Transgenic sugarcane overexpressing Glyoxalase III improved germination and biomass production at formative stage under salinity and water-deficit stress conditions.

The glyoxalase system, involving Glyoxalase I (GlyI) and Glyoxalase II (Gly II), plays a vital role in abiotic stress tolerance in plants. A novel enzyme Glyoxalase III (Gly III) was found recently from bacteria, yeast, and plant species. This enzyme provides a new way to detoxify Methylglyoxal (MG), a cytotoxic α-oxoaldehyde, which, in excess, can cause complete cell destruction by forming Reactive Oxygen Species (ROS) and Advanced Glycation End products (AGEs) or DNA/RNA mutation. In this background, the current study examined sugarcane transgenic events that exhibit an increase in expression of EaGly III, to assess their performance in terms of germination and biomass production during formative stage under stress conditions. Southern blot analysis outcomes confirmed the integration of transgene in the transgenic plants. The results from quantitative RT-PCR analyses confirmed high expression levels of EaGly III in transgenic events compared to wild type (WT) under salinity (100 and 200 mM NaCl) and drought (withholding watering) conditions. Transgenic events exhibited enhanced biomass productivity ranged between 0.141 Kg/pot and 0.395 Kg/pot under 200 mM salinity and 0.262 Kg/pot and 0.666 Kg/pot under drought stress. Further, transgenic events observed significantly higher germination rates under salinity and drought conditions compared to that of WT. Subcellular localization prediction by EaGlyIII-GFP fusion expression in sugarcane callus showed that it is distributed across the cytoplasm, thus indicating its widespread activity within the cell. These results strongly suggest that enhancing EaGly III activity is a useful strategy to improve the salinity and drought-tolerance in sugarcane as well as other crops.

High-throughput sequencing reveals genes associated with high-temperature stress tolerance in sugarcane.

Sugarcane (Saccharum spp.) is a major sugar crop grown in tropical and sub-tropical areas throughout the world which is vulnerable to high temperature stress due to climate change. In this present study, we have generated a transcriptome profile of sugarcane variety Co 99004 exposed to high-temperature stress (47 °C). The Illumina Nexseq2500 platform yielded a total of 39.28 and 13.44 million reads, corresponding to 3.9 and 1.3 gigabase pair (Gb) of the processed reads for control and high-temperature-stressed samples, respectively. Initially, the reads were de novo assembled into 118,017 unigenes with an average length of 780 bp. The longest sequence in the assembly was 21 kb. Further, these transcripts were BLASTed against GO, KEGG and COG databases to identify the novel genes/transcripts expressed due to elevated temperature conditions. The different expression analysis showed 1137 transcripts which were up-regulated during heat temperature stress when compared to control conditions. Analysis of relative gene expression showed phytepsin, ferredoxin-dependent glutamate synthase, and stress protein DDR-48 threefold increased expression during heat stress. These findings reveal novel targets for subsequent research on the genomics genetic manipulation and molecular mechanism of elevated stress tolerance in sugarcane.