Iron (Fe) is an essential micronutrient required for plant growth and development. However, its deficiency causes substantial yield losses, particularly in alkaline soils. Soybean (Glycine max) serves as an ideal model to study Fe deficiency chlorosis (IDC) due to its inefficient Fe uptake from the soil. Although the quantitative trait loci (QTL) associated with IDC tolerance were determined in soybean, the specific genes within these QTL regions remain unidentified. In this study, it was aimed to identify and analyze the expression levels of genes present in IDC-responsive soybean QTL under Fe deficiency. Through this investigation, 6593 genes were identified within 19 QTL linked to IDC tolerance in soybean, and among these, 607 genes exhibited differential expression under Fe deficiency conditions. Notably, the orthologs of 10 selected genes, referred to as the core group, were found to be induced in Fe-signaling mutants of Arabidopsis thaliana. These core group genes were enriched in metal transport and Fe-signaling pathways. Further examination of these genes in an IDC-sensitive soybean cultivar revealed their induction under Fe deficiency and high soil pH conditions. Particularly, GATA TRANSCRIPTION FACTOR12 (GATA12) stood out with significantly increased expression levels of approximately 5 and 20 times under Fe deficiency and high pH treatments, respectively. Coexpression network analyses of the core group genes highlighted the significance of the cluster containing GATA12 as a crucial integrator of Fe signaling between the epidermis-localized FER-LIKE IRON DEFICIENCY INDUCED TRANSCRIPTION FACTOR (FIT) and the stele-localized POPEYE (PYE) signaling networks. Overall, the findings suggest that GATA12 and its close paralogs may act in the transcriptional network linking the two Fe-signaling networks in the root stele and epidermis. This knowledge sheds light on the intricate mechanisms of Fe signaling in soybean and provides valuable insights for future studies on IDC tolerance and Fe-efficient cultivar development.
Arabidopsis, gene expression, iron deficiency, molecular networks, QTL, soybean
MAQBOOL, AMIR; ŞAHİN, Ahmet; BAKHSH, ALLAH; and AKSOY, EMRE
"Genome-wide identification of QTLs associated with iron deficiency tolerance in soybean reveals GATA12 as the integrator of iron signaling in roots,"
Turkish Journal of Botany: Vol. 47:
6, Article 4.
Available at: https://journals.tubitak.gov.tr/botany/vol47/iss6/4