Insights into salt tolerance of mustard (Brassica juncea L. Czern & Coss): A metabolomics perspective

Abstract

Salt stress is one of the key abiotic factor which leads to reduced global agricultural productions through negatively impacting the growth and development of crops. Indian mustard ( Brassica juncea ), the most important cruciferous crop with significant nutritional and medicinal values, is majorly affected by salt stress. In this study, we explored the global metabolomic response of two Indian mustard genotypes, CS 60 and CS 245–2–80–7 grown under salt stress for different time periods to unleash the role of differentially accumulated metabolites and relevant metabolic pathways involved in the salt tolerance mechanism. A total of 608 known compounds were detected from 4119 metabolites using DionexUltiMate ® 3000 Ultra High-Performance Liquid Chromatographic System combined with “ Q Exactive™ Plus Orbitrap™ Mass Spectrometer (UHPLC-MS/MS) analysis, from which 111 significantly altered metabolites in both genotypes were selected based on t -test and VIP score values. Using MetPa from MetaboAnalyst 5.0 platform, metabolic pathways with significant impact values were considered to be involved in the salt tolerance mechanism. Increased accumulation of metabolites and detected relevant pathways majorly regulating the anti-oxidant defense system gives CS 60, a high yielding variety, an edge against the genotype CS 245–2–80–7, which might be the chief tolerance mechanism to withstand salt stress. • Metabolomics approach on Indian mustard genotypes (Salt tolerant and sensitive) under salt stress at seedling stage, demonstrating the role of metabolites involved in salt tolerance mechanism. • Photosynthetic attributes were more active in CS 60 compared to genotype CS 245–2-80–7 under the influence of salt stress. • Under salt stress, CS 60 showed 63 DAMs while CS 245–2-80–7 exhibited only 48 DAMs, demonstrating the tolerance against salt treatments. • Relevant pathways (pre-dominantly anti-oxidant defense system) protected salt stressed CS 60 seedlings by preventing salt induced osmotic stress and oxidative stress.