Plant height heterosis is quantitatively associated with expression levels of plastid ribosomal proteins

Devon Birdseye, Laura A. De Boer, Hua Bai, Peng Zhou, Zhouxin Shen, Eric A. Schmelz, Nathan M. Springer, Steven P. Briggs

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The use of hybrids is widespread in agriculture, yet the molecular basis for hybrid vigor (heterosis) remains obscure. To identify molecular components that may contribute to trait heterosis, we analyzed paired proteomic and transcriptomic data from seedling leaf and mature leaf blade tissues of maize hybrids and their inbred parents. Nuclear- and plastid-encoded subunits of complexes required for protein synthesis in the chloroplast and for the light reactions of photosynthesis were expressed above midparent and high-parent levels, respectively. Consistent with previous reports in Arabidopsis, ethylene biosynthetic enzymes were expressed below midparent levels in the hybrids, suggesting a conserved mechanism for heterosis between monocots and dicots. The ethylene biosynthesis mutant, acs2/acs6, largely phenocopied the hybrid proteome, indicating that a reduction in ethylene biosynthesis may mediate the differences between inbreds and their hybrids. To rank the relevance of expression differences to trait heterosis, we compared seedling leaf protein levels to the adult plant height of 15 hybrids. Hybrid/midparent expression ratios were most positively correlated with hybrid/midparent plant height ratios for the chloroplast ribosomal proteins. Our results show that increased expression of chloroplast ribosomal proteins in hybrid seedling leaves is mediated by reduced expression of ethylene biosynthetic enzymes and that the degree of their overexpression in seedlings can quantitatively predict adult trait heterosis.

Original languageEnglish (US)
Article numbere2109332118
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number47
StatePublished - Nov 23 2021

Bibliographical note

Funding Information:
ACKNOWLEDGMENTS. This material is based upon work supported by NSF Grant 1546899 (to S.P.B. and N.M.S.) and an NSF Graduate Research Fellowship under Grant DGE-1650112 (to D.B.). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF.

Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.


  • Ethylene
  • Heterosis
  • Hybrid vigor
  • Maize
  • Proteomics

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.


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