AUTHOR=Ramasamy Manikandan , Damaj Mona B. , Vargas-Bautista Carol , Mora Victoria , Liu Jiaxing , Padilla Carmen S. , Irigoyen Sonia , Saini Tripti , Sahoo Nirakar , DaSilva Jorge A. , Mandadi Kranthi K. 

TITLE=A Sugarcane G-Protein-Coupled Receptor, ShGPCR1, Confers Tolerance to Multiple Abiotic Stresses

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.745891

DOI=10.3389/fpls.2021.745891

ISSN=1664-462X

ABSTRACT=<p>Sugarcane (<italic>Saccharum</italic> spp.) is a prominent source of sugar and serves as bioenergy/biomass feedstock globally. Multiple biotic and abiotic stresses, including drought, salinity, and cold, adversely affect sugarcane yield. G-protein-coupled receptors (GPCRs) are components of G-protein-mediated signaling affecting plant growth, development, and stress responses. Here, we identified a GPCR-like protein (<italic>ShGPCR1</italic>) from sugarcane and energy cane (<italic>Saccharum</italic> spp. hybrids) and characterized its function in conferring tolerance to multiple abiotic stresses. <italic>ShGPCR1</italic> protein sequence contained nine predicted transmembrane (TM) domains connected by four extracellular and four intracellular loops, which could interact with various ligands and heterotrimeric G proteins in the cells. <italic>ShGPCR1</italic> sequence displayed other signature features of a GPCR, such as a putative guanidine triphosphate (GTP)-binding domain, as well as multiple myristoylation and protein phosphorylation sites, presumably important for its biochemical function. Expression of <italic>ShGPCR1</italic> was upregulated by drought, salinity, and cold stresses. Subcellular imaging and calcium (Ca<sup>2+</sup>) measurements revealed that <italic>ShGPCR1</italic> predominantly localized to the plasma membrane and enhanced intracellular Ca<sup>2+</sup> levels in response to GTP, respectively. Furthermore, constitutive overexpression of <italic>ShGPCR1</italic> in sugarcane conferred tolerance to the three stressors. The stress-tolerance phenotype of the transgenic lines corresponded with activation of multiple drought-, salinity-, and cold-stress marker genes, such as <italic>Saccharum</italic> spp. <italic>LATE EMBRYOGENESIS ABUNDANT</italic>, <italic>DEHYDRIN</italic>, <italic>DROUGHT RESPONSIVE 4</italic>, <italic>GALACTINOL SYNTHASE, ETHYLENE RESPONSIVE FACTOR 3</italic>, <italic>SALT OVERLY SENSITIVE 1</italic>, <italic>VACUOLAR Na+/H+ ANTIPORTER 1</italic>, <italic>NAM</italic>/<italic>ATAF1/2</italic>/<italic>CUC2</italic>, <italic>COLD RESPONSIVE FACTOR</italic> 2, and <italic>ALCOHOL DEHYDROGENASE 3</italic>. We suggest that <italic>ShGPCR1</italic> plays a key role in conferring tolerance to multiple abiotic stresses, and the engineered lines may be useful to enhance sugarcane production in marginal environments with fewer resources.</p>