Table 1.
Specific primers for quantitative real-time PCR.
Table 2.
Transcripts encoding for sucrose synthase in three citrus genome databases and their pairwise identities.
Figure 1.
Schematic representation of the six Sus gene structures in citrus.
Boxes indicate exons and single lines between the boxes indicate introns. The numbers on boxes and down lines indicate the length of the exon and intron, respectively. Sus I, II and III refer to the three groups of Sus genes family shown in Figure 2.
Figure 2.
Phylogenetic analysis of citrus and other plant Sus homologs.
The phylogenetic tree was constructed by the MEGA 4.0 program with the neighbor-joining method. Sus accession numbers are listed in Table S2. The black triangle shows the position of six citrus Sus isoforms. The white triangle shows the position of three c. unshiu Sus isoforms reported by Komatsu et al. [20].
Figure 3.
Relative transcript levels of six citrus Sus genes in different citrus tissues or organs.
The expression levels of the six citrus Sus genes were measured by real-time qRT-PCR and standardized by actin gene expression level. The total RNA was extracted from early leaf (EL), mature leaf (ML), flower (FL) and fruit juice sacs (JS) (details in Materials and Methods). All qRT-PCR values are the average ±Se of three replicates. Bars marked with lower-case letters indicate that the expression levels showed significant difference at P<0.05 by using Duncan's test.
Figure 4.
Relative transcript levels of CitSus1-6 in fruit juice sacs (JS) and segment membrane(SM) at 106 and 165 days after anthesis.
A-F refer to the transcript levels of CitSus1-6 genes, respectively. qRT-PCR values are the average ±Se of three replicates. Bars marked with lower-case letters indicate that the gene expression levels showed significant difference at P<0.05 by using Duncan's test.
Figure 5.
Relative transcript levels of CitSus1-6 in mature leaves in response to dehydration (A) and in fruit segment membrane (B) and juice sacs (C) in response to mild drought stress.
Bars marked with lower-case letters indicate that the expression levels showed significant difference at P<0.05 by using Duncan's test. Asterisk (*) on bars indicates the gene expression levels showed significant difference between film mulch and the control at P<0.05 by using t-test (LSD). In the present study, film mulch decreased the soil water content creating a mild drought stress compared with the control.