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Title: The YABBY gene SHATTERING1 controls activation rather than patterning of the abscission zone in Setaria viridis
Summary

Abscission is predetermined in specialized cell layers called the abscission zone (AZ) and activated by developmental or environmental signals. In the grass family, most identified AZ genes regulate AZ anatomy, which differs among lineages. A YABBY transcription factor,SHATTERING1(SH1), is a domestication gene regulating abscission in multiple cereals, including rice andSetaria. In rice,SH1inhibits lignification specifically in the AZ. However, the AZ ofSetariais nonlignified throughout, raising the question of howSH1functions in species without lignification.

Crispr‐Cas9 knockout mutants ofSH1were generated inSetaria viridisand characterized with histology, cell wall and auxin immunofluorescence, transmission electron microscopy, hormonal treatment and RNA‐Seq analysis.

Thesh1mutant lacks shattering, as expected. No differences in cell anatomy or cell wall components including lignin were observed betweensh1and the wild‐type (WT) until abscission occurs. Chloroplasts degenerated in the AZ of WT before abscission, but degeneration was suppressed by auxin treatment. Auxin distribution and expression of auxin‐related genes differed between WT andsh1, with the signal of an antibody to auxin detected in thesh1chloroplast.

SH1inSetariais required for activation of abscission through auxin signaling, which is not reported in other grass species.

 
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Award ID(s):
1938086
NSF-PAR ID:
10441964
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
New Phytologist
Volume:
240
Issue:
2
ISSN:
0028-646X
Format(s):
Medium: X Size: p. 846-862
Size(s):
["p. 846-862"]
Sponsoring Org:
National Science Foundation
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