The novel ethylene-responsive factor CsERF025 affects the development of fruit bending in cucumber
Overexpression of CsERF025 induces fruit bending by promoting the production of ethylene.
Cucumber fruit bending critically affects cucumber quality, but the mechanism that causes fruit bending remains unclear. To better understand this mechanism, we performed transcriptome analyses on tissues from the convex (C1) and concave (C2) sides of bending and straight (S) fruit at 2 days post anthesis (DPA). We identified a total of 281 differentially expressed genes (DEGs) from both the convex and concave sides of bent fruit that showed significantly different expression profiles relative to straight fruits. Of these 281 DEGs, 196 were up-regulated (C1/S_C2/S) and 85 were down-regulated (C1/S_C2/S). Among the 196 up-regulated DEGs, the transcriptional levels of genes related to ethylene biosynthesis and signaling pathways were significantly higher in bending fruit compared with straight fruit. CsERF025 showed the largest difference in expression between bending and straight fruit. CsERF025 is an AP2/ERF gene encoding a protein that localizes to the nucleus. Overexpression of this gene increased the bending rate of cucumber fruits and increased the angle of bending. CsERF025 increased both the expression of ethylene biosynthesis-related genes and the production of ethylene. The application of exogenous 1-aminocyclopropane-l-carboxylic acid (ACC) to straight fruits from control plants promoted fruit bending. Thus, CsERF025 enhances the production of ethylene and thereby promotes fruit bending in cucumber.
KeywordsCucumber Bending fruit Transcriptome CsERF025 Ethylene
This study was funded by the National Natural Science Foundation of China (31401863) and the Young Talents Project of Northeast Agricultural University (14QC12). There are no financial competing interests. We acknowledge Associate Professor Yongguang Li (Key Laboratory of Northeastern Soybean Biology and Genetic Breeding of the Ministry of Agriculture, China) for providing the pCXSN-1250 vector. We thank Professor Huazhong Ren (College of Agronomy and Biotechnology, China Agricultural University, Beijing), who provided the method for the genetic transformation of cucumber.
CW and ZQ designed and conceived the research, and CW, MX and XZ performed the experiments. CL, SL, DL and YX analyzed the sequencing data. CW wrote the entire manuscript, and ZQ edited the manuscript.
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