Evaluation of osmotic stress tolerance in transgenic Arabidopsis plants expressing Solanum tuberosum D200 gene

Abstract

Developing efficient stress-tolerant crops through genetic engineering remains one of the major challenges for plant biologists. Approximately 20-40% genes of the known eukaryotic genomes, encode proteins of unknown function which lack currently defined motifs or domains. In a previous study, large-scale yeast functional screening approach in potato was used and 69 genes were reported to have enhanced hyperosmotic stress tolerance of yeast. Twelve out of 69 genes were found to have stress tolerance against multiple stresses. One of those 12 identified genes (StD200) encodes a protein of unknown function. In this study, we evaluated the tolerance against PEGinduced osmotic stress in transgenic Arabidopsis plants expressing putative abiotic stressassociated D200 gene. The D200 plants exhibited higher accumulation of chlorophyll and proline and reduced levels of oxidants compared to the wild-type (WT) control plants when subjected to PEG-induced osmotic stress conditions. Our quantitative Real-Time PCR results also suggested an increased accumulation of mRNA transcripts of genes encoding three major antioxidant enzymes in PEG-treated D200 plants compared to WT. Furthermore, improved photosynthetic parameters, F v / F m and performance index in PEG-treated D200 plants indicated that potato D200 gene is a potential candidate gene for developing stress-tolerant crops in future.

Chlorophyll-a Fluorescence Analysis Reveals Differential Response of Photosynthetic Machinery in Melatonin-Treated Oat Plants Exposed to Osmotic Stress

“…Similar findings have been reported earlier in response to different stresses in Arabidopsis [41,42], Nicotiana benthamiana [43], and Avena sativa [10]. APX, SOD, and CAT genes encoding major antioxidant enzymes were seen to be upregulated in the MPEG plants compared to the PEG plants ( Figure 3F-H), concurring with the findings of the previous studies [44,45]. Recent findings have demonstrated that melatonin application improves photosynthesis, induces efficient antioxidant enzyme activity, and upregulates the expression of the related genes encoding APX, SOD, and CAT in response to cold stress, in wheat [7,32] and barley [46] and cadmium toxicity in wheat [47].…”

Salt-Induced Damage is Alleviated by Short-Term Pre-Cold Treatment in Bermudagrass (Cynodon dactylon)

“…The performance indexes of bermudagrass were significantly decreased under salt stress, as shown in this study. A similar result was also reported in Arabidopsis under osmotic stress [61]. Above all, the results suggested that the salt stress negatively affected the electron transfer and energy transduction in PSII of bermudagrass.…”

Melatonin Positively Influences the Photosynthetic Machinery and Antioxidant System of Avena sativa during Salinity Stress

“…The Fv/Fm ratio was markedly higher in Mel+NaCl plants than NaCl plants, further indicating that melatonin had a positive effect in plants exposed to salinity stress ( Figure 4A). The performance index (PI) is an indicator of sample "vitality" and is closely related to plant growth and survival under adverse environmental conditions [50]. The PI was almost 1.6-fold higher in Mel+NaCl plants than in NaCl plants, which reflected the improved growth parameters and overall greener and healthier appearance of the Mel+NaCl plants ( Figure 4B).…”

“…Recent work by Kalaji et al (2018) demonstrated that, although the parameters used in these analyses cannot be used as indicators to distinguish between different stresses, the response of photosystem II to applied stress occurred earlier in drought-stressed plants compared to salinity-stressed plants [48]. Fast fluorescence induction is comprised of four phases: O, the origin, P, the peak, and J-I, the intermediate phases [49,50]. Fast induction kinetics reflect the primary photochemistry of PSII and provide critical information on the reduction of electron acceptors in the electron transport chain (ETC) [2].…”

“…The JIP test converts Chl-a fluorescence data to biophysical parameters that quantify the energy flow through PSII [27,53,54]. In addition to evaluating the damage to the acceptor side of PSII, OJIP analysis also calculates the crucial parameters ABS, TR, ET, and RE [27,50]. Energy fluxes per RC is a specific functional parameter, while the energy fluxes per excited cross section (CS) indicates the corresponding phenomenological energy fluxes.…”