title: The environmental endocrine disruptor, bisphenol A, affects germination, elicits stress response and alters steroid hormone production in kiwifruit pollen.
abstract: In vitro toxicity of the endocrine disruptor bisphenol A (BPA) to pollen, the male haploid generation of higher plants, was studied. BPA caused significant inhibition of both tube emergence and elongation of kiwifruit pollen in a dose-dependent manner, beginning at 10 mg · l(-1); morphological changes to tubes were also detected. Despite strong inhibition of pollen tube production and growth, a large percentage of treated cells remained viable. Immunoblotting experiments indicated that levels of BiP and 14-3-3, which are proteins involved in stress response, substantially increased in BPA-treated pollen compared to controls. The increases were dose-dependent in the range 10-50 mg · l(-1) BPA, i.e. even when germination ability was completely blocked. Steroid hormones (17 β-estradiol, progesterone and testosterone) were detected in kiwifruit pollen, and their levels increased during germination in basal medium. In a BPA treatment of 30 mg · l(-1), larger increases in both estrogen and testosterone concentrations were detected, in particular, a six-fold increase of 17 β-estradiol over control concentration (30 min). The increased hormone levels were maintained for at least the 90 min incubation. Increasing concentrations of exogenous testosterone and 17 β-estradiol increasingly inhibited pollen tube emergence and elongation. Current data for BPA-exposed kiwifruit pollen suggest a toxicity mechanism that is at least in part based on a dramatic imbalance of steroid hormone production during tube organisation, emergence and elongation. It may be concluded that BPA, a widespread environmental contaminant, can cause serious adverse effects to essential pollen functions. On a broader scale, this chemical poses a potential risk to the reproductive success of higher plants.
authors.affiliation: Dipartimento di Biologia Evoluzionistica Sperimentale, Università di Bologna, Bologna, Italy. anna.speranza@unibo.it
authors.forename: A
authors.initials: A
authors.lastname: Speranza
authors.forename: P
authors.initials: P
authors.lastname: Crosti
authors.forename: M
authors.initials: M
authors.lastname: Malerba
authors.forename: O
authors.initials: O
authors.lastname: Stocchi
authors.forename: V
authors.initials: V
authors.lastname: Scoccianti
mesh_terms: D029042:Actinidia / Q000187:drug effects* / Q000378:metabolism; D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors / Q000494:pharmacology; D018525:Germination / Q000187:drug effects*; D010636:Phenols / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000096:biosynthesis*; D011058:Pollen / Q000187:drug effects* / Q000378:metabolism; D013256:Steroids / Q000096:biosynthesis*; D013312:Stress, Physiological / Q000187:drug effects*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D010636:Phenols; D010937:Plant Growth Regulators; D013256:Steroids; C006780:bisphenol A; D000098826:Bisphenol A Compounds