Ectopic expression of phloem motor protein pea forisome PsSEO-F1 enhances salinity stress tolerance in tobacco

Abstract

PsSEOF-1 binds to calcium and its expression is upregulated by salinity treatment. PsSEOF - 1 -overexpressing transgenic tobacco showed enhanced salinity stress tolerance by maintaining cellular ion homeostasis and modulating ROS-scavenging pathway. Calcium (Ca(2+)) plays important role in growth, development and stress tolerance in plants. Cellular Ca(2+) homeostasis is achieved by the collective action of channels, pumps, antiporters and by Ca(2+) chelators present in the cell like calcium-binding proteins. Forisomes are ATP-independent mechanically active motor proteins known to function in wound sealing of injured sieve elements of phloem tissue. The Ca(2+)-binding activity of forisome and its role in abiotic stress signaling were largely unknown. Here we report the Ca(2+)-binding activity of pea forisome (PsSEO-F1) and its novel function in promoting salinity tolerance in transgenic tobacco. Native PsSEO-F1 promoter positively responded in salinity stress as confirmed using GUS reporter. Overexpression of PsSEO-F1 tobacco plants confers salinity tolerance by alleviating ionic toxicity and increased ROS scavenging activity which probably results in reduced membrane damage and improved yield under salinity stress. Evaluation of several physiological indices shows an increase in relative water content, electrolyte leakage, proline accumulation and chlorophyll content in transgenic lines as compared with null-segregant control. Expression of several genes involved in cellular homeostasis is perturbed by PsSEO-F1 overexpression. These findings suggest that PsSEO-F1 provides salinity tolerance through cellular Ca(2+) homeostasis which in turn modulates ROS machinery providing indirect link between Ca(2+) and ROS signaling under salinity-induced perturbation. PsSEO-F1 most likely functions in salinity stress tolerance by improving antioxidant machinery and mitigating ion toxicity in transgenic lines. This finding should make an important contribution in our better understanding of the significance of calcium signaling in phloem tissue leading to salinity stress tolerance.

Functional Evaluation of Proteins in Watery and Gel Saliva of Aphids

“…Remarkably, no known Ca 2+ -binding motifs were found so far in legume SEOs (Tuteja et al, 2010; Srivastava et al, 2016), but the pea forisome protein PsSEO-F1 showed a cleat-cut Ca 2+ -binding capability (Srivastava et al, 2016) so that identification of Ca 2+ binding motifs in SEO protein structures may be a matter of time.…”

CaFtsH06, A Novel Filamentous Thermosensitive Protease Gene, Is Involved in Heat, Salt, and Drought Stress Tolerance of Pepper (Capsicum annuum L.)

“…In addition, we found that the CaFtsH06-silenced peppers had higher leaf REL and proline content when exposed to salt and drought stress (Figures 7E and 8C). Under different stress conditions, the excess accumulation of ROS, such as H 2 O 2 and •O 2 − , likely resulted in membrane damage and damage to other macro molecules, such as proteins, lipids, and the photosynthetic apparatus [48,49]. Therefore, the contents of H 2 O 2 and •O 2 − were also indicators of the damage level to plant cells [50].…”

The CaChiVI2 Gene of Capsicum annuum L. Confers Resistance Against Heat Stress and Infection of Phytophthora capsici

“…They perform multiple roles by acting directly in the initial defense. However, the over-accumulation of H 2 O 2 and O 2 − under stress results in an active damage to the cell structures, photosynthesis and natural intracellular environment (Uzilday et al, 2012;Tuteja et al, 2014;Srivastava et al, 2016; Haq et al, 2019). Therefore, the contents of H 2 O 2 and O 2 − are often used to find the damage levels of plant cells (Li et al, 2018).…”