Morphological characteristics and gene expression of Aldrichina grahami egg in different developmental stages

ObjectiveTo examine the morphological characteristics and differential gene expression of Aldrichina grahami egg in the different developmental stages.MethodsAfter Aldrichina grahami layed eggs(0 h), the eggs were collected every 4 hours until the eggs hatched into larvae.The morphological characteristics of Aldrichina grahami egg in different developmental stages were observed with scanning electron microscopy.The total RNA the eggs at every develop-mental stage was extracted.The expression levels of bicoid, slalom,and chitin synthase gene were determined with real-time flourescence quantitative PCR.Statistic analyses were performed with SPSS 19.0.ResultsThe scanning electron microscope images showed that the morphological change of the eggs were not obvious in the first 4 hours, with protuberance around the micropyle.At the 8th hour the surface around the micropyle was smooth and the shape of micropyle was visible.At the 12th hour, the micropyle disappeared,with shrinking around the place of the micropyle and the shrinking was more obvious at the 16th hour.After 18 hours the larvae hatched from the eggs.Real-time fluorescence quantitative PCR results indicated that the expression levels of bicoid,slalom and chitin synthase genes in the Aldrichina grahami eggs changed regularly with the developmental stages; the change of bicoid gene expression was not obvious from 0 to 8th hour and at 12th hour the expression level was the highest, with a CT value of 4.19±0.04;the lowest slalom gene expression appeared at 4th hour and the highest at 12th hour, with the CT values of 4.05±0.01and 6.20±0.03;the highest chitin synthase gene expression appeared at 8th hour and the lowest at 12th hour, with the CT values of 5.80±0.01 and 4.38±0.02,respectively;the expression levels were different in different development stages and there were significant difference in CT values between different developmental stages of Aldrichina grahami eggs(all P<0.05).ConclusionThe morphological characteristics of Aldrichina grahami eggs changes with the development stage.The expression levels of bicoid,slalom,and chitin synthase genes of Aldrichina grahami eggs are different in various development period.