Isolation and characterization of a waterlogging-responsive gene involved in ethylene biosynthesis in chrysanthemum

Key message A full-length CgACO cDNA (KX644895) was isolated from chrysanthemum. The gene expression patterns were examined in two species with different resistances to waterlogging. Higher CgACO expression correlated with ethylene accumulation in the tolerant one. Abstract Soil waterlogging significantly affects natural vegetation and agricultural crops. It limits the growth of many plants, in particular those in moist areas. The phytohormone ethylene participates in a variety of signaling processes during abiotic stress responses. To gain a better understanding of the role of ethylene in waterlogging responses, we isolated the full-length cDNA of 1-aminocyclopropane-1-carboxylate oxidase ( CgACO) from chrysanthemum. We measured the expression levels of this gene in two Chrysanthemum species, Chrysanthemum zawadskii and C. nankingense , which differ in waterlogging tolerance. In roots of the sensitive species ( C. nankingense ), CgACO expression increased rapidly and reached its maximum at 12 h after treatment before decreasing. In contrast, in roots of the waterlogging-tolerant species ( C. zawadskii ), the expression of CgACO increased rapidly to a maximum at 12 h after treatment and maintained a high level up to 24 h after treatment. Higher CgACO expression possibly contributed to higher accumulation of ethylene in the waterlogging-tolerant species C. zawadski i. Taken together, our results support a previous observation reporting that C. zawadskii has a well-developed aerenchyma to adapt to waterlogging.