Research On Ascarosides Production And Its Related Genes Expression In Monochamus Alternatus Regulated By Temperature

Ascarosides are multifunctional small-molecule signals prevalent in nematodes.Monochamus alternatus Hope is the medium of major invasive alien species-pine wood nematode,and the discovery of ascarosides in M.alternatus brings the study of ascarosides into the field of insects.On the basis of this paper,we selected the larvae from the wild and lab populations of M.alternatus and explored the production pattern of ascarosides and the expression pattern of the genes related to ascarosides biosynthesis under the condition of different temperatures.The main findings are as follows:1.Low-temperature can induce the larvae of field population of M.alternatus to produce a large amount of asc-C9 to delay its development process,but the asc-C9 would reduce or even disappear after the long-term of low-temperature treatment.Asc-C9 could be re-generated when restored it to the condition of higher temperature(10 ?,15 ?,20 ?),It shows that the production of asc-C9 has a certain temperature plasticity and is mainly controlled by low temperature.The content of asc-C9 in the epidermis of larvae was higher than that within the body,indicating that the distribution of asc-C9 was mainly in the epidermis of the last instar larvae.2.Due to the long-term of artificial acclimation,the development period of the indoor population of M.alternatus was significantly shortened,and no asc-C9 was produced in the lab population under different temperature treatments,thereby indicating that the asc-C9 had the function of retarding development of longicorn and was absent in the indoor population;The asc-C5 was detected in the epidermis of M.alternatus at 10 ? and 20?.After going through with the gradually incresing temperature,a larger amount of asc-C5 was detected inside the body.It is speculated that asc-C5 may be used as a developmental signal to induce the development of the larvae.3.The asc-C9 and asc-C5 produced in the larvae of M.alternatus are not permanent,and asc-C9 is stronger than asc-C5 on the reliability.It can be speculated that asc-C9 produced under low temperature conditions need to maintain the slow development of larvae in a certain period of time,while asc-C5 is more likely to be a signal to induce larvae development,which is more transient than that of asc-C9.And asc-C5 is more sensitive to changes in temperature.4.The expression of the bfp(bifunctional protein)gene was significantly down-regulated when the contents of asc-C9 increasing and was significantly up-regulated when the contents of asc-C5 increasing at the corresponding temperature treatments.Indicating that the expression of bfp gene has a significant correlation with the phenotypes of ascarosides production at different temperatures,suggesting that this gene may play a major regulatory role in it.In summary,this paper explored the regulation of ascarosides production and related genes expression in the wild and indoor populations of the M.alternates regulates by the tempreature changes.In order to establish the foundation for the further study on the function and intr:insic molecular mechanism of ascarosides in insects.