A DELAY OF GERMINATION 1 (DOG1)‐like protein regulates spore germination in the moss Physcomitrium patens

Abstract

SUMMARYDELAY OF GERMINATION 1 is a key regulator of dormancy in flowering plants before seed germination. Bryophytes develop haploid spores with an analogous function to seeds. Here, we investigate whether DOG1 function during germination is conserved between bryophytes and flowering plants and analyse the underlying mechanism of DOG1 action in the moss Physcomitrium patens. Phylogenetic and in silico expression analyses were performed to identify and characterise DOG1 domain‐containing genes in P. patens. Germination assays were performed to characterise a Ppdog1‐like1 mutant, and replacement with AtDOG1 was carried out. Yeast two‐hybrid assays were used to test the interaction of the PpDOG1‐like protein with DELLA proteins from P. patens and A. thaliana. P. patens possesses nine DOG1 domain‐containing genes. The DOG1‐like protein PpDOG1‐L1 (Pp3c3_9650) interacts with PpDELLAa and PpDELLAb and the A. thaliana DELLA protein AtRGA in yeast. Protein truncations revealed the DOG1 domain as necessary and sufficient for interaction with PpDELLA proteins. Spores of Ppdog1‐l1 mutant germinate faster than wild type, but replacement with AtDOG1 reverses this effect. Our data demonstrate a role for the PpDOG1‐LIKE1 protein in moss spore germination, possibly alongside PpDELLAs. This suggests a conserved DOG1 domain function in germination, albeit with differential adaptation of regulatory networks in seed and spore germination.

Proteome plasticity during Physcomitrium patens spore germination – from the desiccated phase to heterotrophic growth and reconstitution of photoautotrophy

“…A homolog of HY3 that we detected in dry spores (Data S3) was rapidly degraded within 48 h. Based on this finding, it could play an analogous role, especially since it was shown that P. patens spore germination is inhibited by far-red light as well (Vesty et al, 2016). Recently, it was found that a ortholog of the Arabidopsis DELAY OF GERMINATION 1 (Bentsink et al, 2006) alongside DELLA proteins regulates spore germination in P. patens highlighting another protein network important for both spore and seed germination (Vollmeister et al, 2023).…”