A protein repairing enzyme, PROTEIN L- ISOASPARTYL METHYLTRANSFERASE is involved in salinity stress tolerance by increasing efficiency of ROS-scavenging enzymes

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized anAPX(CaAPX) gene fromCamellia azalea. Quantitative real-time PCR (qRT-PCR) analysis showed thatCaAPXwas expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated withCaAPXexpression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes includingCu/Zn-SOD,CAT,DHAR, andMDHAR, and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role ofCaAPXto orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related toCaAPXexpression and provides insights to breed crops with high temperature tolerances.

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Plant Growth-Promoting Rhizobacteria Enhance Salinity Stress Tolerance in Okra through ROS-Scavenging Enzymes

BioMed Research International ◽

10.1155/2016/6284547 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 144

Author(s):

Sheikh Hasna Habib ◽

Hossain Kausar ◽

Halimi Mohd Saud

Keyword(s):

Plant Growth ◽

Stress Tolerance ◽

Salinity Stress ◽

Acc Deaminase ◽

Plant Growth Promoting Rhizobacteria ◽

Antioxidant Enzyme Activities ◽

Ros Scavenging ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Salinity Stress Tolerance

Salinity is a major environmental stress that limits crop production worldwide. In this study, we characterized plant growth-promoting rhizobacteria (PGPR) containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase and examined their effect on salinity stress tolerance in okra through the induction of ROS-scavenging enzyme activity. PGPR inoculated okra plants exhibited higher germination percentage, growth parameters, and chlorophyll content than control plants. Increased antioxidant enzyme activities (SOD, APX, and CAT) and upregulation of ROS pathway genes (CAT, APX, GR, and DHAR) were observed in PGPR inoculated okra plants under salinity stress. With some exceptions, inoculation withEnterobactersp. UPMR18 had a significant influence on all tested parameters under salt stress, as compared to other treatments. Thus, the ACC deaminase-containing PGPR isolateEnterobactersp. UPMR18 could be an effective bioresource for enhancing salt tolerance and growth of okra plants under salinity stress.

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