ZmMYB14 is an important transcription factor involved in the regulation of the activity of the ZmBT1 promoter in starch biosynthesis in maize

Abstract

The biosynthesis of starch is a complex process that depends on the regulatory mechanisms of different functional enzymes, and transcriptional regulation plays an important role in this process. Brittle 1, encoded by BT1, is a transporter of adenosine diphosphate-glucose, which plays an important role in the biosynthesis of starch in the endosperm of cereals. Here, we report that the promoter (pZmBT1) of the maize BT1 homolog, ZmBT1, contains an MBSI site (TAACTG), which is important for its activity. Moreover, high expression level of the gene for ZmMYB14 transcription factor was observed in the maize endosperm; its expression pattern was similar to those of the starch synthesis-related genes in maize seeds. ZmMYB14 is a typical 2R-MYB transcription factor localized in the nucleus and possessed transcriptional activation activity. ZmMYB14 could bind to the region of pZmBT1 from -280 to -151 bp and promote its activity through the TAACTG site. It was also observed to promote the activity of pZmSh2, pZmBt2, pZmGBSSI, pZmSSI, and pZmSBE1 in the maize endosperm in transient gene overexpression assays. Furthermore, ZmMYB14 was also shown to bind directly to the promoters of six starch-synthesizing genes, ZmGBSSI, ZmSSI, ZmSSIIa, ZmSBE1, ZmISA1, and ZmISA2 in yeast. These findings indicate that ZmMYB14 functions as a key regulator of ZmBT1 and is closely related to the biosynthesis of starch. Our results provide crucial information related to the regulation of starch biosynthesis in maize and would be helpful in devising strategies for modulating starch production in maize endosperm.

High Temporal-Resolution Transcriptome Landscape of Early Maize Seed Development

“…The starch and protein accumulation were decreased in o11, a classic seed mutant with a small and opaque endosperm (Nelson, 1981). The MYB155 is reported to be highly expressed in the maize endosperm and involved in the process of starch biosynthesis (Xiao et al, 2017). Collectively, these identified seedspecific genes and TFs in group IV-B might be critical for the grainfilling process, according to the function of the known genes and TFs in this group.…”

Multifunctional Roles of Plant Cuticle During Plant-Pathogen Interactions

“…Reductions in the levels of certain cutin monomers and/or wax components that help to repress the expression and function of pathogenic effectors involved in virulence and pathogenicity, such as Arabidopsis CYP86A2 . This gene is involved in the formation of C16 and C18 hydroxy FAs, which have direct inhibitory impacts against certain pathogens, such as P. syringae ( Xiao et al, 2017 ).…”

Molecular identification of the key starch branching enzyme-encoding gene SBE2.3 and its interacting transcription factors in banana fruits

“…7c). MYBs compose a large family of transcriptional regulators that have been shown to be involved in starch biosynthesis in hull-less barley 48 and maize 49 . In hullless barley, the coexpression of MYB and SBE2b was found to significantly contribute to starch biosynthesis during grain development 48 .…”