Arabidopsis MDN1 Is Involved in the Establishment of a Normal Seed Proteome and Seed Germination

Abstract

Seed germination and formation are the beginning and ending, respectively, of a plant life cycle. These two processes are under fine regulation by the internal genetic information. Previously, we demonstrated that Arabidopsis MIDASIN 1 (MDN1) is required for ribosome biogenesis, and its dysfunction leads to pleiotropic developmental phenotypes, including impaired embryogenesis and slow seed germination. In this study, we further found that the weak mutant of MDN1, mdn1-1, exhibits an increased seed size phenotype. Seed proteomic analysis reveals that a number of proteins involved in seed development and response to external environments are mis-regulated by the MDN1 dysfunction. Many 2S seed storage proteins (SSPs) and late embryogenesis abundant (LEA) proteins are over-accumulated in the dry seeds of mdn1-1. Further, some genes encoding seed storage reserves are also upregulated in mdn1-1 seedlings. More interestingly, abscisic acid-insensitive 5 (ABI5) is over-accumulated in mdn1-1 seeds, and the loss of its function partially rescues the low seed germination rate of mdn1-1. Together, this study further demonstrates that MDN1 is essential for establishing a normal seed proteome, and its mutation triggers ABI5-mediated repression of seed germination.

AFP2 inhibits ABA responses during germination without ABI5 degradation but DWAs reduce desiccation tolerance

“…Within the numerous available seed proteomic reports (Narula et al, 2016), studies directly aiming at the identification of protein involved in seed longevity/viability present in dry seeds unveiled 309 differentially accumulated proteins in GERMINATION ABILITY AFTER STORAGE (GAAS) lines (Nguyen et al, 2015), 320 in mdn1-1 (Li et al, 2019), and 442 in vps29 mutants (Durand et al, 2019). The study using GAAS lines exploited natural variation in seed storability and proposed that the highly abundant Cruciferin storage proteins (CRA, CRB and CRC) act as a ROS buffering system (Nguyen et al, 2015).…”

“…Proteins over-accumulated exclusively in the unusual combination of extreme ABA resistance and seed storability (Cluster IV) include a GIBBERELLIN METHYLTRANSFERASE, which is normally expressed during seed maturation, leading to inactivation of GA (Varbanova et al, 2007), MIDASIN1 (MDN1) previously shown to be required for a proper shaping of the seed maturation proteome (Li et al, 2019), and a Pumilio RNA binding protein (APUM24), for which loss of function leads to aborted seeds (Maekawa et al, 2017). These seeds also over-accumulate a beta-glucoside that releases ABA from a conjugated form (AtBG1) (Lee et al, 2006) and is up-regulated by ABA-deficiency (Chauffour et al, 2019).…”

Exogenous Gibberellin Promotes the Germination of Phellodendron Chinense Schneid Seeds by Regulating the Expression of Phytohormone Related Genes and Anabolic Proteins

“…These proteins regulate catabolism [44], energy metabolism [45], anabolism, and defense reactions [46]. A previous study showed that rate of seed germination in Arabidopsis midasin1-1 (mdn1-1) was decreased by increasing the expression levels of SEED STORAGE ALBUMIN (SESA)1/3/4/5, EMBRYO SAC DEVELOPMENT ARREST4, and ABI5 compared with wild type (Col-0) [47]. In the present study, 17 proteins were identi ed in the Phellodendron chinense Schneid seeds during germination under normal conditions.…”

Mutation of an Essential 60S Ribosome Assembly Factor MIDASIN 1 Induces Early Flowering in Arabidopsis

“…The flc-3 (104 bp deletion in the first exon), flk-4 (Salk_112850), fve-4 (TGG to TGA mutation in the 6th exon), co (SAIL_24_H04), ft-10 (GABI_290E08), and clf-28 (SALK_139371) mutants were kindly provided by prof. Scott Michaels (Indiana University Bloomington). The double mutant of mdn1-1 abi5 had been described in our previous study [ 51 ]. Seedlings and plants were grown under 16 h light/8 h dark (LD, long day) or 8 h light/16 h dark (SD, short day) conditions at 21 °C.…”