Association of Biochemical Changes In Cold Treated Sour Orange Seedlings to Increase Asian Citrus Psyllid Infestation

 Changes in the levels of different polyphenols and polyamines in different plant spices have been implicated in modulating feeding behaviors and oviposition of several insects. Our studies showed that citrus plants exposed to cold temperature, (4ºC) for seven days and then brought in to room temperature for 24 hours, attracted more psyllids (more than twice) than the plants that were continuously kept at room temperature (26±1 ºC). We therefore investigated the levels of polyphenols and polyamines in citrus leaves that were given a chilling treatment and compared the levels of these compounds to the levels in the control plants that were kept at room temperature. The results of these experiments showed distinct changes in some polyphenols and polyamines in the cold treated plants.  For example, levels of rutin and  chlorogenic acid decreased in the leaves of the sour orange seedlings that were given chilling treatment before bringing to room temperature (and keeping at room temperature for 24 hrs before the test) as compared with levels of respective compounds in leaves of control plants. Polyamine levels (e.g., Putrescine) increase more than two time in cold treated plants measured 2 hours after bring the plants to room temperature but decline sharply in plants that were kept for 24 hrs at room temperature after chilling treatment . This data and its relation to attractiveness to Asian citrus psyllids will be presented.