic profile in Citrus sinensis roots samples.
Project description:In China, magnesium (Mg)-deficiency often occurs in citrus orchards, and is responsible for the loss of yield and poor fruit quality. However, very limited data are available on Mg-deficiency-responsive microRNAs (miRNAs) in higher plants. Using Illumina sequencing, we isolated 93 (91 known and 2 novel) up- and 90 (83 known and 7 novel) down-regulated miRNAs from Mg-deficient Citrus sinensis leaves. In addition to the remarkable metabolic flexibility as indicated by the great alteration of miRNA expression, the adaptive responses of leaf miRNAs to Mg-deficiency might also involve the following aspects: (a) accelerating protein turnover and amino acid biosynthesis by repressing the expression of miR2919, miR7812, miR5904 and miR5742; (b) up-regulating stress-related genes by down-regulating miR2919, miR164 and miR7812; (c) enhancing cell transport due to decreased expression of miR2919, miR3946, miR7533, miR1222, miR779, miR6143 and miR2868 and increased expression of miR395, miR1077, miR1160 and miR8019; (d) activating lipid metabolism-related genes by repressing miR158, miR1222, miR7533 and miR3946; (e) inducing cell wall-related genes by decreasing miR7533, miR779 and miR2868 expression; and (f) maintaing primary meristems by down-regulating miR6135. To conclude, we identified some candidate miRNAs that might contribute to Mg-deficiency tolerance. Our results are usefult not only for increasing our understaning of the molecular mechanisms on plant Mg-deficiency tolerance at post-transcriptional level, but also for obtaining the key miRNAs for plant Mg-deficiency tolerance.
Project description:Background: MicroRNAs play important roles in the adaptive responses of plants to nutrient deficiencies. Here, we sequenced two small RNA libraries from B-deficient and -sufficient (control) Citrus sinensis leaves, respectively, using Illumina sequencing in order to identify the potential miRNAs related to the tolerance of citrus to B-deficiency. Results: Ninety one (83 known and 8 novel) up- and 81 (75 known and 6 novel) downregulated miRNAs were isolated from B-deficient leaves. The great alteration of miRNA expression might contribute to the tolerance of citrus to B-deficiency. The adaptive responses of miRNAs to B-deficiency might related to several aspects: (a) attenuation of plant growth and development by repressing auxin signaling due to decreased TIR1 level and ARF-mediated gene expression by altering the expression of miR393, miR160 and miR3946; (b) maintaining leaf phenotype and enhancing the stress tolerance by up-regulating NACs targeted by miR159, miR782, miR3946 and miR7539; (c) activation of the stress responses and antioxidant system through down-regulating the expression of miR164, miR6260, miR5929, miR6214, miR3946 and miR3446; (d) decreasing the expression of major facilitator superfamily protein genes targeted by miR5037, thus lowering B export from plants. Also, B-deficiency-induced downregulation of miR408 might play a role in plant tolerance to B-deficiency by regulating Cu homeostasis and enhancing superoxide dismutase activity. Conclusions: Our study reveals some novel responses of citrus to B-deficiency, which increase our understanding of the adaptive mechanisms of citrus to B-deficiency at the miRNA (post-transcriptional) level.
Project description:Background: Limited data are available on aluminum (Al)-toxicity-induced alterations of gene profiles in woody plants. Seedlings of Al-tolerant Citrus sinensis and Al-intolerant Citrus grandis were fertigated with nutrient solution containing 0 and 1.0 mM AlCl3â?¢6H2O. Thereafter, we investigated the Al-toxicity-induced alterations of transcriptomics in roots by RNA-Seq. Results: Using RNA-seq, we isolated 1293 (990) up- and 1377 (915) downregulated genes from Al-treated C. grandis (C. sinensis) roots. Clearly, gene expression was less affected by Al-toxicity in C. sinensis roots than in C. grandis ones. Several Al-toxicity-responsive genes homologous to known Al-tolerance genes: Al-activated malate transporter, multidrug and toxic compound extrusion (MATE), IRON REGULATED/ferroportin 1, sensitive to proton rhizotoxicity 1 and monogalactosyldiacylglycerol synthase were identified in citrus roots. However, Al-induced upregulation of all these genes was stronger in C. grandis roots than in C. sinensis ones except for MATEs. Genes related to signal transduction, and sulfur transport and metabolism might also play a role in the higher Al-tolerance of C. sinensis. Conclusions: This is the first comparative investigation of transcriptomic responses in Al-treated citrus roots. There were common and unique mechanisms for citrus Al-tolerance. These results provide a platform for further investigating the roles of genes possibly responsible for citrus Al-tolerance. Examination of mRNA levels in control and Al-treatment roots of C. grandis and C. sinensis with two biological replicates were generated by deep sequencing, using Illumina HiSeq 2000 device.
Project description:Background: Limited data are available on aluminum (Al)-toxicity-induced alterations of gene profiles in woody plants. Seedlings of Al-tolerant Citrus sinensis and Al-intolerant Citrus grandis were fertigated with nutrient solution containing 0 and 1.0 mM AlCl3•6H2O. Thereafter, we investigated the Al-toxicity-induced alterations of transcriptomics in roots by RNA-Seq. Results: Using RNA-seq, we isolated 1293 (990) up- and 1377 (915) downregulated genes from Al-treated C. grandis (C. sinensis) roots. Clearly, gene expression was less affected by Al-toxicity in C. sinensis roots than in C. grandis ones. Several Al-toxicity-responsive genes homologous to known Al-tolerance genes: Al-activated malate transporter, multidrug and toxic compound extrusion (MATE), IRON REGULATED/ferroportin 1, sensitive to proton rhizotoxicity 1 and monogalactosyldiacylglycerol synthase were identified in citrus roots. However, Al-induced upregulation of all these genes was stronger in C. grandis roots than in C. sinensis ones except for MATEs. Genes related to signal transduction, and sulfur transport and metabolism might also play a role in the higher Al-tolerance of C. sinensis. Conclusions: This is the first comparative investigation of transcriptomic responses in Al-treated citrus roots. There were common and unique mechanisms for citrus Al-tolerance. These results provide a platform for further investigating the roles of genes possibly responsible for citrus Al-tolerance.