He-Ne laser irradiation in brinjal leads to metabolic rewiring and accumulation of bioactive components in fruits

Abstract

Seed germination, seedling growth and healthy, virtue-based, uniform crop establishment are essential for considerable agricultural productivity. Physical and chemical techniques are widely utilized to promote and speed up seed germination. Due to their low cost, lack of side effects, environmental friendliness, non-destructive and low-power irradiation techniques such as laser, magnetic energy, and ultrasound are utilized successfully in various crops. The most well-known and well-studied laser in the agriculture sector is the Helium-Neon laser. The current study aimed to examine potential interactions between plants and laser rays and the possible use of the He-Ne laser to alter and enhance fruit metabolites. Fruits from field-grown brinjal (Solanum melongena L.) plants were collected at various developmental stages, such as 15, 30, 45, and 60 days post-anthesis (DPA), from the un-irradiated control and laser-irradiated plants for fruit metabolite profiling. Principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) indicated that the 15 DPA groups showed the highest variation compared to the other developmental stages. The observed metabolites were primarily divided into primary and secondary metabolites and are related to amino acids and derivatives, alkaloids and glycoalkaloids, fatty acids, organic acids, sugars, sugar alcohol, and terpenoids. Furthermore, the secondary metabolites were identified and classified into pigments, alkaloids, terpenoids, flavonoids, and glycoalkaloids. In the fruit tissues of the laser-irradiated groups, it was observed that the shikimate-derived phenolic pathway was not altered. On the other hand, the mevalonate route (MVP) and methylerythritol 4-phosphate (MEP) pathways were changed in the fruit tissues from the laser irradiation groups, according to the characterization of sterols, terpenoids, and alkaloids. Based on our previous reports and the current analysis, the biostimulatory role of the He-Ne laser was revealed with significant alterations in the abundance of bioactive molecules and their associated pathways in the developmental stages of brinjal fruits.