Redundant PLETHORA activity promotes development of early embryonic cell lineages in Arabidopsis

Abstract

The BABY BOOM/PLETHORA4 (BBM/PLT4) transcription factor has received much attention due to its ability to induce somatic and zygotic embryogenesis, two processes of pivotal importance in plant breeding. Loss of additional AINTEGUMENTA-LIKE/PLETHORA (AIL/PLT) genes, encoding members of the APETALA2 transcription factor family, causes embryo arrest and abortion, but whether BBM/PLT4 provides specific information for embryo development has remained unknown. Here, we reveal that AIL/PLT members are expressed in partially overlapping domains from their first appearance in the apical cell daughter of the zygote. Redundant early embryonic activity of BABY BOOM/PLT4 and PLT2 triggers development of the apical cell lineage and is required to initiate embryonic primordia. Furthermore, promoter swap experiments show that PLT1 and PLT3 expression in the expression domains of PLT2 and BABY BOOM/PLT4 is sufficient to rescue plt2 bbm double mutants. Our data indicate that generic AIL/PLT factors, involved in maintenance of stem cells, promotion of cell division and suppression of cell differentiation, provide the necessary information to initiate embryogenesis in Arabidopsis.

Application of Developmental Regulators for Enhancing Plant Regeneration and Genetic Transformation

“…PLETHORA (PLT) transcription factors, members of the APETALA2/ETHYLENE-RESPONSIVE ELEMENT BINDING PROTEIN family, play crucial roles in post-embryonic development [178,179]. Merijn et al conducted a series of experiments to prove that the ectopic overexpression of PLT promoted somatic embryogenesis [180]. In this investigation, it is substantiated that the collaborative action of PLT2 and BBM redundantly facilitates the progression of the zygote into a developing embryo.…”

Multifaceted roles of transcription factors during plant embryogenesis

“…Arroyo -Herrera et al, 2008;Bouchabke-Coussa et al, 2013;Mookkan et al, 2017;Kadri et al, 2021, embryogenesis (Horstman et al, 2017b;Kerstens et al, 2022). In addition, BBM and PLT2-induced somatic embryogenesis is dosage-dependent with higher levels of BBM/PLT2 resulting in the initiation of embryogenesis (Horstman et al, 2017b).…”

“…Elevated expression of BBM-like PLT gene members, such as PLT1, PLT2, PLT3 , and PLT7 , has been demonstrated to induce somatic embryogenesis. Notably, PLT1 and PLT3 were found to recover early-stage embryo defects of plt2 bbm mutants, suggesting a redundant and overlapping role of BBM and BBM-like genes in embryogenesis ( Horstman et al., 2017b ; Kerstens et al., 2022 ). In addition, BBM and PLT2-induced somatic embryogenesis is dosage-dependent with higher levels of BBM/PLT2 resulting in the initiation of embryogenesis ( Horstman et al., 2017b ).…”

“… A representative model of transcription factor networks during plant embryogenesis. This model summarizes our recent research and the latest developments in the field regarding transcription factor networks in embryogenesis in Arabidopsis and other crop species ( Horstman et al., 2017a ; Pelletier et al., 2017 ; Ueda et al., 2017 ; Chen et al., 2018 ; Kong et al., 2020 ; Tian et al., 2020 ; Wang et al., 2020 ; Chen et al., 2022a ; Kerstens et al., 2022 ; Paul et al., 2022 ; Khanday et al., 2023 ; Purwestri et al., 2023 ; Zhao et al., 2023 ). Transcription factors in purple usually promote embryogenesis, while TFs in gray suppress the process.…”