长短光照桃小食心虫保幼激素动态及相关基因在脱果时的表达差异

Dynamic changes of juvenile hormone and differential expression of related genes in off-fruit larvae of Carposina sasakii(Lepidoptera:Carposinidae)under different photoperiod

【目的】在长光照和短光照条件下,桃小食心虫Carposina sasakii Matsumura脱果老熟幼虫分别进行非滞育和滞育发育,探究保幼激素(JH)在2种发育方向调控中的差异,以及该差异过程JH合成代谢相关基因表达的分子基础。【方法】试验首先采用Illumina HiSeqTM 4000测序平台测定了2种生长条件下老熟幼虫头部转录组,qPCR验证转录组数据的准确性,并筛选差异表达的JH合成代谢相关基因;然后结合2种发育方向JH丰度变化差异,进一步分析这些JH相关基因在此过程中的作用。【结果】试验共获得了39330876条序列读取片段,有效转录组数据44.35 Gb(SRA登录号:PRJNA495711),组装拼接获得56723个单基因簇(unigene),平均长度963 bp,其中1 kb以上的unigene有16343条,经过BLASTX比对成功注释27180个unigene。2种光照条件下桃小脱果老熟幼虫JH丰度无显著差异;长光照桃小老熟幼虫进行非滞育发育,2 d后进入长茧,虫体JH丰度比初脱果少量增加;而短光照老熟幼虫滞育发育进入圆茧,JH含量比2 d前初脱果增加了3倍,JH丰度显著高于同时期长茧内幼虫。2种光照下脱果老熟幼虫存在993个差异表达基因,包括7个JH合成代谢相关基因;其中jhamt在短光照老熟幼虫表达量是长光照的3.4倍,jheh1、jheh2、jheh3和jheh4在短光照老熟幼虫头部表达量分别是长光照的19.6、1.9、4.3和0.4倍,jhbp1和jhbp2在的2.7和20.5倍。【结论】研究获得了桃小2种光周期下老熟幼虫高质量的转录组数据,明确了桃小进入圆茧滞育需要JH丰度大幅升高的过程,筛选并分析了JH合成代谢相关的7个差异表达基因,为进一步研究桃小进入滞育过程中JH调控的分子机制奠定了基础。

【Objective】Under long and short light photoperiods,experiments were conducted on non-diapause and diapause development of off-fruit mature larvae of Carposina sasakii Matsumura to investigate the differences in the regulation of juvenile hormone(JH)in the two developmental directions and the molecular mechanism of the expression of genes related to JH anabolism during this differential process.【Method】Illumina HiSeqTM 4000 sequencing platform was used to determine the head transcriptome of mature larvae under two growth conditions.QPCR was used to verify the accuracy of transcriptome data,and differentially expressed GENES related to JH anabase were screened.Then,the role of these JH-related genes in this process was further analyzed based on the variation of JH abundance in the two developmental directions.【Result】A total of 39330876 sequence reading fragments containing 44.35 Gb(SRA accession no:PRJNA495711)valid data were obtained.A total of 56723 unigenes clusters were assembled and spliced,with an average length of 963 bp,including 16343 unigene clusters larger than 1 KB.After BLASTX comparison,27180 unigene clusters were annotated successfully.There was no significant difference in JH abundance between the two light photoperiods.After 2 days of non-diapause development,the abundance of JH increased slightly compared with the initial off-fruit larvae.However,the content of JH in diapause larvae was 3 times higher than that in diapause larvae of 2 d before,and the abundance of JH was significantly higher than that in long cocoon larvae at the same time.There were 993 differentially expressed genes,including 7 genes related to JH anabolism.The expression of jhamt in the head of mature larvae under the short light condition was 3.4 times of that under the long light condition,and the expression of jheh 1,jheh2,jheh3 and jheh4 in the head of mature larvae under the short light photoperiod was 19.6,1.9,4.3 and 0.4 times of that under the long light condition,respectively.The expression levels of jhbp1 and jhbp2 in the heads of short-lighted mature larvae were 2.7 and 20.5 times that of the long-lighted,respectively.【Conclusion】The high quality transcriptome data of mature larvae of C.sasakii under two light conditions were obtained through this research,and it was made clear that the larvae need to increase the concentration of JH in the process of diapause and 7 differential expression genes related to anabolism in the process were screened and analyzed,which had laid a foundation for further studying the molecular metabolism of the regulation of JH in the diapause development of mature larvae of C.sasakii.