Polyamines regulate strawberry fruit ripening by abscisic acid, auxin, and ethylene (Plant Physiol)

Polyamines, which include putrescine [NH₂(CH₂)₄NH₂], spermidine [NH₂(CH₂)₄NH(CH₂)₃NH₂], and  spermine [NH₂(CH₂)₃NH(CH₂)₄NH(CH₂)₃NH₂], are widespread in nature. Although their mechanisms of action remain largely unresolved, they have demonstrated roles in plants ranging from abiotic stress tolerance to fruit ripening. Guo, Wang et al. examined the contributions of polyamines to strawberry fruit ripening. They showed that spermidine levels increase during ripening, and that exogenous application of spermidine or spermine accelerates ripening. Altering polyamine levels by alterine the expression of a biosynthetic enzyme had the corresponding effect, largely mediated through other hormones. (Summary by Mary Williams) Plant Physiol. 10.1104/pp.18.00245