Bentsink, L. | bioRxiv Science

bioRxiv2021

DELAY OF GERMINATION 6, encoding the ANAC060 transcription factor, inhibits seed dormancy

The timing of seed germination is regulated by seed dormancy. There is ample natural variation for seed dormancy among as well as within plant species. In Arabidopsis several DELAY OF GERMINATION quantitative trait loci have been identified, of which DOG1 is best studied. Here we report the identification of DOG6, a quantitative trait locus with a similar strong effect on seed dormancy as DOG1. DOG6 affects the timing of germination both in laboratory as well as in field conditions. Complementation cloning revealed that DOG6 encodes the membrane bound transcription factor ANAC060. The absence of the ANAC060 protein or its sequestration outside the nucleus results in increased seed dormancy levels. The different natural variants of ANAC060 differ for the presence of the membrane binding domain, either due to the fact that this domain is absent in the genomic sequence or because the cDNA is alternatively spliced. Our data indicates that ANAC060 regulates seed dormancy by among others binding to and regulating the expression of protein phosphatases 2C class A proteins including PROTEIN PHOSPHATASE 2CA (PP2CA), ABI FIVE BINDING PROTEIN 3 (AFP3) and HIGHLY ABA-INDUCED PP2C GENE 3 (HAI3). Significance StatementANAC transcription factors are known to effect plant development as well as the response of plants to their environment. Here, we present the identification of DELAY OF GERMINATION 6 (DOG6), a seed dormancy quantitative trait locus that encodes the ANAC060 transcription factor. We have identified different natural alleles of ANAC060 and show that these genetic variants determine the localization of the protein. ANAC060 alleles that lack the membrane binding domain end up in the nucleus. Hence they affect transcription and as such attenuate seed dormancy.

plant biology↗

bioRxiv2019

Transcriptome and translatome profiling and translational network analysis during seed maturation reveals conserved transcriptional and distinct translational regulatory patterns

Seed maturation is an important plant developmental process that follows embryo development. It is associated with a series of physiological changes such as the establishment of desiccation tolerance, seed longevity and seed dormancy. However, the translational dynamics associated with seed maturation, especially its connection with seed germination remains largely elusive. Here transcriptome and translatome profiling were performed during seed maturation. During seed maturation we observed a gradual disappearance of polysomes and a relative increase of monosomes, indicating a gradual reduction of global translation. Comparing the levels of polysomal associated mRNAs with total mRNA levels showed that thousands of genes are translationally regulated at early sates of maturation, as judged by dramatic changes in polysomal occupancy. By including previous published data from germination and seedling establishment, a translational regulatory network: SeedTransNet was constructed. Network analysis identified hundreds of gene modules with distinct functions and transcript sequence features indicating the existence of separate translational regulatory circuits possibly acting through specific regulatory elements. The regulatory potential of one such element was confirmed in vivo. The network identified several seed maturation associated genes as central nodes, and we could confirm the importance of many of these hub genes with a maturation associated seed phenotype by mutant analysis. One of the identified regulators an AWPM19 family protein PM19-Like1 (PM19L1) was shown to regulate seed dormancy and longevity. This putative RBP also affects the transitional regulation of one its, by the SeedTransNet identified, target mRNAs. Our data shows the usefulness of SeedTransNet in identifying regulatory pathways during seed phase transitions.

systems biology↗