## 2 Results
### GO Enrichment Analysis of the DEGs  
To investigate the functions of the DEGs detected in the _P. acerifolia_ response to _C. ciliata_ feeding, we analyzed the DEGs by Gene Ontology (GO) term enrichment. For the 24 h treatment, the significantly enriched GO terms in the DEGs, 159 GO terms were significantly enriched, the ten most significant terms were: oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen (GO:0016702), dioxygenase activity  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Sample** & **Raw Bases** & **Clean Bases** & **Q20 (\%)** & **Q30 (\%)** \\ \hline T24h\_2 & \(7.55\times 10^{9}\) & \(7.40\times 10^{9}\) & 98.13 & 94.20 \\ \hline T24h\_3 & \(8.15\times 10^{9}\) & \(7.97\times 10^{9}\) & 97.99 & 93.87 \\ \hline T48h\_1 & \(8.41\times 10^{9}\) & \(8.23\times 10^{9}\) & 97.92 & 93.70 \\ \hline T48h\_2 & \(8.09\times 10^{9}\) & \(7.90\times 10^{9}\) & 97.84 & 93.52 \\ \hline T48h\_3 & \(7.92\times 10^{9}\) & \(7.75\times 10^{9}\) & 98.14 & 94.21 \\ \hline \end{tabular}
\end{table}
Table 1: _Cont._  
Figure 1: Venn diagram showing the DEGs in _P. acerifolia_ leaves in response to _C. ciliata_ damage after 24 and 48 h of feeding.  
(GO:0051213), monocarboxylic acid biosynthetic process (GO:0072330), lipid biosynthetic process (GO:0008610), terpene synthase activity (GO:0010333), fatty acid metabolic process (GO:0006631), organic acid biosynthetic process (GO:0016053), carboxylic acid biosynthetic process (GO:0046394), monooxygenase activity (GO:0004497), heme binding (GO:0020037) (Table S1 and Figure S1). In the 48 h treatment, 187 GO terms were significantly enriched, the 10 most significant terms were: protein-chromophore linkage (GO:0018298), cell wall (GO:0005618), external encapsulating structure (GO:0030312), glucosamine-containing compound catabolic process (GO:1901072), glucosamine-containing compound metabolic process (GO:1901071), chitin metabolic process (GO:0006030), amino sugar catabolic process (GO:0046348), chitin catabolic process (GO:0006032), aminoglycan metabolic process (GO:0006022), aminoglycan catabolic process (GO:0006026) (Table S2 and Figure S2). Also, for the 303 unigenes that were up-regulated at both time points, 86 GO terms were significantly enriched, the ten most significant terms were: carbon-oxygen lyase activity, acting on phosphates (GO:0016838), monocarboxylic acid biosynthetic process (GO:0072330), magnesium binding (GO:0000287), oxylipin biosynthetic process (GO:0031408), oxylipin metabolic process (GO:0031407), monooxygenase activity (GO:0004497), oxidoreductase activeity, acting on paired donors, with incorporation or reduction of molecular oxygen (GO:0016705), single-organism catabolic process (GO:0044712), oxidoreductase activeity, acting on single donors with incorporation of molecular oxygen (GO:0016701), dioxygenase activity (GO:0051213) (Table S3 and Figure 2).  
Figure 2: Top ten GO terms that were enriched in the 303 unigenes that were up-regulated at both time points. The x-axis represents the GO term and the y-axis represents the enrichment ratio (the number of unigenes annotated to a GO term in a gene set divided by the number of unigenes annotated to this GO term in the entire unigenes as background set.) The color indicates the significance of the enrichment. \({}^{***}\) mean False Discovery Rate \(<\)0.001.