Figure 1.
Symptoms shown by paulownia when infected with PaWB Phytoplasma.
(A) a healthy branch of paulownia in the field; (B) symptoms shown by a branch infected with PaWB Phytoplasma in the field; (C) a healthy branch of paulownia grown in the culture medium and (D) symptoms shown by a branch infected with PaWB Phytoplasma when grown in the culture medium.
Figure 2.
Distribution of unigene sizes.
Figure 3.
Unigenes aligned to the COG database can be classified functionally into 25 molecular families.
Figure 4.
Best hits were aligned to the GO database and transcripts were assigned to at least one GO term. Most unigenes were grouped into three major functional categories, namely biological processes, cellular components, and molecular functions.
Figure 5.
Relationship between DEGs in the two groups (A) and cluster analysis of the common DEGs found in the two groups (B).
Figure 6.
Validation of relative expression levels of the transcripts selected from the DGE analysis results using quantitative RT-PCR (qRT-PCR).
Expression profiles of the seven selected genes were determined by qRT-PCR (Blue) and DGE (Red). The signal intensity of each transcript was normalized using actin. The predicted function of each gene is shown in Table 5. The error bars represent the standard deviations of the qRT-PCR signals from each of the three independent samples.
Figure 7.
A model for cytokinin (CK) and abscisic acid (ABA) biosynthesis in paulownia infected with PaWB Phytoplasma.
In plants, CKs are synthesized mainly through two pathways, namely cis-zeatin (cZ) biosynthesis and trans-zeatin (tZ) biosynthesis. Dimethylallyl diphosphate (DMAPP) is the common substrate for both pathways and is formed through isomerization of isopentenyl diphosphate (IPP), catalyzed by isopentenyl diphosphate isomerase (IPI).. Trans-zeatin biosynthesis, which is the main pathway for cytokinin synthesis in most plants, produces isopentenyladenine (iP)-type and tZ-type CKs. Adenylate isopentenyltransferases (IPT) catalyze the reaction between DMAPP and AMP/ADP/ATP to produce iP-nucleotides, which are then converted to tZ-nucleotides by cytokinin trans-hydroxylase (CYP735A). For ABA biosynthesis, farnesyl diphosphate synthase (FPS) catalyzes the synthesis of the isoprenoid precursors from both IPP and DMAPP and xanthoxin dehydrogenase (XD) catalyzes the last step in ABA formation. The up-regulated and down-regulated genes in paulownia after PaWB Phytoplasma infection are indicated in red and green, respectively. cZR: cZ riboside, GPP: geranyl diphosphate, FPP: farnesyl-diphosphate; iPRTP: iP riboside 5′-triphosphate; iPRDP: iP riboside 5′-diphosphate; iPRMP: iP riboside 5′-monophosphate; iPR: iP riboside; tZRTP: tZ riboside 5′-triphosphate; tZRDP: tZ riboside 5′-diphosphate; tZRMP: tZ riboside 5′-monophosphate; tZR: tZ riboside.