Physiological Regulation Associated with Differential Tolerance to Iron Deficiency in Soybean

Abstract

Iron deficiency has become a yield‐limiting factor in many agricultural areas. This study was conducted to elucidate the relationship between physiological traits and soybean [Glycine max (L.) Merr.] tolerance in the presence of different FeEDTA concentrations. Two hydroponic experiments using prescreened Fe‐efficient (FeE) and Fe‐inefficient (FeI) soybean genotypes were performed in 2014 and 2015, respectively. Various chlorophyll fluorescence parameters, antioxidant enzyme activities, and the dry weight of the plants were determined and analyzed by canonical correlation analysis, stepwise regression, and logistic equation. The effective quantum yield of photosystem II (PSII) (PhiPSII), maximal photochemical efficiency of PSII (Fv/Fm), superoxide dismutase (SOD), and peroxidase (POD) activity of the FeE genotypes were significantly higher than those of the FeI genotypes (P < 0.05). High catalase (CAT) and POD activities could improve photoprotection and PhiPSII under Fe deficiency. High POD and CAT activities and high Fv/Fm are conducive to increasing the chlorophyll content of E genotypes, and high CAT activity and longer ∆t are also conducive to increasing dry matter accumulation in FeE genotypes under Fe deficiency. In particular, in the presence of 0.02 mM FeEDTA, FeE genotypes exhibit higher PhiPSII, electron transport rate (ETR), and Fv/Fm values as well as higher SOD, POD, and CAT activities than FeI genotypes. Moreover, FeE genotypes show greater dry matter accumulation because of the longest ∆t in the presence of 0.02 mM FeEDTA. Thus, FeE genotypes have stronger tolerance to Fe deficiency because of their higher antioxidant, photochemical, and photoprotection abilities as well as their increased dry matter accumulation resulting from their longer ∆t in the presence of 0.02 mM FeEDTA.

Understanding the Role of the Antioxidant System and the Tetrapyrrole Cycle in Iron Deficiency Chlorosis

“…However, this definition still lacks information on other factors that could contribute to this trait and recent studies have shown the importance of physiological [7,35] and molecular [36] mechanisms in the Fe efficiency trait of soybean plants. Meanwhile, other studies reported an induction of oxidative stress related reactions when Fe is unavailable for plant uptake and mobilization, since this nutrient is essential for a vast number of biological processes [37,38,39]. Plus, it has been shown that Fe uptake and tetrapyrrole biosynthesis are co-regulated [40].…”

The Ionome of a Genetically Diverse Set of Wild Soybean Accessions

“…This correlation is expected, given the essential role S‐containing amino acids play in protein synthesis and function. When S content is expressed on the basis of total protein, the correlation of S with protein drops to 0.2 as expected, but its correlation with methionine, cysteine, and cysteine + methionine increases to 0.53, 0.57, and 0.60, respectively (Krishnan et al, 2012; Zhao et al, 2018). Given the high heritability of S content, the progeny of wild accessions that are high in both S and protein may have improved S‐containing amino acid composition.…”

“…For example, Mo is required for N 2 reduction in the legume nodules, and Ni and Fe are cofactors in ureases and hydrogenases that are involved in N metabolism in the nodule (Lavres et al, 2016; Weisany et al, 2013). Photosynthesis requires Fe and Mn in in the photosystem reaction centers (Semin et al, 2018; Zhao et al, 2018). In the case of food crops such as soybean, seed components are sources of mineral nutrition for the livestock and humans that consume the meal.…”

Biodiversity within Medicago truncatula genotypes toward response to iron deficiency: Investigation of main tolerance mechanisms

“…The major impact of ROS accumulation in plants is the disruption of the integrity of cell membranes (Berni et al, ; Zhao et al, ). In our case, the electrolyte leakage was stimulated by Fe deficiency.…”

“…The major impact of ROS accumulation in plants is the disruption of the integrity of cell membranes (Berni et al, 2018;Zhao et al, 2018). In our case, the electrolyte leakage F I G U R E 5 Electrolyte leakage (a), and leave (b) and root (c) malondialdehyde content (MDA), of four genotypes of Medicago truncatula grown in the presence of Fe (C), under iron deficiency (DD) and under induced iron deficiency (ID) during the treatment period (21 days).…”