JIA-2019-11

2583 CUI Dong-nan et al. Journal of Integrative Agriculture 2019, 18(11): 2579–2588 associated with maternal line (Delinger 2002; Timer et al. 2010). For L . migratoria , the maternal photoperiodic response induces embryonic diapause allowing the eggs to survive under unfavourable environmental conditions (Tanaka 1994). How female adults transfer the environmental information to their offspring and induce egg diapause is still unclear. Tu et al. (2015) and Hao et al. (2017) have studied the effect of temperature on diapause in migratory locusts and they determined the optimum temperature of 27°C for locusts to enter diapause. We primarily examined the maternal photoperiodic response on oocytes while Tu et al. (2015) and Hao et al. (2017) focused on the embryonic stage of locust. As part of developing a better understanding of the underlying biochemical processes to diapause induction, we performed a comparative analysis of proteomes of both non-diapause and diapause eggs via a label-free approach and qRT-PCR was used for verification. Most HSPs are synthesized in response to various stresses, and some of them are essential to insects’ development (Chapuis et al. 2011) and have been associated with insect diapause (Denlinger 2002; Rinehart et al. 2007). Unlike up-regulated HSPs in response to stress, HSPs vary considerably during diapause among different species and different physiological stages of the insect. At the transcriptional level, HSP20.7 and HSP90 in diapause embryos of the cricket, Allonemobius socius , were significantly decreased as compared to the non-diapause cohort, while HSP70 transcripts were unchanged (Reynolds and Hand 2009). Using qRT-PCR to verify the transcriptional level of HSP20.7, we observed a significantly lower level in diapause eggs than that in non-diapause eggs, which was consistent with the change in protein levels. Additionally, HSP70 was up-regulated in diapause eggs but the difference was insignificant. In diapause and non-diapause eggs, HSP90, HSP20.5, HSP23.8, HSP19.8, and HSP21.1 were expressed but without any significant differences between the two groups. Insects are able to survive through a long diapause period by increasing their energy reserves. However, previous studies on insect storage proteins show that not all proteins exhibit the same trends in expression during Table 2 Significantly up-regulated proteins in diapause eggs No. Protein Significance Fold change 1 Protein arginine N-methyltransferase 3 60.69 27.53 2 Eukaryotic translation initiation factor 4E transporter partial 13.16 4.83 3 Hexamerin-like protein 4 26.03 3.29 4 Xanthine dehydrogenase partial 28.56 3.11 5 ABC transporter G family member 23 20.77 2.87 6 Probable small nuclear ribonucleoprotein E 25.86 2.53 7 60S ribosomal protein L10 13.21 2.41 8 Transcription factor HES-4 21.23 2.38 9 Multidrug resistance-associated protein 4-like 14.83 2.11 10 60S ribosomal protein L23 21.49 1.87 11 Protein MEMO1 20.74 1.79 12 Adenosylhomocysteinase putative 20.05 1.79 13 Small nuclear ribonucleoprotein Sm D3 22.52 1.75 14 60S ribosomal protein L6 16.40 1.68 15 IQ domain-containing protein E 22.39 1.65 16 Histone H1-III 51.26 1.64 17 Tropomyosin-2 isoform X7 13.41 1.61 18 40S ribosomal protein S25 14.40 1.60 19 QN1-like protein 20.40 1.60 20 Eukaryotic translation initiation factor 3 subunit J 20.64 1.57 21 Lysosome-associated membrane glycoprotein 1 18.31 1.54 22 Hypothetical protein TcasGA2 18.11 1.53 23 Hypothetical protein L798 22.21 1.53 24 ABCC4-like protein 13.07 1.51 Table 3 Significantly down-regulated proteins in diapause eggs No. Protein Significance Fold change 1 Very long-chain specific acyl-CoA dehydrogenase mitochondrial 38.62 0.03 2 Transforming acidic coiled-coil- containing protein 3-like 18.80 0.06 3 Greglin 26.54 0.08 4 Transformer-2 protein-like protein beta 28.43 0.09 5 Serine/threonine-protein kinase OSR1 19.5? 0.10 6 Actin-interacting protein 1 22.94 0.12 7 Asparagine synthetase 17.00 0.13 8 Synaptic vesicle membrane protein VAT-1 homolog isoform X2 17.87 0.14 9 Hrp65 protein 15.57 0.14 10 Carboxylesterase 23.43 0.15 11 Aromatic-L-amino-acid decarboxylase 14.26 0.15 12 Protein TFG 24.69 0.17 13 Nicotinate phosphoribosyltransferase isoform X3 46.74 0.17 14 Cytochrome P450 307A1 13.88 0.17 15 Heterogeneous nuclear ribonucleoprotein A1 putative 17.38 0.18 16 Mannose-1-phosphate guanyltransferase beta 18.44 0.19 17 Sorting nexin-2 20.33 0.20 18 Variable lymphocyte receptor partial 19.95 0.20 19 ATP-binding cassette sub-family E member 1 13.78 0.21 20 WD and tetratricopeptide repeats protein 1 partial 13.98 0.23