3.4 | Fatty acid related genes under drought stress inPse. libanotica
To the identify candidate genetic regions associated with fatty acids
and their derivatives metabolism pathway, we performed 28 d drought
stress treatment without irrigation and conducted transcriptome
sequencing on each treatment. Every seven days was taken as a treatment
7 d, 14 d, 21 d, 28 d, and each treatment has three biology repeats. In
total, 1,007 differentially expressed genes (DEGs) were shared at four
treatments (Figure S6). Differential genes were largely expressed at 14
d drought treatment. Gene Ontology (GO) enrichment analysis showed that
1,190 GO terms were assigned to the 2,300 DEGs that responded to drought
treatment (Figure S7). KEGG enrichment analysis showed that DEGs were
mainly involved in biosynthesis of unsaturated fatty acids, fatty acid
metabolism and elongation process (Figure S8). Comparing the DEGs with
expansion and contraction genes, 1,576 DEGs (9.25%) were found in the
expansion genes, whereas 61 DEGs (29.35%) were found in the contraction
genes.
In total, we identified 14 significantly different expression genes
including 20 transcripts which directedly participated in fatty acid
biosynthesis under drought stress (Figure 3). In fatty acid biosynthesis
pathway of Pse. libanotica , the Acc and Fatb were
upregulated during 21 day’s water deficit. Except for two transcripts ofKcs5 and a transcript evm.TU.CTG175.54 , other genesKcs1 , Kcs6 , Kcs11 , Kcs12 , and Kcs20were significantly downregulated. Genes catalyzed VCLFAs derivatives in
alcohol-forming pathway (Far , Far1 and Far4 ) and
alkane-forming pathway (Cer1 , Cer3 /Cytb5 ,Cyp96a15 /Mah1 ) were upregulated apart from one of theFar1 transcript-evm.TU.CTG5611.2 . In summary, onlyKcs5 and evm.TU.CTG175.54 were responsible for VCLFA
elongation in Pse. libanotica .