A Cytoplasmic Receptor-like Kinase Contributes to Salinity Tolerance

Abstract

Receptor-like cytoplasmic kinases (RLCKs) are receptor kinases that lack extracellular ligand-binding domains and have emerged as a major class of signaling proteins that regulate plant cellular activities in response to biotic/abiotic stresses and endogenous extracellular signaling molecules. We have identified a rice RLCK (OsRLCK311) that was significantly higher in transgenic pSARK-IPT rice (Oryza sativa) that exhibited enhanced growth under saline conditions. Overexpression of OsRLCK311 full-length protein (RLCK311FL) and the C-terminus of OsRLCK311 (ΔN) in Arabidopsis confirmed its role in salinity tolerance, both in seedlings and mature plants. Protein interaction assays indicated that OsRLCK311 and ΔN interacted in-vivo with the plasma membrane AQP AtPIP2;1. The RLCK311-PIP2;1 binding led to alterations in the stomata response to ABA, which was characterized by more open stomata of transgenic plants. Moreover, OsRLCK311-ΔN effect in mediating enhanced plant growth under saline conditions was also observed in the perennial grass Brachypodium sylvaticum, confirming its role in both dicots and monocots species. Lastly, OsRLCK311 interacted with the rice OsPIP2;1. We suggest that the rice OsRLCK311 play a role in regulating the plant growth response under saline conditions via the regulation of the stomata response to stress. This role seems to be independent of the RLCK311 kinase activity, since the overexpression of the RLCK311 C-terminus (ΔN), which lacks the kinase full domain, has a similar phenotype to RLCK311FL.

Adaptable and Multifunctional Ion-Conducting Aquaporins

“…Regulation of PIP2 aquaporins. PIP2 regulation includes transcript regulation (37,239), PTMs (45,153,170,174), PPIs (15,35,152,169,186), and selective endocytosis from the plasma membrane stimulated by reactive oxygen species (127,219). The PTMs and PPIs can affect membrane targeting, substrate selectivity, and pH o sensitivity (71,109,140,158,198,202,222).…”

Analysis of aquaporins in northern grasses reveal functional importance of Puccinellia nuttalliana PIP2;2 in salt tolerance

“…In Arabidopsis, TIP1;1 was re-localised into intravacuolar invaginations under salt stress (Boursiac et al, 2005). An increase in the tissue protein levels of PIPs and TIPs was also reported for salt-acclimated sunflower (Helianthus annus) (Kumari & Bhatla, 2021) and a receptorlike cytoplasmic kinase from rice (OsRLCK311) was found to interact in Arabidopsis with AtPIP2;1 and OsPIP2;1 and induce salt tolerance (Sade et al, 2020). PIP1;3 was reported as a hypoxia-responsive gene (Zwiazek et al, 2017), but the response to salinity stress was unknown.…”

“…In the present study, we were then interested in PIP2;1, PIP2;2, PIP2;3, PIP1;1, PIP1;3, and TIP1;1 as the potential aquaporins that could be involved in plant responses to NaCl. The enhancement of aquaporin‐mediated cell‐to‐cell water transport by NaCl in P. nuttalliana (Vaziriyeganeh et al, 2018, 2022) and improved salt tolerance of Arabidopsis plants overexpressing the halophytic plant aquaporin (Sade et al, 2020) suggest that some of the aquaporins in halophytic plants may have unique properties that enable them to function under salt stress conditions. Therefore, in the present study, we cloned several PIP and TIP aquaporin genes from three related grasses varying in salt tolerance, including a halophytic grass P. nuttalliana , a moderately salt‐tolerant Poa juncifolia , and a relatively salt‐sensitive Poa pratensis (Vaziriyeganeh et al, 2018).…”

Regulation of plant responses to biotic and abiotic stress by receptor-like cytoplasmic kinases

“…In the case of rice, for instance, 86 of the 376 rice RLCK genes were differentially expressed in response to cold, salt, and dehydration stimuli (Vij et al, 2008). OsRLCK311 has been reported to play a positive role in salt tolerance (Sade et al, 2020;Zhang et al, 2021). OsRLCK241 was transcriptionally induced by salt and drought.…”