A PARTHENOGENESIS allele from apomictic dandelion can induce egg cell division without fertilization in lettuce

Charles J Underwood1,2, Kitty Vijverberg3,4, Diana Rigola1, Shunsuke Okamoto1,5, Carla Oplaat3,6, Rik H M Op den Camp1, Tatyana Radoeva1, Stephen E Schauer7, Joke Fierens1, Kim Jansen1, Sandra Mansveld1, Marco Busscher3, Wei Xiong3, Erwin Datema1, Koen Nijbroek1, Evert-Jan Blom1, Ross Bicknell8, Andrew Catanach8, Sylvia Erasmuson8, Christopher Winefield9, Arjen J van Tunen1, Marcel Prins1, M Eric Schranz10, Peter J van Dijk11

  1. Keygene N.V., Wageningen, the Netherlands.
  2. Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
  3. Biosystematics Group, Wageningen University, Wageningen, the Netherlands.
  4. Naturalis Biodiversity Center, Radboud University, Nijmegen, the Netherlands.
  5. Takii & Co. Ltd, Plant Breeding and Experiment Station, Konan Shiga, Japan.
  6. National Reference Centre of Plant Health, National Plant Protection Organization, Wageningen, the Netherlands.
  7. Keygene Inc., Rockville, MD, USA.
  8. New Zealand Institute for Plant & Food Research, Lincoln, New Zealand.
  9. Lincoln University, Lincoln, New Zealand.
  10. Biosystematics Group, Wageningen University, Wageningen, the Netherlands. eric.schranz@wur.nl.
  11. Keygene N.V., Wageningen, the Netherlands. peter.van-dijk@keygene.com.

Abstract

Apomixis, the clonal formation of seeds, is a rare yet widely distributed trait in flowering plants. We have isolated the PARTHENOGENESIS (PAR) gene from apomictic dandelion that triggers embryo development in unfertilized egg cells. PAR encodes a K2-2 zinc finger, EAR-domain protein. Unlike the recessive sexual alleles, the dominant PAR allele is expressed in egg cells and has a miniature inverted-repeat transposable element (MITE) transposon insertion in the promoter. The MITE-containing promoter can invoke a homologous gene from sexual lettuce to complement dandelion LOSS OF PARTHENOGENESIS mutants. A similar MITE is also present in the promoter of the PAR gene in apomictic forms of hawkweed, suggesting a case of parallel evolution. Heterologous expression of dandelion PAR in lettuce egg cells induced haploid embryo-like structures in the absence of fertilization. Sexual PAR alleles are expressed in pollen, suggesting that the gene product releases a block on embryogenesis after fertilization in sexual species while in apomictic species PAR expression triggers embryogenesis in the absence of fertilization.

Presented By Kitty Vijverberg | ORCID iD

Cell & Developmental Bio, Genetics & Genome BiologyNicholas Liao2022-01 (Jan)