Identification and transcriptomic profiling of genes involved in increasing sugar content during salt stress in sweet sorghum leaves

Abstract

BackgroundSweet sorghum is an annual C4 crop considered to be one of the most promising bio-energy crops due to its high sugar content in stem, yet it is poorly understood how this plant increases its sugar content in response to salt stress. In response to high NaCl, many of its major processes, such as photosynthesis, protein synthesis, energy and lipid metabolism, are inhibited. Interestingly, sugar content in sweet sorghum stems remains constant or even increases in several salt-tolerant species.ResultsIn this study, the transcript profiles of two sweet sorghum inbred lines (salt-tolerant M-81E and salt-sensitive Roma) were analyzed in the presence of 0 mM or 150 mM NaCl in order to elucidate the molecular mechanisms that lead to higher sugar content during salt stress. We identified 864 and 930 differentially expressed genes between control plants and those subjected to salt stress in both M-81E and Roma strains. We determined that the majority of these genes are involved in photosynthesis, carbon fixation, and starch and sucrose metabolism. Genes important for maintaining photosystem structure and for regulating electron transport were less affected by salt stress in the M-81E line compared to the salt-sensitive Roma line. In addition, expression of genes encoding NADP+-malate enzyme and sucrose synthetase was up-regulated and expression of genes encoding invertase was down-regulated under salt stress in M-81E. In contrast, the expression of these genes showed the opposite trend in Roma under salt stress.ConclusionsThe results we obtained revealed that the salt-tolerant genotype M-81E leads to increased sugar content under salt stress by protecting important structures of photosystems, by enhancing the accumulation of photosynthetic products, by increasing the production of sucrose synthetase and by inhibiting sucrose decomposition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1760-5) contains supplementary material, which is available to authorized users.

Comparative Transcriptome Analysis Reveals New lncRNAs Responding to Salt Stress in Sweet Sorghum

“…On the basis of one of our previous studies (Sui et al, 2015), we selected the salt-tolerant sweet sorghum line M-81E and salt-sensitive line Roma as the experimental materials for the RNA-seq analysis. The two sweet sorghum lines were cultured at 28 ± 3 • C (day/night) with 15-h photoperiod (light intensity of 600 µmol m −2 s −1 ) and 70% relative humidity as described by Yang et al (2018).…”

“…The two sweet sorghum lines were cultured at 28 ± 3 • C (day/night) with 15-h photoperiod (light intensity of 600 µmol m −2 s −1 ) and 70% relative humidity as described by Yang et al (2018). An earlier investigation proved that 150 mM NaCl is an appropriate concentration for detecting significant differences in physiological parameters between M-81E and Roma (Sui et al, 2015). Therefore, starting at the three-leaf stage, the plants were treated with nutrient solutions containing 0 or 150 mM NaCl.…”

Lodging markedly reduced the biomass of sweet sorghum via decreasing photosynthesis in saline-alkali field

“…Stalk sugar content is an important indicator of sweet sorghum use as bioenergy feedstock, with the growth progresses, large amounts of sugars accumulated in sweet sorghum stalks, especially in saline-alkali habitats [21]. But the sugar content in sweet sorghum stalks significantly reduced when lodging occurred for 7 days (Fig.…”

Quantitative iTRAQ Proteomics Revealed Possible Roles for Antioxidant Proteins in Sorghum Aluminum Tolerance

“…Sorghum also possesses an extraordinary ability to cope with abiotic stresses. In recent years, the sorghum transcriptome networks have been analyzed to reveal the molecular basis underlying sorghum tolerance to different abiotic stresses (Dugas et al, 2011; Sui et al, 2015). However, the adaptive mechanisms underlying sorghum Al tolerance at the proteomic level are still unclear.…”