GNI-A1 mediates trade-off between grain number and grain weight in tetraploid wheat

Guy Golan, Idan Ayalon, Aviad Perry, Gil Zimran, Toluwanimi Ade-Ajayi, Assaf Mosquna, Assaf Distelfeld, Zvi Peleg

Research output: Contribution to journalArticlepeer-review

Abstract

Key message: Wild emmer allele of GNI-A1 ease competition among developing grains through the suppression of floret fertility and increase grain weight in tetraploid wheat. Abstract: Grain yield is a highly polygenic trait determined by the number of grains per unit area, as well as by grain weight. In wheat, grain number and grain weight are usually negatively correlated. Yet, the genetic basis underlying trade-off between the two is mostly unknown. Here, we fine-mapped a grain weight QTL using wild emmer introgressions in a durum wheat background and showed that grain weight is associated with the GNI-A1 gene, a regulator of floret fertility. In-depth characterization of grain number and grain weight indicated that suppression of distal florets by the wild emmer GNI-A1 allele increases weight of proximal grains in basal and central spikelets due to alteration in assimilate distribution. Re-sequencing of GNI-A1 in tetraploid wheat demonstrated the rich allelic repertoire of the wild emmer gene pool, including a rare allele which was present in two gene copies and contained a nonsynonymous mutation in the C-terminus of the protein. Using an F2 population generated from a cross between wild emmer accessions Zavitan, which carries the rare allele, and TTD140, we demonstrated that this unique polymorphism is associated with grain weight, independent of grain number. Moreover, we showed, for the first time, that GNI-A1 proteins are transcriptional activators and that selection targeted compromised activity of the protein. Our findings expand the knowledge of the genetic basis underlying trade-off between key yield components and may contribute to breeding efforts for enhanced grain yield.

Original languageEnglish
Pages (from-to)2353-2365
Number of pages13
JournalTheoretical And Applied Genetics
Volume132
Issue number8
DOIs
StatePublished - 1 Aug 2019
Externally publishedYes

Bibliographical note

Funding Information:
We highly appreciate the excellent technical support of the Peleg laboratory members. Specially, we thank N. Teboul for drawing in Fig.  4 . This research was supported by the Chief Scientist of the Israel Ministry of Agriculture and Rural Development (Grant #12-01-0005) and the US Agency for International Development Middle East Research and Cooperation (Grant # M34-037).

Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Genetics

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