Cold stress and the role of signalling hormones: A preliminary study on cold-tolerant high-altitude Himalayan rice genotypes

Abstract

Salicylic acid, methyl salicylate, jasmonic acid, and methyl jasmonate are important signaling hormones that play a significant role during plant stress. In the present study, the effect of cold stress on rice (Oryza sativa L.) leaves at the seedling stage was studied with regard to the level of these signaling hormones. Rice genotypes of Kashmir Himalayas were screened for cold tolerance under controlled conditions. The two contrasting (cold tolerant/susceptible) genotypes were selected to find whether these phytohormones play some role in cold stress. The seedlings of the two rice genotypes were subjected to cold stress at 5 °C and samples were collected at different time points. The level of Jasmonic acid and methyl jasmonate decreased sharply under cold treatment in both the contrasting genotypes. However, the concentration of these signalling hormones (JA and MeJA) was much higher in the resistant genotype than in the susceptible genotype. In the susceptible genotype, salicylic acid decreased sharply under cold treatment, while in the resistant genotype, it increased under cold. The concentration of methyl salicylate increased in both susceptible and resistant genotypes under cold stress.