## 3 Results
### Validation of Genes Related to Abscisic Acid Metabolism and Signaling  
In the abscisic acid metabolism and signaling pathway, the expression levels of 8 genes including 9_-cis-epoxy carotenoid dioxygenase_ (Unigene21708_All), _violaxanthin de-epoxidase_ (CL3990.Contig2_All), _xanthoxin dehydrogenase_ (Unigene30770_All), _beta-carotene hydroxylase_ (Unigene15097_All), _abscisic acid 8_-_hydroxylase_ (CL9408.Contig2_All), _ABA responsive element binding factor_ (CL3543.Contig1_All), _abscisic acid receptor PYL4-like_ (Unigene19549_All), and _protein phosphatase 2C_ (CL3509.Contig2_All) were detected by qRT-PCR (Figure 5). In the leaves, the transcript levels of these genes were correlated well with the digital gene expression patterns (Tables S1 and S2). The two genes, Unigene21708_All and CL3543.Contig1_All, both possessed the highest and lowest expression at 4 and 12 h after simulated drought stress, respectively. Transcription of _violaxanthin de-epoxidase_ did not change significantly after treatment for 4 h, followed by a downward trend afterwards. The gene, Unigene3077_All, encoding xanthoxin dehydrogenase, showed a continuous rise in mRNA abundance during salt treatment, whereas expression patterns of Unigene 15097_All and CL9408.Contig2_All were completely the opposite. Unigen19549_All exhibited a downward trend in transcript levels during treatment for 4 h. CL3509.Contig2_All was highly expressed at 4 and 12 h after treatment. In the cloves, Unigene21708_All and CL3509.Contig2_All were highly expressed after treatment for 4 h, whereas CL3990.Contig2_All, Unigene 30770_All, and Unigene 19549_All showed higher mRNA abundance after treatment for 1 h. Unigene 15097_All displayed the highest and lowest expression at 12 and 4 h after treatment, respectively. CL9408.Contig2_All remained relatively stable expression during the first three stages of treatment, followed  
Figure 3: Distribution of the differentially expressed genes between drought-stressed samples. (**a**) Volcano plot of DEGs between D0 and D1 samples. (**b**) Volcano plot of DEGs between D0 and D4 samples. (**c**) Volcano plot of DEGs between D0 and D12 samples. (**d**) Volcano plot of DEGs between D1 and D4 samples. (**e**) Volcano plot of DEGs between D1 and D12 samples. (**f**) Volcano plot of DEGs between D4 and D12 samples.  
by a sharp increase after treatment for 12 h. Salt treatment significantly reduced the transcript levels of CL3543.Contig1_All. In the roots, Unigene21708_All, Unigene15097, and Unigene19549_All were highly expressed in the plants without treatment, whereas CL9408.Contig2_All and CL3509.Contig2_All showed the highest expression after treatment for 12 h. CL3990.Contig2_All and CL3543.Contig1_All were highly expressed at 4 h after treatment. Transcription of Unigene30770_All increased initially, followed by a decrease (Figure 5).  
Figure 4: KEGG enrichment of differentially expressed genes under drought conditions. The \(y\)-axis represents the KEGG pathway, and the \(x\)-axis represents the enrichment factor. A high q-value is expressed by light blue, whereas a low q-value is represented by dark blue.  
Figure 5: Expression patterns of eight genes involved in abscisic acid metabolism and signaling in garlic samples subjected to drought stress. Genes implicated in abscisic acid metabolism and signaling  
pathway include (**a**) 9-cis-epoxycarotonoid dioxygenase (Unigene21708_All), (**b**) violaxanthin deepoxidase (CL3990.Contig2_All), (**c**) xanthoxin dehydrogenase (Unigene3070_All), (**d**) beta-carotene hydroxylase (Unigene15097_All), (**e**) abscisic acid 8\({}^{\prime}\)-hydroxylase (CL9408.Contig2_All), (**f**) ABA responsive element binding factor (CL3543. Contig1_All), (**g**) abscisic acid receptor PYL4-like (Unigene19549_All), and (**h**) protein phosphatase 2C (CL3509.Contig2_All). The different lowercase letters in the same tissue represent a significant difference at the 0.05 level.