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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chlorophyll-protein complexes and electron transport activities were measured during iron nutrition-mediated chloroplast development in sugar beet (Beta vulgaris L. cv F58-554H1). Results showed that the chlorophyll-protein complexes associated with the reaction centers of photosystem I (CP1) and photosystem II (CPa) and the electron transport activities of these two photosystems per leaf area increased rapidly during the first 24 to 48 hours of iron resupply to iron-deficient sugar beet plants. Bulk chlorophyll and the amounts of light-harvesting chlorophyll-proteins increased after a lag period of 24 hours. The changes in chlorophyll-proteins with time were apparently the cause of an initial increase, then decrease, in the chlorophyll a/b ratio during iron resupply. There was evidence that iron deficiency diminished photosystem I more than photosystem II. We propose that there are two distinct phases in iron nutrition-mediated chloroplast development: (a) the commencement of the synthesis of the lipid matrix of the thylakoid membrane, including a fully functioning electron transport (and photosynthetic) system, during the first 24 hours of iron resupply; and (b) after 24 to 48 hours, the formation of the bulk of the thylakoid proteins, including the light-harvesting chlorophyll-proteins with which the large increase in total chlorophyll is associated.
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PMID:Chlorophyll-Proteins and Electron Transport during Iron Nutrition-Mediated Chloroplast Development. 1666 33

Rice (Oryza sativa) is one of the staple foods of the world. Iron (Fe) deficiency is a major abiotic stress factor that contributes world-wide to losses in crop yield and decline in nutritional quality. As cofactor for many enzymes and proteins, iron is an essential element. It plays a pivotal role in chlorophyll (Chl) biosynthesis, and iron deficiency may result in decreased Chl production and, thus, reduced photosynthetic capacity. Photosystem I (PSI) is a prime target of iron deficiency because of its high iron content (12 Fe per PS). To understand the protein level changes in the light-harvesting complex (LHC) of PSI (LHCI) under iron deficiency, rice seedlings were grown in Hoagland's nutrient medium with and without Fe. Chlorophyll content and photosynthetic efficiency decreased under iron deficiency. Protein gel blots probed with antibodies against the PSI core and Lhca 1-4 proteins revealed that the core subunits PsaA and PsaB remained stable under iron deficiency, whereas PsaC and PsaD decreased by about 50%, and PsaE was completely degraded. Among the LHCI subunits, Lhca1 and Lhca2 decreased by 40 and 50%, respectively, whereas Lhca3 and Lhca4 were completely degraded. We propose that the dissociation of LHCI subunits may be due to increased levels of reactive oxygen species, which is suggested by the increased activity of superoxide dismutase.
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PMID:Differential degradation of photosystem I subunits under iron deficiency in rice. 2244 51