Small RNAs sequencing in sweet sorghum under cadmium stress
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ABSTRACT: Four small RNA libraries from two contrasting sweet sorghum genotypes were sequenced. In this study, One hundred and ninety-five conserved miRNAs belonging to 56 families and 25 putative novel miRNAs from 28 precursors were identified, among which 38 conserved and 24 novel miRNAs were differentially expressed under Cd stress and/or between H18 and L69. Two groups of them: miR169p/q-nov_23 and miR408 were further focused through the coexpression analysis and might be involved in Cd transport, cytoskeleton activity and cell wall construction by regulating their targets. This study presents new insights into the regulatory roles of miRNAs in Cd accumulation and tolerance in sweet sorghum and will help to develop high-Cd accumulation or high Cd-resistant germplasm of sweet sorghum through molecular breeding and/or genetic engineering approaches.
Project description:Sweet sorghum has emerged as a promising source of bioenergy mainly due to its high biomass and high soluble sugar yield in stems. Studies have shown that loss-of-function Dry locus alleles have been selected during sweet sorghum domestication, and decapitation can further boost sugar accumulation in sweet sorghum, indicating that the potential for improving sugar yields is yet to be fully realized. To maximize sugar accumulation, it is essential to gain a better understanding of the mechanism underlying the massive accumulation of soluble sugars in sweet sorghum stems in addition to the Dry locus. We performed a transcriptomic analysis upon decapitation of near-isogenic lines for mutant (d, juicy stems, and green leaf midrib) and functional (D, dry stems and white leaf midrib) alleles at the Dry locus. Our analysis revealed that decapitation suppressed photosynthesis in leaves, but accelerated starch metabolic processes in stems. SbbHLH093 negatively correlates with sugar levels supported by genotypes (DD vs. dd), treatments (control vs. decapitation), and developmental stage post anthesis (3d vs.10d). D locus gene SbNAC074A and other programmed cell death-related genes were downregulated by decapitation, while sugar transporter-encoding gene SbSWEET1A was induced. Both SbSWEET1A and Invertase 5 were detected in phloem companion cells by RNA in situ assay. Loss of the SbbHLH093 homolog, AtbHLH093, in Arabidopsis led to a sugar accumulation increase. This study provides new insights into sugar accumulation enhancement in bioenergy crops, which can be potentially achieved by reducing reproductive sink strength and enhancing phloem unloading.
Project description:The N6-methyladenosine (m6A) modification is the most common internal post-transcriptional modification, with important regulatory effects on RNA export, splicing, stability,and translation. However, the effects of m6A modifications on the resistance of sweet sorghum to salt stress remain unclear. In this study, we mapped the m6A modifications in two sorghum inbred lines (salt-tolerant M-81E and salt-sensitive Roma) that differ regarding salt tolerance. Dynamic changes to m6A modifications in sweet sorghum were identified in response to salt stress. Our data suggest that the differences in the m6A modifications between salt-tolerant and salt-sensitive sweet sorghum might contribute to the diversity in salt tolerance.
Project description:As no commercial array is available for sorghum microarray analysis, we designed an array based on the annotation of Sbi1.4 gene set and the available 209,835 sorghum ESTs from the NCBI EST database. The array will be used for investigating the expression divergence between grain and sweet sorghum lines under normal and sucrose treatments The expression analysis was carried out using 14-day old whole seedlings from both grain and sweet sorghum lines. Three samples from sucrose treatment (0h, 2h and 6h) for each line were collected for the analysis . Two biological replicates were carried out for both control and sucrose treatments, resulting in a dataset of 12 microarrays.
Project description:Salt stress has become one of the main abiotic stress factors restricting agricultural production worldwide. Sweet sorghum is an important salt and drought tolerant feed and energy crop. Its salt tolerance mechanism has not been widely studied. With the development of transcriptome sequencing technology, it is possible to study the molecular mechanism of sweet sorghum salt tolerance. The purpose of this study was to further reveal the potential salt-tolerant molecular mechanisms of sweet sorghum through high-throughput sequencing analysis of the transcriptome. Finally, through high-throughput sequencing, we read approximately 54.4G of raw base and 53.7G of clean base in total, and used FastQC to assign a quality score (Q) to each base in the read using a similar phred algorithm, Analysis shows that the data is highly credible. We conclude that RNA-based transcriptome characterization will accelerate the study of genetics and molecular biology of sweet sorghum salt tolerance mechanisms and provide a framework for this.
Project description:As no commercial array is available for sorghum microarray analysis, we designed an array based on the annotation of Sbi1.4 gene set and the available 209,835 sorghum ESTs from the NCBI EST database. The array will be used for investigating the expression divergence between grain and sweet sorghum lines under normal and sucrose treatments
Project description:We report transcriptome profiling from three developing stages of middle internode in sweet sorghum. Samples were harvested at Booting, milky stages and physiological maturity.
Project description:We report transcriptome profiling from three developing stages of middle internode in Hybrid sweet sorghum. Samples were harvested at Booting, milky stages and physiological maturity.
Project description:Although poplars are good candidates for the phytoremediation of cadmium (Cd)-polluted soils and sulfur is a key player in modulating Cd detoxification and accumulation in plants, the physiological and molecular mechanisms underlying sulfur-mediated Cd accumulation remain largely unknown. To investigate physiological and transcriptomic regulation mechanisms of poplars in response to Cd exposure and different sulphate (S) supply levels, Populus deltoides saplings were exposed to either 0 or 50 µM Cd together with one of low, moderate and high S levels. Cd was accumulated in the leaves of Cd-exposed poplars under moderate S condition, and its accumulation is inhibited by low S but tended to increase by high S. Sulfur nutrition became deficient in Cd-treated leaves, and it was aggravated by low S but improved by high S. Concentrations of cysteine and glutathione were increased in Cd-treated leaves, and the Cd-induced increases were limited by low S but stimulated by high S. In line with the physiological changes, a number of mRNAs and microRNAs (miRNAs) involved in Cd accumulation and sulfur assimilation were identified and the miRNAs-mRNAs networks were dissected. In the networks, miR395 and miR399 members were identified as hub miRNAs and their targets were ATP sulfurylase 3 (ATPS3), and phosphate 2 (PHO2) and beta galactosidase 1 (BGAL1), respectively. These results suggest that Cd-induced changes in Cd accumulation and sulfur assimilation are exacerbated by low S but alleviated by high S supply, and that miRNAs-mRNAs regulatory networks play pivotal roles in sulfur-mediated Cd detoxification and accumulation in poplars.
Project description:We report transcriptome profiling from three developing stages of middle internode in sweet sorghum. Sequencing of 6 libraries (two replicates from each stage) each stage yielded approximately 80 million reads.
Project description:Small RNAs (sRNAs) are emerging as important regulators of biological processes in plants. To characterize the small RNA species and expression changes in ‘Anliu’ sweet orange (wild type, WT) and its red-flesh mutant (MT) with lycopene accumulation, we used high-throughput pyrosequencing to identify and quantitatively profile sRNAs. We identified 112 known miRNAs belonging to 64 families from the sweet orange. Comparative analysis revealed that 63 of the 112 known miRNAs exhibited significant expression differences between WT and MT. We also identified 12 novel miRNAs and 9 miRNA candidates from sweet orange; the 12 novel miRNAs are in line with the biogenesis characteristics including the stem-loop structure of the pre-miRNAs and existence of the miRNA*s in the sRNA libraries. Comparative profiling revealed that 10 novel miRNAs and 8 miRNA candidates are differentially expressed between WT and MT. Potential targets of these differentially expressed miRNAs included several important genes that are involved in carotenoid biosynthesis, such as geranylgeranyl pyrophosphate synthase (GGPS) and lycopene β-cyclase (LYCb). Moreover, GO and KEGG annotation revealed that high ranked miRNA-target genes are those implicated in transcription regulation, protein modification and photosynthesis. We proposed that miRNA-target genes are the hot-spots for generating sRNAs. This study provides the first large scale cloning and characterization of citrus miRNAs, which also lays a foundation for unraveling the mechanism of lycopene accumulation in the sweet orange mutant on post-transcription level. Size fractionated small RNAs (16-30 bp) from total RNA extracts was ligated to 5' and 3' adapters, and reverse transcribed. After PCR amplification the sample was subjected to Solexa sequencing. The resultant 35nt sequence data were filtered according to base quality value. The remained sequences were used to trim 5' and 3' adaptors. The clean tags were used for further analysis.