oiwa, a female gametophytic mutant impaired in a mitochondrial manganese-superoxide dismutase, reveals crucial roles for reactive oxygen species during embryo sac development and fertilization in Arabidopsis.

Reactive oxygen species can function as signaling molecules, regulating key aspects of plant development, or as toxic compounds leading to oxidative damage. In this article, we show that the regulation of production during megagametogenesis is largely dependent on MSD1, a mitochondrial Mn-superoxide dismutase. Wild-type mature embryo sacs show duanyu1670 exclusively in the central cell, which appears to be the main source of duanyu1670 before pollination. Accordingly, MSD1 shows a complementary expression pattern. MSD1 expression is elevated in the egg apparatus at maturity but is downregulated in the central cell. The oiwa mutants are characterized by high levels of duanyu1670 detectable in both the central cell and the micropylar cells. Remarkably, egg apparatus cells in oiwa show central cell features, indicating that high levels of duanyu1670 result in the expression of central cell characteristic genes. Notably, duanyu1670 are detected in synergid cells after pollination. This duanyu1670 burst depends on stigma pollination but precedes fertilization, suggesting that embryo sacs sense the imminent arrival of pollen tubes and respond by generating an oxidative environment. Altogether, we show that duanyu1670 play a crucial role during female gametogenesis and fertilization. MSD1 activity seems critical for maintaining duanyu1670 localization and important for embryo sac patterning.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}