MAN5, a Glycosyl Hydrolase Superfamily Protein, Is a Key Factor Involved in Cyanide-Promoted Seed Germination in .

Seed germination is the complex adaptive trait of higher plants influenced by a large number of genes and environmental factors. Numerous studies have been performed to better understand how germination is controlled by various environmental factors and applied chemicals, such as cyanide. However, still very little is known about the molecular mechanisms of how extrinsic signals regulate seed germination. Our and previous studies found that non-lethal cyanide treatment promotes seed germination, but the regulatory mechanism is unclear. In this study, we found that a low concentration of cyanide pretreatment significantly enhanced the expression of endo-β-mannanase 5 () gene in , and the mutation of this gene impaired cyanide-mediated seed germination. In contrast, overexpression of gene enhanced Arabidopsis seed germination ability under both normal and salt stress conditions. Further studies showed that the expression of the gene was negatively regulated by ABA insensitive 5 (ABI5); In mutant seeds, the expression of the gene was increased and the seed germination rate was accelerated. Additionally, cyanide pretreatment markedly reduced the gene expression of in Arabidopsis seeds. Taken together, our data support the involvement of as a key gene in cyanide-mediated seed germination and confirm the role of ABI5 as a critical negative factor involved in cyanide-regulated gene expression.