IRONing out stress problems in crops: a homeostatic perspective

Abstract

Iron (Fe) is essential for plant growth and therefore plays a key role in influencing crop productivity worldwide. Apart from its central role in chlorophyll biosynthesis and oxidative phosphorylation (electron transfer), it is an important constituent of many enzymes involved in primary metabolism. Fe has different accessibilities to the roots in the rhizosphere depending upon whether it is ferrous (soluble) or ferric (insoluble) oxidation stages, which in turn, determine two kinds of Fe uptake strategies employed by the plants. The reduction strategy is exclusively found in non‐graminaceous plants wherein the ferrous Fe2+ is absorbed and translocated from the soil through specialized transporters. In contrast, the chelation strategy (widespread in graminaceous plants) relies on the formation of Fe (III)‐chelate complex as the necessary requirement of Fe uptake. Once inside the cell, Fe is translocated, compartmentalized and stored through a common set of physiological processes involving many transporters and enzymes whose functions are controlled by underlying genetic components, so that a fine balance of Fe homeostasis is maintained. Recently, molecular and mechanistic aspects of the process involving the role of transcription factors, signaling components, and cis‐acting elements have been obtained, which has enabled a much better understanding of its ecophysiology. This mini‐review summarizes recent developments in our understanding of Fe transport in higher plants with particular emphasis on crops in the context of major agronomically important abiotic stresses. It also highlights outstanding questions on the regulation of Fe homeostasis and lists potentially useful genes/regulatory pathways that may be useful for subsequent crop improvement under the stresses discussed through either conventional or transgenic approaches.

Barley preferentially activates strategy-II iron uptake mechanism under iron deficiency

“…Although a previous study reported more severe phenotypes under longer Fe deprivation (Erenoglu et al, 2000), results of this current study demonstrate that just five days were sufficient to elicit clear deficiency symptoms in barley leaves. This aligns with research indicating a direct correlation between treatment duration and chlorosis severity in Fe-sensitive cultivars (Bandyopadhyay & Prasad, 2021;Martín-Barranco et al, 2021). Thus, Tarm-92 emerges as highly sensitive to Fe deficiency, exhibiting significant impairments even after a shortterm deprivation.…”

“…DMA is converted to mugineic acid (MA) by IRON DEFICIENCY SPECIFIC CLONE3 (IDS3), which functions as a dioxygenase in barley roots (Kobayashi et al, 2001). Nine MAs have been identified so far in rye and barley (Bandyopadhyay & Prasad, 2021). They are released from plant roots to the rhizosphere as PS via TRANSPORTER OF MA1 (TOM1) (Nozoye et al, 2011), forming a complex with insoluble Fe 3+ in the soil, and then they are taken up into the root epidermis by specific oligopeptide transporters such as YELLOW STRIPE1 (YS1) in Zea mays and YELLOW STRIPE-LIKE15 (YSL15) in Oryza sativa (Aksoy et al, 2018;Rai et al, 2021).…”

Genome-Wide Identification of 2-Oxoglutarate and Fe (II)-Dependent Dioxygenase (2ODD-C) Family Genes and Expression Profiles under Different Abiotic Stresses in Camellia sinensis (L.)

“…Stress-induced DELLA accumulation reduced the bioactive GA content by inhibiting the expression level of GA3ox , increased the activities of reactive oxygen species (ROS) detoxification enzymes (catalases and Cu/Zn-superoxide dismutases) and reduced the ROS accumulation in plants [ 53 , 54 ]. In addition, previous studies reported that iron-containing enzymes (superoxide dismutase, catalase, and glutathione peroxidase) were involved in the detoxification of ROS [ 55 , 56 ], and iron deficiency is believed to be dependent on the type and quantity of mugineic acid [ 57 ]. A functional annotation showed that the orthologous genes of Cs2ODD-C36 in O. sativa was IDS3 (Os07g07410) encoding 2′-deoxymugineic-acid 2′-dioxygenase, which was involved in the formation of mugineic acids [ 58 ].…”

Dissolution kinetics of citrate coated CoFe2O4nanoparticles in soil solution

“…It is an essential nutrient for plants and animals; 1 however, crop species struggle for Fe nutrition, the reason being the low Fe availability for plants. 2 Fe bioavailability is strongly dependent on chemical reactions with soil components. 3 Alternatively, Co has been described as a beneficial element, which means that low concentrations (0.01 to 10 mg kg −1 ) stimulate plant growth and yield, improve drought, salt, and heavy metal resistance, inhibit ethylene biosynthesis, and promote nitrogen fixation by increasing the number of nodules in legumes.…”