scholarly journals Arabidopsis AtDjA3 Null Mutant Shows Increased Sensitivity to Abscisic Acid, Salt, and Osmotic Stress in Germination and Post-germination Stages

2016 ◽  
Vol 7 ◽  
Author(s):  
Silvia Salas-Muñoz ◽  
Aída A. Rodríguez-Hernández ◽  
Maria A. Ortega-Amaro ◽  
Fatima B. Salazar-Badillo ◽  
Juan F. Jiménez-Bremont
Keyword(s):  
Abscisic Acid ◽  
Osmotic Stress ◽  
Acid Salt ◽  
Null Mutant ◽  
Increased Sensitivity ◽  
Salt And Osmotic Stress

Evidence for two recA genes mediating DNA repair in Bacillus megaterium

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 775-787 ◽  
Author(s):  
Hannes Nahrstedt ◽  
Christine Schröder ◽  
Friedhelm Meinhardt
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mitomycin C ◽  
Bacillus Megaterium ◽  
Functional Complementation ◽  
Homologous Gene ◽  
Gene Products ◽  
Null Mutant ◽  
Promoter Regions ◽  
Increased Sensitivity

Isolation and subsequent knockout of a recA-homologous gene in Bacillus megaterium DSM 319 resulted in a mutant displaying increased sensitivity to mitomycin C. However, this mutant did not exhibit UV hypersensitivity, a finding which eventually led to identification of a second functional recA gene. Evidence for recA duplicates was also obtained for two other B. megaterium strains. In agreement with potential DinR boxes located within their promoter regions, expression of both genes (recA1 and recA2) was found to be damage-inducible. Transcription from the recA2 promoter was significantly higher than that of recA1. Since a recA2 knockout could not be achieved, functional complementation studies were performed in Escherichia coli. Heterologous expression in a RecA null mutant resulted in increased survival after UV irradiation and mitomycin C treatment, proving both recA gene products to be functional in DNA repair. Thus, there is evidence for an SOS-like pathway in B. megaterium that differs from that of Bacillus subtilis.

scholarly journals Mechanisms of Adaptation to Nitrosative Stress in Bacillus subtilis

2007 ◽  
Vol 189 (8) ◽  
pp. 3063-3071 ◽  
Author(s):  
Annika Rogstam ◽  
Jonas T. Larsson ◽  
Peter Kjelgaard ◽  
Claes von Wachenfeldt
Keyword(s):  
Bacillus Subtilis ◽  
Stress Proteins ◽  
Nitrosative Stress ◽  
Vital Role ◽  
Null Mutant ◽  
Truncated Hemoglobin ◽  
Sigma B ◽  
Nitrosonium Cation ◽  
Mechanisms Of Adaptation ◽  
Increased Sensitivity

ABSTRACT Bacteria use a number of mechanisms for coping with the toxic effects exerted by nitric oxide (NO) and its derivatives. Here we show that the flavohemoglobin encoded by the hmp gene has a vital role in an adaptive response to protect the soil bacterium Bacillus subtilis from nitrosative stress. We further show that nitrosative stress induced by the nitrosonium cation donor sodium nitroprusside (SNP) leads to deactivation of the transcriptional repressor NsrR, resulting in derepression of hmp. Nitrosative stress induces the sigma B-controlled general stress regulon. However, a sigB null mutant did not show increased sensitivity to SNP, suggesting that the sigma B-dependent stress proteins are involved in a nonspecific protection against stress whereas the Hmp flavohemoglobin plays a central role in detoxification. Mutations in the yjbIH operon, which encodes a truncated hemoglobin (YjbI) and a predicted 34-kDa cytosolic protein of unknown function (YjbH), rendered B. subtilis hypersensitive to SNP, suggesting roles in nitrosative stress management.

Tomato Asr1 mRNA and protein are transiently expressed following salt stress, osmotic stress and treatment with abscisic acid

Plant Science ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Hagit Amitai-Zeigerson ◽  
Pablo A. Scolnik ◽  
Dudy Bar-Zvi
Keyword(s):  
Abscisic Acid ◽  
Salt Stress ◽  
Osmotic Stress

scholarly journals Arabidopsis SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2 inhibit WRKY75 function in abscisic acid-mediated leaf senescence and seed germination

2021 ◽  
Author(s):  
Haiyan Zhang ◽  
Liping Zhang ◽  
Yunrui Ji ◽  
Yifen Jing ◽  
Lanxin Li ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Leaf Senescence ◽  
Chromatin Immunoprecipitation ◽  
Sigma Factor ◽  
Dependent Manner ◽  
Negative Regulators ◽  
Factor Binding ◽  
Physiological Processes ◽  
Increased Sensitivity

Abstract The plant-specific VQ gene family participates in diverse physiological processes but little information is available on their role in leaf senescence. Here, we show that the VQ motif-containing proteins, Arabidopsis SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2 are negative regulators of abscisic acid (ABA)-mediated leaf senescence. Loss of SIB1 and SIB2 function resulted in increased sensitivity of ABA-induced leaf senescence. In contrast, overexpression of SIB1 significantly delayed this process. Moreover, biochemical studies revealed that SIBs interact with WRKY75 transcription factor. Loss of WRKY75 function decreased sensitivity to ABA-induced leaf senescence, while overexpression of WRKY75 significantly accelerated this process. Chromatin immunoprecipitation assays revealed that WRKY75 directly binds to the promoters of GOLDEN 2-LIKE1(GLK1) and GLK2, to repress their expression. SIBs repress the transcriptional function of WRKY75 and negatively regulate ABA-induced leaf senescence in a WRKY75-dependent manner. In contrast, WRKY75 positively modulates ABA-mediated leaf senescence in a GLK-dependent manner. In addition, SIBs inhibit WRKY75 function in ABA-mediated seed germination. These results demonstrate that SIBs can form a complex with WRKY75 to regulate ABA-mediated leaf senescence and seed germination.

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