MYB10 and MYB72 Are Required for Growth under Iron-Limiting Conditions

Abstract

Iron is essential for photosynthesis and is often a limiting nutrient for plant productivity. Plants respond to conditions of iron deficiency by increasing transcript abundance of key genes involved in iron homeostasis, but only a few regulators of these genes have been identified. Using genome-wide expression analysis, we searched for transcription factors that are induced within 24 hours after transferring plants to iron-deficient growth conditions. Out of nearly 100 transcription factors shown to be up-regulated, we identified MYB10 and MYB72 as the most highly induced transcription factors. Here, we show that MYB10 and MYB72 are functionally redundant and are required for plant survival in alkaline soil where iron availability is greatly restricted. myb10myb72 double mutants fail to induce transcript accumulation of the nicotianamine synthase gene NAS4. Both myb10myb72 mutants and nas4-1 mutants have reduced iron concentrations, chlorophyll levels, and shoot mass under iron-limiting conditions, indicating that these genes are essential for proper plant growth. The double myb10myb72 mutant also showed nickel and zinc sensitivity, similar to the nas4 mutant. Ectopic expression of NAS4 rescues myb10myb72 plants, suggesting that loss of NAS4 is the primary defect in these plants and emphasizes the importance of nicotianamine, an iron chelator, in iron homeostasis. Overall, our results provide evidence that MYB10 and MYB72 act early in the iron-deficiency regulatory cascade to drive gene expression of NAS4 and are essential for plant survival under iron deficiency.

Two bHLH Transcription Factors, bHLH34 and bHLH104, Regulate Iron Homeostasis in Arabidopsis thaliana

“…Two MYB transcription factors, MYB10 and MYB72, were identified as Fe deficiency-responsive genes, which are responsible for the activation of expression of the NAS4 gene in Fe-deficient conditions in Arabidopsis (Palmer et al, 2013). Considering the fact that the bhlh34bhlh104 mutants display interveinal chlorosis similar to nas4x-1 mutants (Klatte et al, 2009), we asked whether these two MYB genes are affected in the bhlh34bhlh104 mutants.…”

Iron-Nicotianamine Transporters Are Required for Proper Long Distance Iron Signaling

“…Notably, even though the proportion of genes with appropriate expression is higher in leaves, a large fraction (32.8%) of the iron-regulated genes in leaves of DM plants had Table I. Comparison of the expression of select iron deficiency-regulated genes (Petit et al, 2001;Stacey et al, 2002Stacey et al, , 2008Mukherjee et al, 2006;Schaaf et al, 2006;Wang et al, 2007;Klatte et al, 2009;Haydon et al, 2012;Palmer et al, 2013;Fourcroy et al, 2016;Mai et al, 2016;Sisó -Terraza et al, 2016;Yan et al, 2016;Ziegler et al, 2017) (Petit et al, 2001;Stacey et al, 2002Stacey et al, , 2008Mukherjee et al, 2006;Cohu and Pilon, 2007;Wang et al, 2007;Klatte et al, 2009) in ysl1ysl3 DM and wild-type shoots *, P , 0.05; **, P , 0.001; N.S. indicates that the difference was not significant (P .…”

Cloning and bioinformatic analysis of transcription factor MYB10 from the red-leaf peach

“…In recent years, most research concerning anthocyanin metabolism has focused on the regulation of transcription factors, especially the interaction between MYB, bHLH, and WD40 proteins (Medina-Puche et al, 2014). These transcription factors regulate biosynthesis of anthocyanin, as shown in Arabidopsis thaliana (Palmer et al, 2013), petunias (Boase et al, 2015), and a number of other plants (Dong et al, 2015;Wan et al, 2015). Although the MYB family member MYB10 (GenBank accession No.…”