Comparative analysis of embryo proper and suspensor transcriptomes in plant embryos with different morphologies

Significance How plant embryos are differentiated into embryo proper and suspensor regions following fertilization is a major unanswered question. The suspensor is unique because it can vary in morphology in different plant species. We hypothesized that regulatory genes controlling the specification of embryo proper and suspensor regions should be shared by all plants irrespective of embryo morphology. We compared embryo proper and suspensor transcriptomes of plants with distinct suspensor morphologies. Scarlet runner bean and common bean have highly specialized giant suspensor regions; soybean and Arabidopsis suspensors are smaller and less specialized. We uncovered a small set of embryo proper– and suspensor-specific transcription factors shared by all embryos irrespective of morphology, suggesting that they play an important role in early embryo differentiation.