Cytokinins are involved in the regulation of many plant growth and development processes, and function in response to abiotic stress. Cytokinin signaling is similar to the prokaryotic two-component signaling systems and includes the transcriptional upregulation of type-A response regulators (RRs), which in turn act to inhibit cytokinin signal response via negative feedback. Cytokinin signaling consists of several gene families and only a handful full of genes is studied. In this study, we demonstrated the function of two highly identical type-A RR genes from rice, OsRR9 and OsRR10, which are induced by cytokinin and only OsRR10 repressed by salinity stress in rice. Loss-of-function mutations give rise to mutant genes, osrr9/osrr10, which have higher salinity tolerance than wild type rice seedlings. The transcriptomic analysis uncovered several ion transporter genes, which were upregulated in response to salt stress in the osrr9/osrr10 mutants relative to the wild type seedlings. These include high-affinity potassium transporters, such as OsHKT1;1, OsHKT1;3 and OsHKT2;1, which play an important role in sodium and potassium homeostasis. In addition, disruption of the genes OsRR9 and OsRR10 also affects the expression of multiple genes related to photosynthesis, transcription and phytohormone signaling. Taken together, these results suggest that the genes OsRR9 and OsRR10 function as negative regulators in response to salinity in rice.
- NSF-PAR ID:
- 10151630
- Date Published:
- Journal Name:
- Plants
- Volume:
- 9
- Issue:
- 2
- ISSN:
- 2223-7747
- Page Range / eLocation ID:
- 166
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Structural variation in plant genomes is a significant driver of phenotypic variability in traits important for the domestication and productivity of crop species. Among these are traits that depend on functional meristems, populations of stem cells maintained by the CLAVATA-WUSCHEL (CLV-WUS) negative feedback-loop that controls the expression of the WUS homeobox transcription factor. WUS function and impact on maize development and yield remain largely unexplored. Here we show that the maize dominant
Barren inflorescence3 (Bif3 ) mutant harbors a tandem duplicated copy of theZmWUS1 gene,ZmWUS1-B , whose novel promoter enhances transcription in a ring-like pattern. Overexpression ofZmWUS1-B is due to multimerized binding sites for type-B RESPONSE REGULATORs (RRs), key transcription factors in cytokinin signaling. Hypersensitivity to cytokinin causes stem cell overproliferation and major rearrangements ofBif3 inflorescence meristems, leading to the formation of ball-shaped ears and severely affecting productivity. These findings establishZmWUS1 as an essential meristem size regulator in maize and highlight the striking effect of cis-regulatory variation on a key developmental program. -
Hydrogen sulfide (H2S) serves as an important gaseous signaling molecule that is involved in intra- and intercellular signal transduction in plant–environment interactions. In plants, H2S is formed in sulfate/cysteine reduction pathways. The activation of endogenous H2S and its exogenous application has been found to be highly effective in ameliorating a wide variety of stress conditions in plants. The H2S interferes with the cellular redox regulatory network and prevents the degradation of proteins from oxidative stress via post-translational modifications (PTMs). H2S-mediated persulfidation allows the rapid response of proteins in signaling networks to environmental stimuli. In addition, regulatory crosstalk of H2S with other gaseous signals and plant growth regulators enable the activation of multiple signaling cascades that drive cellular adaptation. In this review, we summarize and discuss the current understanding of the molecular mechanisms of H2S-induced cellular adjustments and the interactions between H2S and various signaling pathways in plants, emphasizing the recent progress in our understanding of the effects of H2S on the PTMs of proteins. We also discuss future directions that would advance our understanding of H2S interactions to ultimately mitigate the impacts of environmental stresses in the plants.more » « less
-
more » « less
SUMMARY The phytohormone cytokinin plays a significant role in nearly all aspects of plant growth and development. Cytokinin signaling has primarily been studied in the dicot model Arabidopsis, with relatively little work done in monocots, which include rice (
Oryza sativa ) and other cereals of agronomic importance. The cytokinin signaling pathway is a phosphorelay comprised of the histidine kinase receptors, the authentic histidine phosphotransfer proteins (AHPs) and type‐B response regulators (RRs). Two negative regulators of cytokinin signaling have been identified: the type‐A RRs, which are cytokinin primary response genes, and the pseudo histidine phosphotransfer proteins (PHPs), which lack the His residue required for phosphorelay. Here, we describe the role of the ricePHP genes. Phylogenic analysis indicates that the PHPs are generally first found in the genomes of gymnosperms and that they arose independently in monocots and dicots. Consistent with this, the three ricePHPs fail to complement an Arabidopsisphp mutant (aphp1/ahp6 ). Disruption of the three ricePHPs results in a molecular phenotype consistent with these elements acting as negative regulators of cytokinin signaling, including the induction of a number of type‐A RR and cytokinin oxidase genes. The triplephp mutant affects multiple aspects of rice growth and development, including shoot morphology, panicle architecture, and seed fill. In contrast to Arabidopsis, disruption of the ricePHPs does not affect root vascular patterning, suggesting that while many aspects of key signaling networks are conserved between monocots and dicots, the roles of at least some cytokinin signaling elements are distinct. -
more » « less
Summary Cytokinins control critical aspects of plant development and environmental responses. Perception of cytokinin ultimately leads to the activation of proteins belonging to the type‐B Response Regulator family of cytokinin response activators. In
Arabidopsis thaliana , ARR1 is one of the most abundantly expressed type‐B Response Regulators.We investigated the link between cytokinin signaling, protein synthesis, plant growth and osmotic stress tolerance.
We show that the increased cytokinin signaling in ARR1 gain‐of‐function transgenic lines is associated with increased rates of protein synthesis, which lead to growth inhibition and hypersensitivity to osmotic stress. Cytokinin‐induced growth inhibition and osmotic stress hypersensitivity were rescued by treatments with ABA, a hormone known to inhibit protein synthesis. We also demonstrate that cytokinin‐induced protein synthesis requires isoforms of the ribosomal protein L4 encoded by the cytokinin‐inducible genes
RPL4A andRPL4D , and thatRPL4 loss‐of‐function increases osmotic stress tolerance and decreases sensitivity to cytokinin‐induced growth inhibition.These findings reveal that an increase in protein synthesis negatively impacts growth and osmotic stress tolerance and explain some of the adverse effects of elevated cytokinin action on plant development and stress physiology.
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/plants9020166
