Mutations in the tomato gibberellin receptors suppress xylem proliferation and reduce water loss under water-deficit conditions

Natanella Illouz-Eliaz, Idan Nissan, Ido Nir, Uria Ramon, Hagai Shohat, David Weiss*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Low gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. This leads to lower transpiration and improved water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole-plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessel proliferation, which led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms: it reduces leaf area, promotes stomatal closure, and reduces xylem proliferation and expansion, and as a result, xylem hydraulic conductance. We further examined if gid1a performs better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited a higher harvest index.

Original languageAmerican English
Pages (from-to)3603-3612
Number of pages10
JournalJournal of Experimental Botany
Volume71
Issue number12
DOIs
StatePublished - 22 Jun 2020

Bibliographical note

Publisher Copyright:
© 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Keywords

  • CRISPR-Cas9
  • GID1 receptors
  • drought
  • gibberellin
  • hydraulic conductance, tomato (Solanum lycopersicum)
  • transpiration
  • xylem

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