PT  - JOURNAL ARTICLE
AU  - Devon Birdseye
AU  - Laura A. de Boer
AU  - Hua Bai
AU  - Peng Zhou
AU  - Zhouxin Shen
AU  - Eric A. Schmelz
AU  - Nathan M. Springer
AU  - Steven P. Briggs
TI  - Plant trait heterosis is quantitatively associated with expression heterosis of the plastid ribosomal proteins
AID  - 10.1101/2021.02.16.431485
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.16.431485
4099  - http://biorxiv.org/content/early/2021/02/22/2021.02.16.431485.short
4100  - http://biorxiv.org/content/early/2021/02/22/2021.02.16.431485.full
AB  - 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 the known higher photosynthetic capacity of maize hybrids, we generated paired datasets of the proteomes and transcriptomes from leaf tissues of maize hybrids and their inbred parents. Expression patterns in the hybrids were semi-dominant to overdominant for subunits of the digenomic protein complexes required for the light reactions of photosynthesis and for chloroplast protein synthesis; nuclear and plastid-encoded subunits were elevated similarly. These patterns were not mirrored in the nuclear transcriptomes. We compared growth to transcript and protein levels of multiple hybrids with varying levels of heterosis. Expression heterosis (hybrid/mid-parent expression levels) of chloroplast ribosomal proteins and of nuclear transcripts for the photosynthetic light reactions was positively correlated with plant height heterosis (hybrid/mid-parent plant height). Ethylene biosynthetic enzymes were expressed below mid-parent levels in the hybrids, and the ethylene biosynthesis mutant acs2/acs6 partially phenocopied the hybrid proteome, indicating that a reduction in ethylene biosynthesis may be upstream of the elevated expression of photosynthetic and ribosomal proteins in chloroplasts of hybrids.Competing Interest StatementThe authors have declared no competing interest.