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:Sorghum is multipurpose crop worldwide serving as food, feed, and feedstock for biofuels, whose floral transition and vegetative growth heavily depend on photoperiod. Although multiple sorghum maturity loci (Ma1-Ma6) have been associated with photoperiod sensitivity in previous QTL studies, the underlying molecular mechanisms remain poorly understood. By functional characterizing sorghum SbGhd7 (Ma6) and integrating RNA-seq analysis of Ghd7 overexpression sorghum, ChIP-seq analysis of SbGhd7 binding sites in protoplasts and molecular studies, we discovered that SbEhd1 and SbFT10 are the direct targets of SbGhd7. SbGhd7 is a transcriptional repressor and inhibits florigen-induced floral transition by repressing SbEhd1 and SbFT10 expression.
Project description:Different plant species within the grasses were parallel targets of domestication, giving rise to crops with distinct evolutionary histories and traits. Key traits that distinguish these species are mediated by specialized cell types. Here, we compare the transcriptomes of root cells in three grass species—Zea mays (maize), Sorghum bicolor (sorghum), and Setaria viridis (Setaria). We first show that single-cell and single-nucleus RNA-seq provide complementary readouts of cell identity in both dicots and monocots, warranting a combined analysis. Cell types were mapped across species to identify robust, orthologous marker genes. The comparative cellular analysis shows that the transcriptomes of some cell types diverged more rapidly than others—driven, in part, by recruitment of gene modules from other cell types. The data also show that a recent whole genome duplication provides a rich source of new, highly localized gene expression domains that favor fast- evolving cell types. Together, the cell-by-cell comparative analysis shows how fine-scale cellular profiling can extract conserved modules from a pan transcriptome and shed light on the evolution of cells that mediate key functions in crops.
Project description:Nitrogen is essential for plant growth and development. Improving the ability of plants to acquire and assimilate nitrogen more efficiently is a key agronomic parameter that will augment sustainability in agriculture. A transcription factor approach was pursued to address improvement of nitrogen use efficiency in two major commodity crops. To this end, the Zea mays Dof1 (ZmDof1) transcription factor was expressed in both wheat (Triticum aestivum) and sorghum (Sorghum bicolor) either constitutively, UBI4 promoter from sugarcane, or in a tissue specific fashion via the maize rbcS1 promoter. The primary transcription activation target of ZmDof1, phosphoenolpyruvate carboxylase (PEPC), is observed in transgenic wheat events. Expression ZmDof1 under control of the rbcs1 promoter translates to increase in biomass and yield components in wheat. However, constitutive expression of ZmDof1 led to the down-regulation of genes involved in photosynthesis and the functional apparatus of chloroplasts, and an outcome that negatively impacts photosynthesis, height, and biomass in wheat. Similar patterns were also observed in sorghum transgenic events harboring the constitutive expression cassette of ZmDof1. These results indicate that transcription factor strategies to boost agronomic phenotypic outcomes in crops need to consider expression patterns of the genetic elements to be introduced.
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:Sorghum is multipurpose crop worldwide serving as food, feed, and feedstock for biofuels, whose floral transition and vegetative growth heavily depend on photoperiod. Although multiple sorghum maturity loci (Ma1-Ma6) have been associated with photoperiod sensitivity in previous QTL studies, the underlying molecular mechanisms remain poorly understood. By functional characterizing sorghum SbGhd7 (Ma6) and integrating RNA-seq analysis of Ghd7 overexpression sorghum, ChIP-seq analysis of SbGhd7 binding sites in protoplasts and molecular studies, we discovered that SbEhd1 and SbFT10 are the direct targets of SbGhd7. SbGhd7 is a transcriptional repressor and inhibits florigen-induced floral transition by repressing SbEhd1 and SbFT10 expression.
Project description:Sugarcane aphids (SCA; Melanaphis sacchari Zehntner) is a key piercing-sucking type pest of sorghum (Sorghum bicolor) which cause significant yield losses. While feeding on host plants, complex signaling networks are invoked from recognition of insect attack to induction of plant defenses. Consequently, these signaling networks lead to the production of insecticidal compounds or limited access to nutrients to insects. Previously, several studies are published on the transcriptomics analysis of sorghum in response to SCA infestation, but no information is available on the physiological changes of sorghum at proteome level. We used SCA resistant sorghum genotype SC265 for the global proteomics analysis after 1 and 7 days of SCA infestation using TMT-plex technique.
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.