APETALA2 control of barley internode elongation

Vrushali Patil, Hannah I. McDermott, Trisha Mcallister, Michael Cummins, Joana Clara Silva, Ewan Mollison, Rowan Meikle, Jenny A. Morris, Pete E. Hedley, Robbie Waugh, Christoph Dockter, Mats Hansson, Sarah McKim (Lead / Corresponding author)

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Abstract

Many plants dramatically elongate their stems during flowering, yet how this response is coordinated with the reproductive phase is unclear. We demonstrate that microRNA (miRNA) control of APETALA2 (AP2) is required for rapid, complete elongation of stem internodes in barley, especially of the final 'peduncle' internode directly underneath the inflorescence. Disrupted miR172 targeting of AP2 in the Zeo1.b barley mutant caused lower mitotic activity, delayed growth dynamics and premature lignification in the peduncle leading to fewer and shorter cells. Stage- and tissue-specific comparative transcriptomics between Zeo1.b and its parent cultivar showed reduced expression of proliferation-associated genes, ectopic expression of maturation-related genes and persistent, elevated expression of genes associated with jasmonate and stress responses. We further show that applying methyl jasmonate (MeJA) phenocopied the stem elongation of Zeo1.b, and that Zeo1.b itself was hypersensitive to inhibition by MeJA but less responsive to promotion by gibberellin. Taken together, we propose that miR172-mediated restriction of AP2 may modulate the jasmonate pathway to facilitate gibberellin-promoted stem growth during flowering.

Original languageEnglish
Article number170373
Pages (from-to)1-16
Number of pages16
JournalDevelopment
Volume146
Issue number11
Early online date10 May 2019
DOIs
Publication statusPublished - 12 Jun 2019

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Keywords

  • APETALA2
  • Cereal development
  • Intercalary meristem
  • Jasmonate
  • Phase change
  • Stem elongation

Cite this

Patil, V., McDermott, H. I., Mcallister, T., Cummins, M., Clara Silva, J., Mollison, E., Meikle, R., Morris, J. A., Hedley, P. E., Waugh, R., Dockter, C., Hansson, M., & McKim, S. (2019). APETALA2 control of barley internode elongation. Development, 146(11), 1-16. [170373]. https://doi.org/10.1242/dev.170373