The MYB107 Transcription Factor Positively Regulates Suberin Biosynthesis

Abstract

Suberin, a lipophilic polymer deposited in the outer integument of the Arabidopsis (Arabidopsis thaliana) seed coat, represents an essential sealing component controlling water and solute movement and protecting seed from pathogenic infection. Although many genes responsible for suberin synthesis are identified, the regulatory components controlling its biosynthesis have not been definitively determined. Here, we show that the Arabidopsis MYB107 transcription factor acts as a positive regulator controlling suberin biosynthetic gene expression in the seed coat. MYB107 coexpresses with suberin biosynthetic genes in a temporal manner during seed development. Disrupting MYB107 particularly suppresses the expression of genes involved in suberin but not cutin biosynthesis, lowers seed coat suberin accumulation, alters suberin lamellar structure, and consequently renders higher seed coat permeability and susceptibility to abiotic stresses. Furthermore, MYB107 directly binds to the promoters of suberin biosynthetic genes, verifying its primary role in regulating their expression. Identifying MYB107 as a positive regulator for seed coat suberin synthesis offers a basis for discovering the potential transcriptional network behind one of the most abundant lipid-based polymers in nature.

PRX2 and PRX25, peroxidases regulated by COG1, are involved in seed longevity in Arabidopsis

“…The prx2 prx25 and prx2 prx25 prx71 mutant lines presented a structure comparable to the WT. Tannins are deposited in the endothelium, which is observed as a broad brown pigment layer (Gou et al, ). This layer was also very similar between the WT and mutants.…”

“…This apoplastic lipid barrier is located on the PL cell walls of the outer integument of the seed coat (Molina et al, ). It has been postulated to have a function in dormancy (Fedi et al, ) and in abiotic stress protection during germination (Gou et al, ). Our work demonstrates that suberin deposition in the PL layer of testa also increases seed tolerance to deterioration and it constitutes the first barrier protecting the embryo from this stress.…”

“…Seed coat lipid polyester analysis of the gpat5 mutant revealed a strong reduction in 22:0/24:0 fatty acids and their derivatives, in agreement with a reduction in seed coat suberin content observed after Sudan Red staining (Beisson, Li, Bonaventure, Pollard, & Ohlrogge, ). Several of these suberin biosynthesis genes are positively regulated in seeds by MYB107, a transcription factor (TF) that directly binds directly to their promoters (Gou et al, ). On the other hand, suberin transport to the cell wall may occur through the secretory pathway and, in part, also mediated by ATP‐binding cassette (ABC) transporters and/or lipid transfer proteins.…”

Disruption of glycosylphosphatidylinositol‐anchored lipid transfer protein 15 affects seed coat permeability in Arabidopsis

“…The large reductions of ω‐hydroxy fatty acids and α,ω‐dicarboxylic acids with 22 and 24 carbon atoms in fatB and gpat5 caused remarkable increases in seed coat permeability to tetrazolium salt (Beisson et al ., ). The increased seed coat permeability was also detected in several mutants, which were defective in suberin biosynthesis ( far1 far4 far5 and rwp1 ) and export ( ltpg4 ltpg6 , awake1 , and abcg2 abcg6 abcg20 ), and transcriptional activators that regulate suberin biosynthesis ( myb9 and myb107 ) (Gou et al ., , ; Vishwanath et al ., ; Edstam and Edqvist, ; Yadav et al ., ; Lashbrooke et al ., ; Fedi et al ., ). Consistent with previous reports, increased seed coat permeability of ltpg15 was observed in tetrazolium penetration assay (Figure ).…”

A comparative transcriptomic approach to understanding the formation of cork

“…Although a set of transcription factors belonging to MYB and NAC families has very recently been related to suberin accumulation (Kosma et al 2014;Gou et al 2017;Lashbrooke et al 2016;Legay et al 2016;Verdaguer et al 2016), only MYB102 and MYB107 were highlighted as upregulated in cork oak tissue according to DEGseq. Nevertheless, we identified several genes that may be involved in regulating phellogen activity.…”