Domestic cats and other felids rub their faces and heads against catnip (Nepeta cataria) and silver vine (Actinidia polygama) and roll on the ground as a characteristic response. While this response is well known, its biological function and underlying mechanism remain undetermined. Here, we uncover the neurophysiological mechanism and functional outcome of this feline response. We found that the iridoid nepetalactol is the major component of silver vine that elicits this potent response in cats and other felids. Nepetalactol increased plasma β-endorphin levels in cats, while pharmacological inhibition of μ-opioid receptors suppressed the classic rubbing response. Rubbing behavior transfers nepetalactol onto the faces and heads of respondents where it repels the mosquito, Aedes albopictus. Thus, self-anointing behavior helps to protect cats against mosquito bites. The characteristic response of cats to nepetalactol via the μ-opioid system provides an important example of chemical pest defense using plant metabolites in nonhuman mammals.

No abstract

No abstract

Summary Fruit malformation is a major constrain in fruit production worldwide resulting in substantial economic losses. The farmers for decades noticed that the chilling temperature before blooming often caused malformed fruits. However, the molecular mechanism underlying this phenomenon is unclear. Here we examined the fruit development in response to cold stress in tomato, and demonstrated that short‐term cold stress increased the callose accumulation in both shoot apical and floral meristems, resulting in the symplastic isolation and altered intercellular movement of WUS. In contrast to the rapidly restored SlWUS transcription during the recovery from cold stress, the callose removal was delayed due to obstructed plasmodesmata. The delayed reinstatement of cell‐to‐cell transport of SlWUS prevented the activation of SlCLV3 and TAG1, causing the interrupted feedback inhibition of SlWUS expression, leading to the expanded stem cell population and malformed fruits. We further showed that the callose dynamics in response to short‐term cold stress presumably exploits the mechanism of bud dormancy during the seasonal growth, involving two antagonistic hormones, abscisic acid and gibberellin. Our results provide a novel insight into the cold stress regulated malformation of fruit.

The domestic cat is a very popular companion animal. However, there is very little work focusing on cat-specific physiology and behavior. In this review, we introduce our studies uncovering scent signals for species-and sex-recognition and the behavioral significance of the silver vine response in cats. Cat urine emits a specific catty smell. Our chemical analysis identified a sulfur-containing volatile organic compound, 3-mercapto-3-methyl-1-butanol, that is detectable in the urine of cats but not of dogs and humans. In addition, its level varies between sexes; its level is markedly higher in intact males than in castrated males or females. These indicate that the sulfur-containing compound is a urinary scent signal involved in species-and sex-recognition in cats. The other characteristic in cats is the behavioral response to silver vine, which comprises licking and chewing the plants, rubbing against the plants, and rolling over on the plants. Previous studies identified some bioactive compounds designated as matatabilactones from the plants, but little is known about why cats do the response to the plants. Our analyses found that nepetalactol which was missed in the plants is a potent bioactive compound for the response and stimulates the μ-opioid system which is responsible for the euphoria in humans. Nepetalactol has the repellent activity of pest insects such as mosquitoes. The rubbing and rolling responses to the plants transfer nepetalactol onto the feline fur that repels mosquitoes. The licking and chewing of the plants changes not only emission levels of nepetalactol and matatabilactones but also their contents which increase bioactivities toward cats and mosquitoes. These findings improve our understanding of the species-specific physiology and behavior in cats.