Overexpression of A Biotic Stress-Inducible Pvgstu Gene Activates Early Protective Responses in Tobacco under Combined Heat and Drought.

Evangelia Stavridou,Evangelia G Chronopoulou,Nikolaos E Labrou,Panagiotis Madesis,Michail Michailidis,Georgia Voulgari,Irini Nianiou-Obeidat,Stefanos Kostas

doi:10.3390/ijms22052352

Abstract

Drought and heat stresses are major factors limiting crop growth and productivity, and their effect is more devastating when occurring concurrently. Plant glutathione transferases (GSTs) are differentially expressed in response to different stimuli, conferring tolerance to a wide range of abiotic stresses. GSTs from drought-tolerant Phaseolus vulgaris var. “Plake Megalosperma Prespon” is expected to play an important role in the response mechanisms to combined and single heat and drought stresses. Herein, we examined wild-type N. tabacum plants (cv. Basmas Xanthi) and T1 transgenic lines overexpressing the stress-induced Pvgstu3–3 and Pvgstu2–2 genes. The overexpression of Pvgstu3–3 contributed to potential thermotolerance and greater plant performance under combined stress. Significant alterations in the primary metabolism were observed in the transgenic plants between combined stress and stress-free conditions. Stress-responsive differentially expressed genes (DEGs) and transcription factors (TFs) related to photosynthesis, signal transduction, starch and sucrose metabolism, osmotic adjustment and thermotolerance, were identified under combined stress. In contrast, induction of certain DEGs and TF families under stress-free conditions indicated that transgenic plants were in a primed state. The overexpression of the Pvgstu3–3 is playing a leading role in the production of signaling molecules, induction of specific metabolites and activation of the protective mechanisms for enhanced protection against combined abiotic stresses in tobacco.

Highlights

Drought and high temperature are two of the most severe environmental factors as they usually occur concurrently, causing a reduction in crop growth and productivity worldwide [1,2], and their combined effect is greater than when occurring individually [3]
The recombinant plasmids were transferred to E. coli, and the colonies were screened for successful insertion of the plasmid (Figure S1b,c) (More details can be found in the supplementary material)
RT–PCR analysis verified that 19 out of 21 putative transgenic lines were positive for the Pvgstu2–2 (~90.5% success) and 9 out of 10 (~90% success) for the Pvgstu3–3

Summary

Introduction

Drought and high temperature are two of the most severe environmental factors as they usually occur concurrently, causing a reduction in crop growth and productivity worldwide [1,2], and their combined effect is greater than when occurring individually [3]. Identifying distinctive or common mechanisms necessary for plant acclimatization and tolerance under combined abiotic stresses is a prerequisite for mitigating the negative effects of climate change. Much remains to be discovered about the underlying mechanisms of systemic plant response to combinations of stress [10,11,12]. In such an endeavor, an integrated systems biology approach would potentially shed light on the gene function towards a better understanding of the abiotic stress response mechanisms for developing climatechange-oriented breeding strategies

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Conclusion