Faculty of Agriculture, Kagawa University, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
Faculty of Agriculture, Kagawa University, Miki-cho, Kita-gun, Kagawa 761-0795, Japan; Faculty of Agriculture Kamphaeng-saen, Kasetsart University Kamphaeng-saen Campus, Nakorn Pathom, 73140, Thailand.
J Plant Physiol. 2020 Sep;252:153247. doi: 10.1016/j.jplph.2020.153247. Epub 2020 Aug 3.
In the nitrogen fixation process, iron plays a vital role by being part of many symbiotic proteins, such as nitrogenase and leghemoglobin, in an active symbiosis. Excess or insufficient iron in active nitrogen fixation negatively affects the entire process. In Lotus japonicus nodules, ferritin is expressed at the initial stages of nodule development and increases at the nodule senescence stage to mobilize iron release during that stage. In this study, we investigated the effects of overexpressing and suppressing ferritin on nitrogen fixation. Acetylene reduction activity revealed that nitrogen fixation is affected by the overexpression of ferritin at high iron concentrations, but at low iron concentrations, higher nitrogen fixation was observed in ferritin-suppressed plants. qRT-PCR data indicated that suppression of ferritin in nodules induces antioxidant genes, such as superoxide dismutase, dehydroascorbate reductase and ascorbate peroxidase, to detoxify reactive oxygen species. Our data suggest that suppressing ferritin in the nodules is effective for higher nitrogen fixation under iron deficient conditions. Overaccumulated ferritin in nodule is effective under the higher iron conditions, such as senescence state.
在固氮过程中，铁通过成为许多共生蛋白（如固氮酶和豆血红蛋白）的一部分，在活跃的共生中发挥着至关重要的作用。过量或不足的铁会对整个固氮过程产生负面影响。在百脉根根瘤中，铁蛋白在根瘤发育的初始阶段表达，并在根瘤衰老阶段增加，以在该阶段动员铁释放。在这项研究中，我们研究了过表达和抑制铁蛋白对固氮的影响。乙炔还原活性表明，铁蛋白的过表达会影响固氮，尤其是在高浓度铁的情况下，但在低浓度铁的情况下，铁蛋白抑制的植物中观察到更高的固氮。qRT-PCR 数据表明，在根瘤中抑制铁蛋白会诱导抗氧化基因，如超氧化物歧化酶、脱氢抗坏血酸还原酶和抗坏血酸过氧化物酶，以解毒活性氧。我们的数据表明，在缺铁条件下，抑制根瘤中的铁蛋白对于更高的固氮是有效的。在较高的铁条件下，如衰老状态，过量积累的铁蛋白在根瘤中是有效的。
