Hormonal Signaling by PGPR Improves Plant Health Under Stress Conditions

  • Chaitanya Kumar Jha
  • Meenu Saraf


Changes in climate and/or resource management will mean that future crops, either unintentionally or deliberately, will receive insufficient irrigation necessarily drying the soil as well as limiting leaf expansion and gas exchange and, consequently, yield. The soil environment is a complex and highly heterogeneous system with its chemical, physical, and biological characteristics that vary significantly with location and time. Several chemical changes in soil are associated with plant-growth-promoting rhizobacteria (PGPRs). Some bacterial strains directly regulate plant physiology by mimicking synthesis of plant hormones, whereas others increase mineral and nitrogen availability in the soil as a way to augment growth. Such bacteria have been applied to a wide range of agricultural species for the purposes of growth enhancement, including increased seed emergence, plant weight, crop yields, and disease control. Various types of stress, including chilling, heat, wounding, pathogen infection, salt, metals, and nutritional stress, with increased damage, have been documented. However, the defined mechanisms involved in the use of PGPR which decrease the damage to plants that occurs under stress conditions is a potentially important adjuvant to agricultural practice in locales where stress is a major constraint. Of particular significance to the discussion here are rhizobacteria that can impact on plant hormone signaling pathways either by producing ABA (abscisic acid), auxins, gibberellin, and cytokinins or by mediating plant ethylene levels by producing ACC deaminase. Coinoculation of different rhizobacterial strains (that alter different signaling pathways) also may provide a ready-made solution. Depending on inoculum’s persistence, PGPRs may also provide an opportunity to target alterations in plant hormone status to specific growth stages or under particular stress conditions, under specific environmental conditions.


Salicylic Acid Jasmonic Acid Quorum Sense Induce Systemic Resistance Root System Architecture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Department of Microbiology, University School of SciencesGujarat UniversityAhmedabadIndia

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