14 research outputs found
Analysis of tomatoes showing iron deficiency symptoms in winter under heavy fruit load
Declines in crop productivity that are thought to be due to iron deficiency have been reported even on non-calcareous-alkaline soils. For example, tomatoes exhibit iron deficiency-like symptoms (yellowing of new leaves) if the fruit load is heavy during winter. The objective of this study is to investigate the relationship between fruit load, low temperatures, low sunlight, and iron deficiency, and to explore the possibility of increasing productivity with iron-containing fertilizers. Results of an investigation of the farms experiencing iron deficiency-like symptoms in winter showed low iron concentrations and elevated expression of iron deficiency-inducible genes in yellowing leaves. To investigate the effects of heavy fruit load on iron nutrition, plants were grown in three groups: those with a medium number of fruits per truss (MED), a high number of fruits (heavy fruit load; HEAVY), and a high number of fruits with additional iron fertilization (++Fe). The SPAD leaf-color value of the new leaves and weight of the lower leaves in winter were in the order of HEAVY < ++Fe < MED. In all groups, the iron concentrations in the upper leaves in January were lower than those in October and March. RNA-seq analysis showed that the expression of genes involved in iron absorption was suppressed in the roots in January, which may have contributed to iron deficiency in winter. These results suggest that one of the factors limiting the productivity of tomatoes in winter with heavy fruit load is iron, and that productivity can be restored by iron materials.</p
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Analysis of the spatial expression patterns of rice iron deficiency-responsive element-binding factors IDEF1 and IDEF2
Iron (Fe) is critical for plant growth. Under conditions of low Fe availability, rice plants induce genes involved in Fe uptake and utilization. Recently, we identified the iron-deficiency-responsive cis-acting elements IDE1 and IDE2, which are bound in a specific manner by IDE-binding factors 1 and 2 (IDEF1 and IDEF2, respectively). IDEF1 and IDEF2 regulate genes related to the Fe-deficiency response. In the present study, we examined the spatial expression patterns of IDEF1 and IDEF2 during the germination, vegetative, and seed-maturation stages by assessing their localization in IDEF1 and IDEF2 promoter–GUS transgenic rice lines. During germination, IDEF1 and IDEF2 were expressed in the endosperm and embryo. In hydroponic culture experiments, the expression patterns of IDEF1 and IDEF2 were similar under both Fe-deficient and Fe-sufficient conditions during the vegetative stage. In leaves, IDEF1 expression was observed in mesophyll cells and in small vascular bundles, whereas IDEF2 was highly expressed in vascular bundles. In root sections, IDEF1 and IDEF2 were highly expressed in secondary roots and inside vascular bundles. IDEF1 was also expressed in pollen from flowers before and after anthesis, in the ovary after fertilization, and in the embryo during seed maturation. IDEF2 was expressed in flowering stage pollen, in immature seeds just after flowering, and in the dorsal vascular region during the late maturation stage. The spatial expression patterns of IDEF1 and IDEF2 partially overlapped with their target genes