Comparative analysis of iron deficiency chlorosis responses in soybean (Glycine max) and barrel medic (Medicago truncatula)

Legume grains have an important socio-economical role, being highly utilized in human and animal nutrition. Although iron (Fe) is abundant in the earth’s crust, its limited solubility makes it poorly bioavailable for plants, contributing to iron deficiency chlorosis (IDC). In this work the physiological and molecular mechanisms associated with IDC were studied, namely, the mechanisms involved on Fe deficiency response, as well as a new Fe metabolism related gene in two important legume crops, Glycine max and Medicago truncatula. Fe deficient plants developed: decreased root and shoot length, increased number of secondary roots and lower chlorophyll levels. Fe shoot content decreased six- and 11-fold for G. max and M truncatula in Fe-deficiency. Whilst in G. max roots no significant differences were detected, in M. truncatula roots Fe decreased nine-fold in Fe-deficiency. Genes involved in Fe uptake (FRO2-like and IRT1-li ke), were over-expressed in roots of Fe-sufficient G. max and in Fe-deficient M. truncatula. VIT1-like, YSL1-likea nd ferritin presented higher expression levels in Fe-sufficient shoots and roots, whereas NRAMP3-like and GCN2-like showed higher expression values in Fe-deficiency.