Figure 3.

Diverse miR7122-TAS(L)-PPR-siRNA Pathways Identified.

Four categories of miR7122-TAS(L)-PPR-siRNA pathways identified in nine plants are summarized. The dotted arc around the “PPR” represents the ability of processing secondary siRNAs. The length of trigger sRNA is indicated near the arrows. Category I: In peach and strawberry, PPR phasiRNA production was triggered by ppe-miR7122 and fve-PPRtri1/2, respectively, through direct targeting or the intermediation of TASL genes. Category II: In Arabidopsis and citrus, PPR phasiRNA generation was triggered by miR173 and csi-miR7122, respectively, through the intermediation of TAS(L) genes or by directly targeting of other miRNAs. Category III: In apple, tobacco, and grape, PPR siRNA production was triggered by miR7122 solely through the intermediation of TASL genes. Category IV: In soybean and M. truncatula, PPR phasiRNA generation was triggered by miR1509 through one or two layers of TASL–tasiRNA interactions or by direct targeting of gma-miR1508 in soybean as well.