Comparative Metabolomic Profiling Reveals Key Secondary Metabolites Associated with High Quality and Nutritional Value in Broad Bean (Vicia faba L.).

High quality and nutritional benefits are ultimately the desirable features that influence the commercial value and market share of broad bean (Vicia faba L.). Different cultivars vary greatly in taste, flavor, and nutrition. However, the molecular basis of these traits remains largely unknown. Here, the grain metabolites of the superior Chinese landrace Cixidabaican (CX) were detected by a widely targeted metabolomics approach and compared with the main cultivar Lingxiyicun (LX) from Japan. The analyses of global metabolic variations revealed a total of 149 differentially abundant metabolites (DAMs) were identified between these two genotypes. Among them, 84 and 65 were up- and down-regulated in CX compared with LX. Most of the DAMs were closely related to healthy eating substances known for their antioxidant and anti-cancer properties, and some others were involved in the taste formation. The KEGG-based classification further revealed that these DAMs were significantly enriched in 21 metabolic pathways, particularly in flavone and flavonol biosynthesis. The differences in key secondary metabolites, including flavonoids, terpenoids, amino acid derivates, and alkaloids, may lead to more nutritional value in a healthy diet and better adaptability for the seed germination of CX. The present results provide important insights into the taste/quality-forming mechanisms and contributes to the conservation and utilization of germplasm resources for breeding broad bean with superior eating quality.

Genotypic differences in leaf secondary metabolism, plant hormones and yield under alone and combined stress of drought and salinity in cotton genotypes.

Drought and salinity stress highly affect the plant growth and production around the world. Secondary metabolites play a main role in adaptation to the environment and in overcoming stress conditions. In order to investigate the effect of drought and salinity, alone or in combination, on secondary metabolism-related enzyme activities, plant hormones and yield parameters, a greenhouse pot experiment was conducted using two cotton genotypes Zhongmian 23 (salt tolerant) and Zhongmian 41 (salt sensitive). Results showed that single and combined drought and salinity stresses caused remarkable decrease in plant height, bolls and lint yield in the order as follows: D + S > salinity > drought, and Zhongmian 41 > Zhongmian 23. Lower H2 O2 and superoxide but higher proline content and secondary metabolism-related enzyme activities were observed in Zhongmian 23 under drought and salinity, both alone and combined, compared with control in Zhongmian 41. Our findings suggest that controlling reactive oxygen species (ROS) levels and increasing activities of secondary metabolism-related enzymes in Zhongmian 23 might be an effective mechanism to reduce the negative effects of drought and salinity stress. However, cinnamyl alcohol dehydrogenase (CAD), and shikimate dehydrogenase (SKDH) activities were markedly decreased in Zhongmian 41 under salinity stress alone as compared with control. Meanwhile, Zhongmian 23 had higher expression levels of genes related to secondary metabolism (c.f. phenylalanine ammonia-lyase, PAL; polyphenol oxidase, PPO and CAD) under the three stresses compared to Zhongmian 41. The content of flavonoids and phenols were significantly enhanced under drought and D + S, with higher accumulation in Zhongmian 23. Phenols content in Zhongmian 23 remained unchanged under salinity as relative to control, but were significantly reduced in Zhongmian 41. In addition, callose content, chitinase activities and abscisic acid (ABA) and Indole-3-acetic acid (IAA) were more induced in Zhongmian 23 under drought, salinity and D + S, than in Zhongmian 41. Our results suggest that high tolerance to D + S stress in Zhongmian 23 is closely related to elevated callose, chitinase, flavonoids and phenols contents and higher secondary metabolism-related enzyme activities and their transcript levels.