Identification of important TFs downstream ofAT5G08670-dependent signaling
Differentially expressed genes of transcription factors were ordered
into up-regulated and down-regulated groups. Venn diagrams were plotted
for the 3 groups of up-regulated transcription factors. The results
showed that there were 5 up-regulated genes in WT, SALK_047877 ,SALK_083115, and 56 up-regulated genes in the WT only (Figure
9a, Table S1). Venn diagrams were performed for the three groups of
down-regulated genes. The results showed that there were 16
down-regulated genes in WT, SALK_047877 , SALK_083115 ,
and 71 down-regulated genes in the WT only (Figure 9b, Table S2). Based
on differently expressed TFs, we constructed a regulatory network of TFs
to characterize the downstream network associated withAT5G08670 -dependent signaling. Analysis of the protein-protein
interaction network revealed that ETT , PTF1 , TCP2 ,
and KTF1 play key regulatory roles in AT5G08670 -dependent
signaling (Figure 9c). ETT1 is located in mitochondria and plays
a role in protecting mitochondrial components such as DNA from oxidative
injury resulting from the generation of superoxide by the mitochondria
(Paul & Snyder, 2010). Furthermore, plastid transcription 1
(PTF1 ) is involved in plastid protein synthesis and acts as a TF
of PSBD that encodes protein D2 of PSII (Baba, Nakano, &
Yoshida, 2001; Kim M, 1995). TCP2 positively regulates mRNA
expression of HY5-HOMOLOG (HYH ) (He, Zhao, Kong, Zuo, &
Liu, 2016), which is a photomorphogenesis-mediated transcription factor
(Holm, Ma, Qu, & Deng, 2002). These findings indicate thatAT5G08670 -dependent signaling might involve specific TFs in
mitochondria, chloroplasts, and nuclei to regulate plastid retrograde
signaling.