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Patterning the Arabidopsis fruit

Patterning the Arabidopsis fruit. Arabidopsis fruit structure. valve margin. valve. replum. Arabidopsis fruit opening. valve margin. seed. valve. replum. Fruit dehiscence promotes seed dispersal. valve. valve.

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Patterning the Arabidopsis fruit

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  1. Patterning the Arabidopsis fruit

  2. Arabidopsis fruit structure valve margin valve replum

  3. Arabidopsis fruit opening valve margin seed valve replum

  4. Fruit dehiscence promotes seed dispersal valve valve

  5. Genes involved in seed dispersal in Arabidopsis can control loss of yield in oilseed crops

  6. Note that DZ = Valve Margin

  7. Genes Controlling Fruit Development ? ? ? replum valve margin valve

  8. SHATTERPROOF (SHP) gene is required for valve margin formation wild type shp

  9. Genes Controlling Fruit Development ? SHP ? replum valve margin valve

  10. IND andSHP are required for valve margin formation wild type ind shp

  11. replum IND is expressed in stripes at the valve margin and is positively regulated by SHP valve margin valve wild type shp

  12. Genes Controlling Fruit Development SHP ? IND ? replum valve margin valve

  13. How is SHP and IND expressionlimited to the valve margin? SHP IND ? ? replum valve margin valve

  14. FRUITFULL (FUL) transcription factor is required for valve cells Valve cells ful wild type FUL is expressed in valve cells ful wild type

  15. SHP and IND are ectopically expressed in ful mutant valves valve Wild type valve ful mutant IND expression

  16. SHP and IND are negatively regulatedby FUL in the valves Wild type ful mutant IND expression

  17. Is the fruitfull mutant phenotype caused by ectopic expression of the valve margin (SHP, IND) genes?

  18. The failure of ful-mutant fruit to elongate is restored by mutations in shp and ind Wild type shp ind ful ind1 ful shp ful ful

  19. The fruitfull mutant phenotype is caused by mis-expression of SHP and IND Wild type shp ind ful ind ful shp ful ful “Valve” is the “default” state

  20. FUL is expressed in valve cells where it functions to negatively regulate SHP and IND SHP IND ? FUL replum valve margin valve enb

  21. replumless (rpl) mutant fails to form a replum Wild type rpl replum

  22. RPL encodes a homeobox protein and is expressed in the replum RPL

  23. Are SHP and IND ectopically expressed in the rpl mutant replum?

  24. IND is ectopically expressedin the rpl mutant replum VM VM R wild type rpl mutant IND expression

  25. Is the replumless mutant phenotypecaused by the ectopic expressionof the valve margin genes?

  26. Mutations in SHP rescue rpl Wild type rpl rpl shp

  27. RPL is expressed in the replum and functions to negatively regulated SHP and IND SHP IND FUL RPL replum valve margin valve

  28. What happens in the ful rpl double mutant? SHP IND FUL RPL replum valve margin valve

  29. All valve margin: rpl ful replum valve valve SHP and IND are expressed In the valve, valve margin and replum regions in rpl ful mutants rpl ful

  30. Genes controlling fruit development? SHP IND FUL RPL replum valve margin valve

  31. replum valve wild type The FUL gene is normally expressed in valves What happens if the FUL gene is mis-expressed in all cells of the fruit?

  32. mis-expression of FRUITFULL converts replum and valve margin cells into valve cells replum valve wild type 35S::FUL

  33. Ap -> Notch -> Wing Margin Loss of ap in Dorsal Cells = D/V Organizer -> Margin Formation D/V Organizer -> Margin Formation and Wing Growth Activation of Notch Along Future Margin D/V Signaling Is Required for Wing Margin Formation and Wing Outgrowth ap - cells ap Expressing Cells D D ->V Signal V V -> D Signal ap Non-expressing Cells Adult wing with ap - patch Wing imaginal disc in larva Adult wing (viewed end on) Fig. 4.4

  34. Interactions between cells on the dorsal and ventral • surfaces of leaves result in the formation of a leaf margin, • which is required for leaf outgrowth.

  35. Phantastica mutants, like apterous mutants in flies, cannot form the dorsal surface of leaves.

  36. Loss of phantastica function leads to loss of leaf outgrowth. • Partial loss of phantastica function leads to narrow leaves • that are cupped upwards due to fewer dorsal cells.

  37. Phantastica mutants illustrate that leaf outgrowth requires • interactions between dorsal and ventral cells.

  38. Weak phantastica mutants can have “islands” • of ventral cells on the dorsal surface. • Marginal structures form at the border between • dorsal and ventral cells.

  39. Conclusions • In flies and plants, juxtaposition of dorsal and ventral surfaces • induces formation of an organizing margin. • The organizing margin controls outgrowth of the appendage.

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