Priming of plant’s immune system: the future sustainable approach for tea improvement

Plant has an inherent or induced immunity to counter any abiotic or biotic stress. Such a response is possible due to physiological, molecular and cellular adaptations. Combined effect of abiotic and biotic stress can provoke cross-tolerance in plants, which may be synergistic and antagonistic with the involvement of protein kinases, transcription factors, phytohormones, and reactive oxygen species (ROS). Priming of a plant’s immune system leads to the accumulation of certain biomolecules like phytoalexins and PR proteins inside the plant system. Exogenous application of beta-aminobutyric acid, benzothiadiazole, azelaic acid has been reported to prime immune system in plants. Indian tea industry holds a vital position in the Indian economy. However, there is enormous crop loss yearly due to biotic and abiotic stress in tea. This happens despite using recommended agrochemicals and disease-resistant tea cultivars. Non judicious chemical practices have created environmental pollution and deposition of pesticide residues in made tea. Therefore, sustainable approach of tea improvement is of utmost requirement. This can be done by screening biomolecules followed by identifying their pathway genes responsible for enhanced cross-tolerance in tea plant. Then the candidate gene(s) can be over-expressed by transgenic approach. In the present review, we aim to address two important issues: (i) molecular approach to prime plant’s immune system, and (ii) sustainable approach to encounter abiotic and biotic stresses in tea plant by priming its immune system.