Precursor processing by SBT3.8 and phytosulfokine signaling contribute to drought stress tolerance in Arabidopsis

Author(s):  
Nils Stührwohldt ◽  
Eric Bühler ◽  
Margret Sauter ◽  
Andreas Schaller

Abstract Increasing drought stress poses a severe threat to agricultural productivity. Plants, however, evolved numerous mechanisms to cope with such environmental stress. Here we report that the stress-induced production of a peptide signal contributes to stress tolerance. The expression of phytosulfokine (PSK) peptide precursor genes, and transcripts of three subtilisin-like serine proteases, SBT1.4, SBT3.7 and SBT3.8 were found to be up-regulated in response to osmotic stress. Stress symptoms were enhanced in sbt3.8 loss-of-function mutants and could be alleviated by PSK treatment. Osmotic stress tolerance was improved in plants overexpressing the precursor of PSK1 (proPSK1) or SBT3.8 resulting in higher fresh weight and improved lateral root development in the transgenic compared to wild-type plants. We further showed that SBT3.8 is involved in the biogenesis of the bioactive PSK peptide. ProPSK1 was cleaved by SBT3.8 at the C-terminus of the PSK pentapeptide. Processing by SBT3.8 depended on the aspartic acid residue directly following the cleavage site. ProPSK1 processing was impaired in the sbt3.8 mutant. The data suggest that increased expression in response to osmotic stress followed by the post-translational processing of proPSK1 by SBT3.8 leads to the production of PSK as a peptide signal for stress mitigation.

2020 ◽  
Author(s):  
Nils Stührwohldt ◽  
Eric Bühler ◽  
Margret Sauter ◽  
Andreas Schaller

AbstractIncreasing drought stress poses a severe threat to agricultural productivity. Plants, however, evolved numerous mechanisms to cope with such environmental stress. Here we report that the stress-induced production of a peptide signal contributes to stress tolerance. The expression of phytosulfokine (PSK) peptide precursor genes, and transcripts of three subtilisin-like serine proteases, SBT1.4, SBT3.7 and SBT3.8 were found to be up-regulated in response to osmotic stress. Stress symptoms were enhanced in sbt3.8 loss-of-function mutants and could be alleviated by PSK treatment. Osmotic stress tolerance was improved in plants overexpression the precursor of PSK1 (proPSK1) or SBT3.8 resulting in higher fresh weight and improved lateral root development in the transgenic compared to wild-type plants. We further showed that SBT3.8 is involved in the biogenesis of the bioactive PSK peptide. ProPSK1 was cleaved by SBT3.8 at the C-terminus of the PSK pentapeptide. Processing by SBT3.8 depended on the aspartic acid residue adjacent to the cleavage site. ProPSK1 processing was impaired in the sbt3.8 mutant. The data suggest that increased expression in response to osmotic stress followed by the post-translational processing of proPSK1 by SBT3.8 leads to the production of PSK as a peptide signal for stress mitigation.HighlightThe expression of phytosulfokine precursor genes and processing by the subtilase SBT3.8 are upregulated in response to osmotic stress for improved drought tolerance in Arabidopsis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Zhang ◽  
Lin-Feng Wang ◽  
Ting-Ting Li ◽  
Wen-Cheng Liu

Almost all abiotic stresses induce reactive oxygen species (ROS) overaccumulation, causing oxidative damages to plant cells. Catalase (CAT) plays a vital role in plant oxidative stress tolerance by scavenging stress-induced excess H2O2; thus, the identification of factors regulating catalase function will shed light on the underlying regulatory mechanisms. Here, we identified leucine aminopeptidase 2 (LAP2) as a novel CAT2-interacting protein and showed a mutual promotion effect of the two proteins in plant stress responses. LAP2 has a physical interaction with CAT2 in plant cells. The loss-of-function mutant of LAP2, lap2-3, is hypersensitive to salt or osmotic stress with increased ROS accumulation and malondialdehyde content and decreased catalase activity. The lap2-3 mutant has less CAT2 protein levels as CAT2 protein stability is impaired in the mutant. Scavenging excess ROS by glutathione or overexpressing CAT2 in the lap2-3 mutant recovers its hypersensitive phenotype to salt or osmotic stress. Further study showed that CAT2 promotes LAP2 hydrolysis activity with leucine-4-methylcoumaryl-7-amides as a substrate in vivo and in vitro, and thus, similar to the lap2-3 mutant, the cat2-1 mutant also has lower γ-aminobutyric acid content than the wild type. Together, our study reveals mutual promotion effects of CAT2 and LAP2 in conferring plant salt and osmotic stress tolerance.


2021 ◽  
Vol 22 (8) ◽  
pp. 4014
Author(s):  
Lin-Feng Wang ◽  
Ting-Ting Li ◽  
Yu Zhang ◽  
Jia-Xing Guo ◽  
Kai-Kai Lu ◽  
...  

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.


Sign in / Sign up

Export Citation Format

Share Document