Transcription factors (TF) are a wide class of genes in plants, and these can regulate the expression of other genes in response to various environmental stresses (biotic and abiotic). In the current study, transcription factor activity in sugarcane was examined during cold stress. Initially, RNA transcript reads of two sugarcane cultivars (ROC22 and GT08-1108) under cold stress were downloaded from SRA NCBI database. The reads were aligned into a reference genome and the differential expression analyses were performed with the R/Bioconductor edgeR package. Based on our analyses in the ROC22 cultivar, 963 TF genes were significantly upregulated under cold stress among a total of 5649 upregulated genes, while 293 TF genes were downregulated among a total of 3,289 downregulated genes. In the GT08-1108 cultivar, 974 TF genes were identified among 5,649 upregulated genes and 283 TF genes were found among 3,289 downregulated genes. Most transcription factors were annotated with GO categories related to protein binding, transcription factor binding, DNA-sequence-specific binding, transcription factor complex, transcription factor activity in RNA polymerase II, the activity of nucleic acid binding transcription factor, transcription corepressor activity, sequence-specific regulatory region, the activity of transcription factor of RNA polymerase II, transcription factor cofactor activity, transcription factor activity from plastid promoter, transcription factor activity from RNA polymerase I promoter, polymerase II and RNA polymerase III. The findings of above results will help to identify differentially expressed transcription factors during cold stress. It also provides a comprehensive analysis of the regulation of the transcription activity of many genes. Therefore, this study provides the molecular basis for improving cold tolerance in sugarcane and other economically important grasses.

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The genus Psilotum belongs to Psilotaceae family, with about 133 to 189 species having outstanding social, economic and medically important relict plants. However, being living fossil plant, many hurdles come in way while trying to discern its phylogenetics reconstruction. The partial conserve nucleotide sequences of rbcLa, trnA, trnV, matK, ITS, ycF3 and rpoB genes were used to select the best suitable barcodes in Psilotum nudum L. The amplified fragments were subjected to Sanger sequencing and then Maximum likelihood, Maximum Parsimony and Neighbor Joining trees were generated using bioinformatics software. i.e., MUSCLE, BioEdit and Mega-7. Current population showed the best match between P. complanatum (KY099851.1), population reported from New Zealand and P. nudum (F384430.1) with identity value 100 and 99% having E-value 0.0 and 0.0 by rbcLa and trnA barcode region, respectively. The findings showed that P. nudum L. sequences are ever first reported from the Himalaya regions of Pakistan and could be utilized for further comparison among different populations of this relict plant species across the globe.

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Transcriptomic data of two sugarcane cultivars ‘ROC22’ and ‘GT08-1108’ were investigated for the expression analysis of cold responsive genes. The raw RNA Seq data of the sugarcane cultivars were downloaded from the SRA NCBI database and were reanalyzed and mapped by using Saccharum spontaneum genome.  In the Saccharum spontaneum reference genome, 83826 unigenes were annotated and, among these, 46,159 (55%) were functionally annotated with Gene Ontology (GO) categories. In the transcriptome-based analysis, 183,515 unigenes were assembled and, among these, 110,021 (60%) were functionally annotated with GO categories. For the cultivar GT08-1108, using the reference genome pipeline, 11,652 (13.9%) unigenes were differentially expressed (7,238 upregulated; 4,414 downregulated), while 16,145 (8.8%) were differentially expressed (8,965 upregulated; 7,180 downregulated) using transcriptome-based pipeline. In the cultivar ROC22, 11,516 (13.7%) genes were differentially expressed (7,174 upregulated; 4,342 downregulated) and 20,317 (11.1%) (10,898 upregulated; 9,419 downregulated) for the genome and transcriptome-based analysis, respectively. In the genome analyses, among downregulated genes, 3,248 were coincident between the two cultivars, the remaining 1,166 differentially expressed only in ‘GT-1180’ and 1,094 only in ‘ROC22’. With the transcriptome assembly, 13,113 genes were deferentially expressed in both cultivars, the remaining 3,032 unique to ‘GT08-1108’ and 7,204 in ‘ROC22’. We concluded that sugarcane in response to cold stress expresses many genes, although the transcriptome assembly overestimated the number of unigenes and, consequently, a higher number of differentially expressed genes. This may be due to difficulties in separating homeologues from paralogue genes. When a reference genome is available, we recommend its use since genes predicted on a reference genome tend to be more accurate.