An official website of the United States government
Potassium (K) is an essential macronutrient for plant growth, and its availability in the soil varies widely, requiring plants to respond and adapt to the changing K nutrient status. We show here that plant growth rate is closely correlated with K status in the medium, and this K-dependent growth is mediated by the highly conserved nutrient sensor, target of rapamycin (TOR). Further study connected the TOR complex (TORC) pathway with a low-K response signaling network consisting of calcineurin B-like proteins (CBL) and CBL-interacting kinases (CIPK). Under high K conditions, TORC is rapidly activated and shut down the CBL–CIPK low-K response pathway through regulatory-associated protein of TOR (RAPTOR)–CIPK interaction. In contrast, low-K status activates CBL–CIPK modules that in turn inhibit TORC by phosphorylating RAPTOR, leading to dissociation and thus inactivation of the TORC. The reciprocal regulation of the TORC and CBL–CIPK modules orchestrates plant response and adaptation to K nutrient status in the environment.
more »
« less
This content will become publicly available on July 1, 2026
A calcium sensor kinase pathway interacts with the TOR complex to balance growth and salt tolerance in Arabidopsis
Abstract Soil salinity negatively affects crop yields worldwide. The dynamic transition between growth and salt stress responses helps plants cope with changing soil salinity status. However, the molecular mechanisms controlling such dynamic transitions remain poorly understood. Here, our study identified the target of rapamycin complex (TORC) as a central player in growth recovery from salt stress. We observed a rapid decline in TORC activity in Arabidopsis thaliana plants upon exposure to salt stress. Further investigation uncovered an intricate interplay between TORC and a salt response signaling network comprising calcineurin B-like (CBL) proteins and CBL-interacting kinases (CIPKs). Under standard growth conditions, Regulatory-Associated Protein of TOR (RAPTOR) promotes CBL–CIPK complex dissociation, thereby inhibiting CIPK. CIPK suppression is lifted under salt stress, and the activated CBL–CIPK complex phosphorylates RAPTOR, which in turn suppresses TORC activity. Thus, the reciprocal regulation of the TORC and CBL–CIPK modules orchestrates plant responses and adaptation to soil salinity.
more »
« less
- Award ID(s):
- 2344945
- PAR ID:
- 10648634
- Publisher / Repository:
- Oxford journals
- Date Published:
- Journal Name:
- The Plant Cell
- Volume:
- 37
- Issue:
- 7
- ISSN:
- 1040-4651
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Background Plant growth promoting rhizobacteria (PGPR) , such as Bradyrhizobium japonicum IRAT FA3, are able to improve seed germination and plant growth under various biotic and abiotic stress conditions, including high salinity stress. PGPR can affect plants’ responses to stress via multiple pathways which are often interconnected but were previously thought to be distinct. Although the overall impacts of PGPR on plant growth and stress tolerance have been well documented, the underlying mechanisms are not fully elucidated. This work contributes to understanding how PGPR promote abiotic stress by revealing major plant pathways triggered by B. japonicum under salt stress. Results The plant growth-promoting rhizobacterial (PGPR) strain Bradyrhizobium japonicum IRAT FA3 reduced the levels of sodium in Arabidopsis thaliana by 37.7% . B. japonicum primed plants as it stimulated an increase in jasmonates (JA) and modulated hydrogen peroxide production shortly after inoculation. B. japonicum -primed plants displayed enhanced shoot biomass, reduced lipid peroxidation and limited sodium accumulation under salt stress conditions. Q(RT)-PCR analysis of JA and abiotic stress-related gene expression in Arabidopsis plants pretreated with B. japonicum and followed by six hours of salt stress revealed differential gene expression compared to non-inoculated plants. Response to Desiccation ( RD ) gene RD20 and reactive oxygen species scavenging genes CAT3 and MDAR2 were up-regulated in shoots while CAT3 and RD22 were increased in roots by B. japonicum , suggesting roles for these genes in B. japonicum -mediated salt tolerance. B. japonicum also influenced reductions of RD22 , MSD1 , DHAR and MYC2 in shoots and DHAR , ADC2 , RD20 , RD29B , GTR1 , ANAC055 , VSP1 and VSP2 gene expression in roots under salt stress. Conclusion Our data showed that MYC2 and JAR1 are required for B. japonicum -induced shoot growth in both salt stressed and non-stressed plants. The observed microbially influenced reactions to salinity stress in inoculated plants underscore the complexity of the B. japonicum jasmonic acid-mediated plant response salt tolerance.more » « less
-
Salinity stress threatens soil microbiomes, a key driver of soil multifunctionality and health. This study employed high-throughput sequencing of 16S rRNA, PLFAs, multifunctionality index, and co-occurrence networks to gain a comprehensive understanding of the dynamic responses of soil microbiomes to salinity stress gradient (0, 0.4 and 1 mol NaCl). Additionally, we investigated how these responses are shaped by the addition of vermicompost and NPK fertilizer during short-term (2-h) and long-term (70-day) incubation periods. Salinity stress reduced bacterial and fungal phospholipid fatty acids (PLFA) concentrations in the short-term. Over the long-term, the microbial community evolved into a new pattern under salt stress, favoring the presence ofBacteriodota, a salt-tolerant phylum, while decreasing the relative abundance ofAcidobacteriotaandPlanctomycetota, which are more salt-sensitive. Furthermore, salinity decreased species richness by 11.33% and soil multifunctionality by 21.48% but increased microbial network complexity while decreasing its stability. Incorporating vermicompost increased bacterial and fungal PLFAs, enhanced bacterial diversity by 2.33%, promoted salt-tolerant bacteria, and increased the complexity and stability of the bacterial network. Conversely, the application of NPK fertilizer reduced bacterial richness, alpha diversity and soil multifunctionality by 14.52, 5.83, and 12.34%, respectively, further disrupting the microbial community and making resilience to salinity stress more challenging. Furthermore, NPK fertilization increased bacterial network complexity but decreased its stability. This study underscores the significance of employing vermicompost to improve the health of saline soils. Furthermore, it emphasizes the negative impacts of NPK fertilizer on soil microbial structure and function and hinder its recovery from salinity’s impacts.more » « less
-
Brassinosteroids (BR) and Target of Rapamycin Complex (TORC) are two major actors coordinating plant growth and stress responses. BRs function through a signaling pathway to extensively regulate gene expression and TORC is known to regulate translation and autophagy. Recent studies have revealed connections between these two pathways, but a system-wide view of their interplay is still missing. • We quantified the level of 23,975 transcripts, 11,183 proteins, and 27,887phosphorylation sites in wild-type Arabidopsis thalianaand inmutants with altered levels of either BRASSINOSTEROID INSENSITIVE 2 (B IN2) or REGULATORY ASSOCIATED PROTEIN OF TOR 1B (RAPTOR1B), two key players in BR and TORC signaling, respectively.• We found that perturbation of BIN2 or RAPTOR1B levels affects a common set of gene-products involved in growth and stress responses. Furthermore, we used the multi-omic data to reconstruct an integrated signaling network. We screened 41candidate genes identified from the reconstructed network and found that loss of function mutants of many of these proteins led to an altered BR response and/or modulated autophagy activity.• Altogether, these results establish a predictive network that defines different layers of molecular interactions between BR- or TORC-regulated growth and autophagy.more » « less
-
In a search for efficient fungal endophytes that can promote crop production and/or increase crop tolerance to abiotic stress, we isolated and tested various species harbored by wild plants. Sixty-seven endophytic fungal isolates were obtained from drought stressed, poor soil habitats, and inland high salt areas. We extensively tested the roles of Ampelomyces sp. and Penicillium sp. isolates in improving tomato growth and yield. Under greenhouse and field trails, Ampelomyces sp. and Penicillium sp. endophytes proved effective in conferring positive benefits to tomatoes placed under stress as well as under normal growing conditions. Ampelomyces sp. conferred tolerance to tomatoes placed under drought stress in addition to enhancing overall plant growth and fruit yield in comparison to non-symbiotic plants under drought stress. Penicillium sp. conferred tolerance to tomatoes placed under 300 mM salinity stress in addition to enhancing root biomass in comparison to non-symbiotic plants. Both endophytes proved efficient in enhancing plant growth, stress tolerance, recovery, and fruit yield under optimal experimental conditions in comparison to non-symbiotic plants. Field testing of tomato yield showed increased yield of symbiotic tomatoes compared to non-symbiotic ones. This data suggests that both Ampelomyces sp. and Penicillium sp. share a promising potential for improving future agricultural production, particularly with the projected changes in climate in the future.more » « less
