Restriction of iron loading into developing seeds by a YABBY transcription factor safeguards successful reproduction in Arabidopsis.

Iron (Fe) storage in plant seeds is not only necessary for seedling establishment following germination but is also a major source of dietary Fe for humans and other animals. Accumulation of Fe in seeds is known to be low during early seed development. However, the underlying mechanism and biological significance remain elusive. Here, we show that reduced expression of Arabidopsis YABBY transcription factor INNER NO OUTER (INO) increases embryonic Fe accumulation, while transgenic overexpression of INO results in the opposite effect. INO is highly expressed during early seed development, and decreased INO expression increases the expression of NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 1 (NRAMP1), which encodes a transporter that contributes to seed Fe loading. The relatively high embryonic Fe accumulation conferred by decreased INO expression is rescued by the nramp1 loss-of-function mutation. We further demonstrated that INO represses NRAMP1 expression by binding to NRAMP1-specific promoter region. Interestingly, we found that excessive Fe loading into developing seeds of ino mutants results in greater oxidative damage, leading to increased cell death and seed abortion, a phenotype that can be rescued by the nramp1 mutation. Taken together, these results indicate that INO plays an important role in safeguarding reproduction by reducing Fe loading into developing seeds by repressing NRAMP1 expression.

[Statistics of internationally-issued English articles on ophthalmology by mainland Chinese authors during the past 6 years].

OBJECTIVE: To understand and to analyze the overall situation of ophthalmic research articles issued in English internationally by mainland Chinese authors during the past 6 years. METHODS: Using relevant retrieval words to search the articles from the PubMed, the largest database in biology and medical science in the world, and to conduct a statistical analysis. RESULTS: Three hundred and ninety two English ophthalmological articles by mainland Chinese researchers as the first author or first organization were published in 134 periodicals. Most of these organizations were medical universities (as well as their affiliated hospitals) and China Academy of Science. There were 23 journals which published more than 4 articles and there were 25 organizations issued more than 4 articles. CONCLUSIONS: During the past 6 years, there was a significant increase in the number of articles issued internationally by mainland Chinese authors, indicating an enormous progress in the field of ophthalmic research in mainland of China.