Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress

Abstract

The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (−11 to 43°C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42°C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.

Molecular Characterization of Heat-Induced HSP11.0 and Master-Regulator HSF from Cotesia chilonis and Their Consistent Response to Heat Stress

“…Cchsp11.0 and Cchsf expression increased at the 15 min time point in response to heat stress and then declined until another round of induction 2 h. The decreased expression of Cchsp11.0 at 30 min and 1 h may be related to the regulation of other HSPs [ 2 ], and the decline in Cchsf expression at these times may be related to the negative regulation of HSF by HSP. Previous studies showed that many small heat shock proteins have their maximum expression after 2 h of temperature treatment, such as Cshsp702 , Cshsp19.8 , Cshsp21.7b , Cshsp21.5 , which is consistent with our experimental results [ 1 , 23 ]. At 4 h, the expression of Cchsf decreased again, suggesting that HSF transcriptional activity is weakened somewhat over time [ 19 , 43 ].…”

“…C. suppressalis and C. chilonis were collected from a suburb of Yangzhou (32.39 °N, 119.42 °E) and reared under the laboratory conditions at 27 ± 1 °C, 60–70% RH and a 16:8 h (light/dark) photoperiod [ 2 ]. C. suppressalis larvae were reared on an artificial diet [ 1 ]. C. chilonis adults were supplied with a 10% honey/water solution and propagated using 5th instar larvae of C. suppressalis as hosts.…”

“…Chilo suppressalis (Walker) is a detrimental rice pest that widely distributed in rice fields of China, which is known as the striped rice stem borer [ 1 ]. Cotesia chilonis (Munakata) is the major endoparasitoid of Chilo suppressalis (Walker), and has become the dominant parasitic wasp of C. suppressalis as global temperatures have risen [ 2 , 3 , 4 ].…”

“…Many studies demonstrated that various sHSPs play a significant part in thermotolerance of insects [ 1 , 2 , 27 ]. Our previous studies have shown that Cc HSPs play an important role in temperature tolerance; however, with the exception of Cchsp40 , there is no evidence for the role of sHSPs in thermotolerance of C. chilonis [ 2 , 27 ].…”

Comparison of morphology, development and expression patterns of hsf and hsp11.0 of Cotesia chilonis under normal and high temperature

“…Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) is a detrimental rice pest in southern Europe, northern Africa and widely distributed in China and other Asian countries ( Lu et al, 2013 ; Luo et al, 2014 ). Issues of pesticide residues, environmental pollution and pesticide poisoning have attracted the attention and stimulated the explore on new biological control methodologies such as the use of natural enemies ( He et al, 2013 ; Hong, 2015 ; Gao et al, 2019 ). Cotesia chilonis (Munakata) is the dominant parasitoid of C. suppressalis and occurs in southeastern and eastern Asia, regions where it has value as a biological control agent for C. suppressalis ( Huang, Wu & Ye, 2011 ; Wu et al, 2013 ; Pan et al, 2018 ) .…”