Fig. 2

SlIPT4 knockdown in tomato induced leaf senescence. a and b The phenotype of accelerated leaf senescence in SlIPT4-RNAi lines. Most leaves withered and abscised at 8-week-old plants (a), and leaves at expanded mature stage became yellow color (b). c SlIPT4 silencing efficiency was confirmed by qRT-PCR. d and e Relative expression levels of senescence marker genes, SAG12 and WRKY53, were tested by qRT-PCR. f Obvious reduction of total chlorophyll in expanded leaves of SlIPT4-RNAi lines as shown in b. Biological replicates were performed in triplicate, and the data are shown as mean ± SE. g and h and i Relative expression levels of GLK2, SGR, and Rbcs3A (regulating chlorophyll biosynthesis, chlorophyll degradation, and photosynthetic rate, respectively) were tested by qRT-PCR. For qRT-PCR, data are expressed as relative values based on the values of the control wild-type (WT) taken as reference sample set to 1. Each value represents mean ± SE of three replicates. Asterisks represent significant differences between SlIPT4-RNAi line and wild-type control (*P < 0.05, **P < 0.01, Student’s t test)