Arabidopsis seed germination speed is controlled by SNL histone deacetylase-binding factor-mediated regulation of AUX1

Abstract

Histone acetylation is known to affect the speed of seed germination, but the molecular regulatory basis of this remains ambiguous. Here we report that loss of function of two histone deacetylase-binding factors, SWI-INDEPENDENT3 (SIN3)-LIKE1 (SNL1) and SNL2, results in accelerated radicle protrusion and growth during seed germination. AUXIN RESISTANT 1 (AUX1) is identified as a key factor in this process, enhancing germination speed downstream of SNL1 and SNL2. AUX1 expression and histone H3 acetylation at lysines 9 and 18 is regulated by SNL1 and SNL2. The D-type cyclins encoding genes CYCD1;1 and CYCD4;1 display increased expression in AUX1 over-expression lines and the snl1snl2 double mutant. Accordingly, knockout of CYCD4;1 reduces seed germination speed of AUX1 over-expression lines and snl1snl2 suggesting the importance of cell cycling for radicle protrusion during seed germination. Together, our work identifies AUX1 as a link between histone acetylation mediated by SNL1 and SNL2, and radicle growth promoted by CYCD1;1 and CYCD4;1 during seed germination.

Interplay between REVEILLE1 and RGA‐LIKE2 regulates seed dormancy and germination in Arabidopsis

“…Consistent with the RNA-seq analysis, the expression levels of four genes involved in seed germination or dormancy, GA3ox2, AUX1, TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE1 (TTL1) and OPEN STOMATA1 (OST1) (Rosado et al, 2006;Nakashima et al, 2009;Wang et al, 2016), were markedly higher or lower in rve1 and rgl2 seeds relative to WT seeds (Fig. Consistent with the RNA-seq analysis, the expression levels of four genes involved in seed germination or dormancy, GA3ox2, AUX1, TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE1 (TTL1) and OPEN STOMATA1 (OST1) (Rosado et al, 2006;Nakashima et al, 2009;Wang et al, 2016), were markedly higher or lower in rve1 and rgl2 seeds relative to WT seeds (Fig.…”

Combined transcriptome and translatome analyses reveal a role for tryptophan‐dependent auxin biosynthesis in the control of DOG1‐dependent seed dormancy

“…The concentrations of Trp and derived IPyA, which are the main Trp‐dependent auxin synthesis precursors (Ljung, ), were increased in the after‐ripened seeds. Interestingly, the auxin influx carrier AUX1 was recently reported to have a positive role in seed germination regulated by histone H3K9K18 deacetylation (Wang et al ., ). Moreover, the cell cycling‐related Cyclin D‐type ( CYCD ) genes that are downstream of AUX1 and are important for radicle promotion (Wang et al ., ) were also among the dormancy and cordycepin‐inhibited genes in our analyses (Table S5).…”

“…Interestingly, the auxin influx carrier AUX1 was recently reported to have a positive role in seed germination regulated by histone H3K9K18 deacetylation (Wang et al ., ). Moreover, the cell cycling‐related Cyclin D‐type ( CYCD ) genes that are downstream of AUX1 and are important for radicle promotion (Wang et al ., ) were also among the dormancy and cordycepin‐inhibited genes in our analyses (Table S5). This might be a downstream effect of the auxin pathway as auxin is known to influence the cell division in both embryonic and vegetative stages (De Veylder et al ., ).…”

Developmental transitions: integrating environmental cues with hormonal signaling in the chromatin landscape in plants

“…In addition, SNL co-repressors slow the speed of seed germination by inhibiting auxin synthesis and directly repress the expression of auxin transporters such as AUXIN RESISTANT1 (AUX1) [82]. Increased H3 lysine 9 or 18 acetylation (H3K9/18 ac) at AUX1 was observed in snl1 snl2 mutants.…”