The deleterious effects of chitosan application on red chili pepper growth and capsaicin biosynthesis under drought stress
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Abstract
Abstract. Aziz MA, Esyanti RR, Meitha K, Dwivany FM. 2022. The deleterious effects of chitosan application on red chili pepper growth and capsaicin biosynthesis under drought stress. Asian J Trop Biotechnol 19: 52-61. The production of red chili pepper is often impeded by drought. Chitosan is considered as a promising alternative natural fertilizer and defense elicitor. This study aimed to investigate the effect of chitosan on red chili plant growth and capsaicin biosynthesis under drought stress. At the onset of the generative phase, the plant was subjected to 1 mg mL-1 chitosan, 50% drought, or chitosan-drought treatment. Observations were made on several growth parameters, yield, PAL expression, PAL activity, and capsaicin content. The results showed that chitosan-drought treatment significantly decreased plant growth and yield. The PAL gene expression was up-regulated around 129-fold higher than control, followed by increased PAL activity and capsaicin content about 1.22 and 1.39-fold higher than control, respectively. PAL activity and capsaicin content on chitosan-drought treated plants were lower than on individual chitosan applications. Therefore, we suggested that the double treatment of chitosan-drought might decrease red chili pepper production and capsaicin content. Interestingly, the individual chitosan treatment significantly increased PAL expression level, PAL activity, and capsaicin content compared to other treatments. Furthermore, it was suggested that chitosan might play a role in the red chili plant defense system involving capsaicin biosynthesis through the phenylpropanoid pathway.