Figure Legends
Figure 1. SlmiR-168a and SlAGO1 expression profiles in JZ18 and JZ34 plants under normal K+conditions and K+ deficiency conditions. Samples were collected at 0, 1, 3, 5, and 7 days after treatment. a. JZ18 seedlings under normal K+ conditions; b. JZ18 seedlings under K+ deficiency conditions; c. JZ34 seedlings under normal K+ conditions; d. JZ34 seedlings under K+ deficiency conditions. CK: normal K+ (4 mM); LK: K+ deficiency (0.5 mM). The experiments were repeated three times. *P < 0.05 compared with the control.
Figure 2. SlmiR-168a and SlAGO1 expression profiles in different tomato tissues. The experiments were repeated three times. *P < 0.05 compared with the control.
Figure 3. Mutant SlAGO1 transgenic transcripts were resistant to SlmiR-168a -mediated cleavage in tomatoes. a. Representation of the constructs used for transgenic expression of theSlmiR-168a -resistant mutant (rSlAGO1 ) in tomatoes. Mutations were introduced at four locations, and these base changes did not affect the native protein sequence. b. Amplification of therSlAGO1 cDNA band located at 3100 bp. c. Amplification of thepre-SlmiR-168a band at 159 bp.
Figure 4. Comparison of morphological changes in WT,35S:SlmiR-168a , and 35S:rSlAGO1 plants under normal K+ conditions and K+ deficiency stress after 7 days. a. Changes in the root hair region in WT,35S:SlmiR-168a , and 35S:rSlAGO1 plants under CK and LK conditions after 7 days (100×magnification). b. Differences in leaflet states in WT, 35S:SlmiR-168a , and 35S:rSlAGO1 plants under CK and LK conditions after 7 days. c. Root-shoot ratios in WT,35S:SlmiR-168a , and 35S:rSlAGO1 plants under CK and LK conditions after 7 days. d. Chlorophyll contents of WT,35S:SlmiR-168a , and 35S:rSlAGO1 plants under CK and LK conditions after 7 days. e. K+ contents in WT,35S:SlmiR-168a , and 35S:rSlAGO1 plants under CK and LK conditions after 3 and 7 days. CK: normal K+ (4 mM); LK: K+ deficiency (0.5 mM).
Figure 5. The identified miRNAs from WT, 35S:SlmiR-168a , and 35S:rSlAGO1 plants. a. Length distribution of total identified miRNAs. b. Number of miRNAs in 35S:rSlAGO1 plants compared with WT and 35S:SlmiR-168a plants compared with WT.P < 0.05, 0.01, or 0.001.
Figure 6. a. GO analysis of predicted targets of 107 differentially expressed miRNAs (20 terms). b. KEGG pathway enrichment analyses of predicted targets of 107 differentially expressed miRNAs (20 pathways).
Figure 7. Quantitative real-time PCR validation of seven differentially expressed miRNAs in low K+ sensitive JZ18 tomatoes and low K+ tolerant JZ34 tomatoes under normal conditions and K+ deficiency stress. K+: normal K+ (4 mM); K-: K+ deficiency (0.5 mM). The experiments were repeated three times.
Figure 8. Comparison of CTK and ABA contents in low K+ sensitive and low K+ tolerant tomatoes under K+ deficiency stress conditions after 24 h, 3 days, and 7 days. CK: normal K+ (4 mM); LK: K+ deficiency (0.5 mM). The experiments were repeated three times. *P < 0.05.
Figure 9. Hypothetical model of the molecular mechanisms through which SlmiR-168a -mediated SlAGO1 regulates the K+ deficiency stress response. SlAGO1 regulated by SlmiR-168a may be involved in various processes, including root growth, the CTK signalling pathway, and the ABA signalling pathway, by influencing the regulatory pathways of other miRNAs (e.g.,ath-miR-171a , stu-miR-530 , stu-miR-0384 ,ppe-miR-858 , stu-miR-8007b , and PC-3p-276756_24 ).