Fox transcription factor AccGRF1 in response to glyphosate stress in Apis cerana cerana.

Glyphosate is an herbicide commonly used in agriculture, and its widespread use has adversely affected the survival of nontarget organisms. Among these organisms, bees in particular are important pollinators, and declining bee populations have severely affected crop yields around the world. However, the molecular mechanism by which glyphosate harms bees remains unclear. In our experiment, we screened and cloned a glyphosate-induced gene in Apis cerana cerana (A. c. cerana) and named glyphosate response factor 1 (AccGRF1). Sequence analysis showed that AccGRF1 contains a winged-helix DNA binding domain, which suggests that it belongs to the Forkhead box (Fox) protein family. qRT-PCR and heterologous expression in Escherichia coli and yeast showed that AccGRF1 can respond to glyphosate and oxidative stress. After AccGRF1 knockdown by means of RNA interference (RNAi), the resistance of A. c. cerana to glyphosate stress improved. The results suggested that AccGRF1 is involved in A. c. cerana glyphosate stress tolerance. This study reveals the functions of Fox transcription factors in response to glyphosate stress and provides molecular insights into the regulation of glyphosate responses in honeybees.

Role of c-Jun NH2 -terminal kinase-mediated mitogen-activated protein kinase pathway in response to pesticides in Apis cerana cerana.

The mitogen-activated protein kinase (MAPK) cascade pathway plays an important role in regulating stress responses. The function of the c-Jun NH2 -terminal kinase (JNK), a component of the MAPK cascade pathway, in Apis cerana cerana (Acc) remains unclear. Here, JNK was isolated and identified from Acc. Bioinformatics analyses revealed there is a typical serine/threonine protein kinase catalytic domain in the AccJNK protein. An expression profile analysis showed that AccJNK was significantly induced by pesticide treatments. To further explore the functional mechanisms of AccJNK, a yeast 2-hybrid screen was performed, activator protein-1 (AP-1) was screened as the interaction partner of AccJNK, and the interaction relationship was further verified by pull-down assay. Quantitative real-time polymerase chain reaction showed the expression pattern of AccAP-1 was similar to that of AccJNK. After a knockdown of AccJNK or AccAP-1 by RNA interference, the survival rate of Acc after pesticide treatments increased. Additionally, the expression levels of antioxidant-related genes and the activities of antioxidant enzymes increased, suggesting that the knockdown of AccJNK or AccAP-1 increased the antioxidant capacity of bees. Our study revealed that the JNK-mediated MAPK pathway responds to pesticide stress by altering the antioxidant capacity of Acc.