The maizefused leaves1(fdl1) gene controls organ separation in the embryo and seedling shoot and promotes coleoptile opening

Abstract

HighlightThis study provides the first characterization of an R2R3 family MYB transcription factor involved in cuticle and epicuticular wax deposition, whose action is confined to maize embryogenesis and juvenile phase.

The FUSED LEAVES1/ADHERENT1Regulatory Module Is Required For Maize Cuticle Development And Organ Separation

“…Homozygous fdl1-Mu mutant plants showed organ fusion defects at the seedling stage (Supplemental Figure 5). Similar to ad1 mutants, a reduced amount of epicuticular wax crystals, increased loss of epidermal water and faster chlorophyll leaching were also observed in fdl1-Mu plants (Supplemental Figure 5) mirroring what was previously reported for another fdl1 allele (La Rocca et al, 2015). Using RNA in situ hybridizations, we determined that FDL1 showed strong expression in the epidermal layer of young leaves and tassels, in a pattern remarkably similar to AD1 ( Figure 5B, Supplemental Figure 5).…”

“…wax1, wax2, lcr, hth and lacs1 lacs2) indicating that cuticle formation involves a complex array of components, each critical for plant development (Jenks et al, 1996;Wellesen et al, 2001;Chen et al, 2003;Kurdyukov et al, 2006b;Kurdyukov et al, 2006a;Bird et al, 2007;Panikashvili et al, 2007;Weng et al, 2010). While the mechanism of how wax and cutin biosynthetic pathway mutants affect cuticle structure, composition and properties is not well understood, it is clear that proper cuticle formation which starts from L1 cells during embryo development, plays an essential role in maintaining organ separation and preventing postgenital fusions (Yephremov et al, 1999;Pruitt et al, 2000;Ingram and Nawrath, 2017) Genome-wide DAP-seq analysis indicated that FDL1, a previously described MYB TF (La Rocca et al, 2015), directly binds to many genes involved in wax biosynthesis, including those encoding enzymes, transporters and upstream transcriptional regulators. A major category of targets bound by FDL1 and validated by qRT-PCR belongs to the KCS gene family, including AD1 itself.…”

“…Recently, in maize, two MYB family TFs, FUSED LEAVES1/MYB94 (FDL1) and GLOSSY3/MYB97, were identified as positive regulators of leaf cuticular wax accumulation. While glossy3 mutants did not show any fusion defects, fdl1 mutants showed organ fusion during the juvenile phase (Liu et al, 2012;La Rocca et al, 2015).…”

“…The previously characterized maize mutant fused leaves1 (fdl1) has a phenotype similar to ad1, in particular regarding seedling leaf blade fusion and cuticular wax accumulation defects. FDL1 (GRMZM2G056407/Zm00001d022227) encodes MYB94, a MYB transcription factor (La Rocca et al, 2015) whose Arabidopsis homologs are known to be involved in the regulation of cuticular wax biosynthesis Seo et al, 2011;La Rocca et al, 2015). To understand whether AD1 was regulated by FDL1/MYB94, we obtained a transposon insertion (mu1092890) in the FDL1 gene, which disrupts its second exon ( Figure 5A).…”

Overexpression of the TaSHN1 transcription factor in bread wheat leads to leaf surface modifications, improved drought tolerance, and no yield penalty under controlled growth conditions

“…In concert with stomata, the cuticle acts as an interface between plants and their surrounding environment, protecting them against a variety of biotic and abiotic stresses (Chen et al, ; Reina‐Pinto & Yephremov, ; Yeats & Rose, ). The cuticle also plays an essential role in plant development during pollen maturation (Shi, Cui, Yang, Kim, & Zhang, ; Zhang, Yang, & Shi, ) and in preventing organ fusion during seedling development (Kurdyukov et al, ; La Rocca et al, ; Luo, Xue, Hu, Wang, & Chen, ). However, the most important function of the cuticle is to protect aerial plant tissues and organs against water loss (Aharoni et al, ; Borisjuk, Hrmova, & Lopato, ; Yeats & Rose, ).…”