AtMYB103 regulates tapetum and trichome development in Arabidopsis thaliana

Abstract

SummaryThe AtMYB103 gene is a member of the R2R3 MYB gene family in Arabidopsis thaliana. Using the GUS reporter gene, AtMYB103 expression was found to be restricted to the tapetum of developing anthers. Employing RT-PCR and in situ hybridisation, we now show that AtMYB103 is also expressed in trichomes. GUS expression in trichomes was obtained by incorporating the coding and 3 H -untranslated regions of AtMYB103 into the promoter-GUS constructs. Sense and antisense technologies were used to downregulate AtMYB103 expression. In transgenic lines with reduced AtMYB103 transcript levels, pollen, tapetum and trichome development were altered. The majority of the pollen grains were distorted in shape and had reduced or no cytoplasmic content. Tapetal degeneration occurred early, and large opaque bodies appeared in the tapetal cytoplasm. In transgenic plants, trichomes on cauline and rosette leaves produced additional branches. These overbranched trichomes contained more nuclear DNA than the wild-type trichomes. The results indicate that AtMYB103 is required for tapetal development and microsporogenesis, and negatively regulates trichome endoreduplication linked to the trichome branching.

MYB transcription factor genes as regulators for plant responses: an overview

“…Similar observations were made in terms of organ-specific expression patterns: AtMYB7, AtMYB44 and AtMYB73 were expressed in all plant organs studied while AtMYB46 was only detected in siliques and AtMYB21 only in flower buds (Shin et al 2002). Several MYB-related genes expressed in anthers have been identified, namely AtMYB26 and AtMYB103 in Arabidopsis (Steiner-Lange et al 2003;Higginson et al 2003) and NtMYBAS1 in tobacco . In Arabidopsis, AtMYB103 gene expression was restricted to the tapetum of developing anthers and trichomes, down-regulation results in early tapetal degeneration and aberrant pollen.…”

PERSISTENT TAPETAL CELL1Encodes a PHD-Finger Protein That Is Required for Tapetal Cell Death and Pollen Development in Rice

“…We identified 1,569 down-regulated genes and 848 upregulated genes (2,417 in total) with a change in expression of 2-fold or more in the tapetum and/or microspores at stages 8 and 9 between the wild type and ptc1 (Supplemental Data Set S1). Some genes previously identified as critical for postmeiotic anther development were down-regulated in the ptc1 microarray data (Table I), including a Cys protease (OsCP1; Lee et al, 2004), a fatty acyl-CoA reductase homologous to Arabidopsis MS2 (Aarts et al, 1997), lipid transfer proteins (Osc4, OsC6, YY1, and Os09g0525500; Tsuchiya et al, 1992;Hihara et al, 1996), a stilbene synthase (YY2; Hihara et al, 1996), BURP domain-containing proteins (RA8 and OsRAFTIN; Jeon et al, 1999), a P450 family member (CYP704B2; , a ribosomeinactivating protein (RA39; Jeon et al, 1999), and the putative homolog of AtMYB103 (Higginson et al, 2003;Zhang et al, 2007). Consistent with the RT-qPCR analysis, PTC1 showed up-regulation in the ptc1 mutant (2.97-fold at stage 8, 5.49-fold at stage 9), whereas genes involved in early tapetal and pollen regulation, such as CYP703A3 (Aya et al, 2009), TDR (Li et al, 2006), UDT1 (Jung et al, 2005), and GAMYB (Kaneko et al, 2004;Liu et al, 2010; Table I), showed no significant change.…”

The Arabidopsis Transcription Factor MYB12 Is a Flavonol-Specific Regulator of Phenylpropanoid Biosynthesis

“…These include development (e.g. AtMYB0/GL1 [Oppenheimer et al, 1991;Esch et al, 1994;Shikazono et al, 1998], AtMYB66/WER [Lee and Schiefelbein, 1999], and AtMYB103 [Higginson et al, 2003]), signal transduction (e.g. AtMYB2 [Urao et al, 1993] and AtMYB34/ATR1 [Bender and Fink, 1998]), plant disease resistance (e.g.…”