Over‐expression of the Arabidopsis AtMYB41 gene alters cell expansion and leaf surface permeability

Abstract

SummaryThe Arabidopsis AtMYB41 gene encodes an R2R3-MYB transcription factor whose expression is not detectable under normal growth conditions in any organ or at any developmental stage analysed. It is expressed at high levels in response to drought, ABA and salt treatments, suggesting a possible role in stress responses. Transgenic lines over-expressing this transcription factor showed a pleiotropic phenotype similar to that exhibited by some mutants that affect cuticle biosynthesis. This includes a dwarf appearance, dependent on smaller cells with abnormal morphology, enhanced sensitivity to desiccation, and enhanced permeability of leaf surfaces, suggesting discontinuity in the cuticle. The expression of genes involved in lipid metabolism and transport, in cell-wall modifications and cell expansion, genes coding for membrane-associated proteins and genes specifically involved in cuticle metabolism was differentially modulated between wild-type and transgenic plants, suggesting a direct or indirect role of AtMYB41 in the regulation of their transcription. Taken together, our results suggest that AtMYB41 is part of a complex network of transcription factors controlling cell expansion and cuticle deposition in response to abiotic stress.

Stress‐induced changes in the Arabidopsis thaliana transcriptome analyzed using whole‐genome tiling arrays

“…Many stress-responsive genes known from the literature, such as several DREB type ERF/AP2 like transcription factor genes, NCED3, ATHB-7, RD29b, a PP2C and diverse LEA genes, were strongly induced, preferentially in response to salt and osmotic stress, ABA treatment and after prolonged exposure to high temperatures (Figure 1a-c) (YamaguchiShinozaki and Shinozaki, 1994;Soderman et al, 1996;Sakuma et al, 2002;Xiong et al, 2002;Schweighofer et al, 2004;Barrero et al, 2006;Kilian et al, 2007;Cominelli et al, 2008;Hundertmark and Hincha, 2008). Seedlings transferred to cold exhibited a strong and transient induction of cold-inducible CBF transcription factor genes ( Figure 1d) (Thomashow, 1999;Chinnusamy et al, 2007).…”

Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid

“…In addition, the presence of cis-ABA-responsive elements in the promoters of some wax-related genes, such as CER6 (Hooker et al, 2002), suggests that ABA directly regulates wax synthesis. Moreover, some Arabidopsis transcriptions factors that are associated with cuticle biosynthesis, such as MYB96, are known to be regulated by ABA and to be part of the ABA-mediated signaling pathway (Cominelli et al, 2008;Seo et al, 2009;Lee et al, 2015). Lastly, Cui et al (2016) showed that the expression of some cuticle related genes was affected in Arabidopsis ABA mutants, further suggesting a role for ABA in cuticle development.…”

“…However, the expression of other regulatory factors, such as CER7, CD2, and SHINE1, was unaffected, suggesting that ABA regulates cuticle formation by influencing the expression of a subset of the transcription factors associated with cuticle formation, but not the entire regulatory network. In Arabidopsis, AtMYB41, AtMYB30, AtMYB16, AtMYB106, and AtMYB96 have been shown to regulate cuticular wax formation and, with the exception of AtMYB96, to also regulate cutin synthesis (Cominelli et al, 2008;Raffaele et al, 2008;Seo et al, 2011;Oshima et al, 2013). Since the tomato gene Solyc03g116100 was identified as the closest homolog of both AtMYB30 and AtMYB96, it may regulate both leaf cutin and wax formation; however, this remains to be tested.…”

The Formation and Function of Plant Cuticles

“…While MYB96 positively regulates wax production in response to stress, MYB41 mediates the negative regulation of cutin biosynthesis in response to similar stresses. MYB41 is induced by ABA, drought, and osmotic stress, leading to the down-regulation of cutin biosynthesis genes and the disruption of cuticle structure (Cominelli et al, 2008).…”