Dissection of phenylpropanoid pathway during salt stress in cotton (<em>Gossypium hirsutum</em> L.)

Abstract

Salt stress is an abiotic stress in cotton (G. hirsutum L.) that affects evenly yield. The present investigation carried out to study the significance of integrative biochemical and molecular approaches against salt stress in cotton. Four different verities, two salt tolerant (G.Cot.-16, GISV.218) and two susceptible (G. Cot.10, G.Cot.-100) were used screened at different salinity levels viz., 0.8 dS/m, 3 dS/m, 7 dS/m and 10 dS/m. Bio-chemical and molecular parameters analysed at seedling (15 DAS) and squaring stage (45 DAS). Biochemical traits like Protein content, total phenol content and Proline content was found to be increased with increasing salinity levels. Enzyme activity related to phenylpropanoid pathway (PAL, C4H and C3H) was found to be also increased with the advancement in salt stress, hence it implies possible role of these enzymes in imparting tolerance to salt stress in cotton. Reactive oxygen species (ROS) scavenging enzymes such as SOD, POD, CAT and PPO recorded increase in their activity at both seedling and squaring stages with increasing salinity levels. Expression analysis of key genes of phenylpropanoid pathway viz. PAL, C4H (C4H1 and C4H2) revealed maximum fold expression of PAL and C4H1 in the leaves, whereas least fold expression was observed for C4H2. Thus, it may be concluded that phenylpropanoid pathway play significant role in imparting tolerance against salt stress in cotton.