Researchers at the Rajiv Gandhi Centre for Biotechnology (RGCB) here have shown that using ‘defence priming’ to strengthen the plant immune system, avoiding pesticides and toxic chemicals in the process, can offer better crop protection in pepper.
The findings of the study were recently published in the journal Frontiers in Plant Science.
For the study, Glycol chitosan, a water soluble, non-toxic polymer known to induce plant defence, was used to ‘prime’ the leaves of pepper plants.
S. Manjula, who led the team of researchers, said there was convincing evidence to prove the potential of ‘priming’ or ‘sensitising’ to protect pepper plants from ‘foot-rot,’ a devastating disease affecting the leaves, stems, and roots in the nursery and pepper plantations, a statement said.
Diseases and pests posed serious threats to sustainable yields of commercial black pepper ( Piper nigrum). The major pathogen responsible for foot-rot is Phytophthora capsici. It was observed that Glycol chitosan treatment offered protection from the severity of foot-rot and caused a significant delay in the appearance of symptoms.
The priming effect was manifested through enhanced expression of critical genes of the plant immunity pathways, according to the statement.
Further, the study also revealed a significant increase in ‘Piperine’ accumulation in leaves as a result of the priming. Piperine is largely responsible for the pungent taste of black pepper.
The report was also the first to offer strong molecular evidence for the advantage of defence priming in black pepper plant by improving crop protection.
The study had implications not just for pepper but for several other crops as well, RGCB Director Chandrabhas Narayana said. Defence priming had the potential to significantly reduce the use of high-risk pesticides and synthetic chemicals, Prof. Narayana said.
Dr. Manjula said plants possessed a robust, efficient immune system. They could be primed for better defence response by specific environmental, biological, and chemical conditions. “Increasing the efficiency of the plant immune system would reduce the need to rely on unsustainable pesticides,” she said.
She added that more work was needed to establish the durability of priming and to optimise the method of treatment for large-scale commercial application. Further studies on the potential of seed priming to evaluate its persistence through successive generations, a phenomenon called ‘immune memory,’ too would be undertaken.
