Abstract:

Zinc (Zn) is an essential micronutrient for plants and humans. Zn deficiency is common in many rice fields that reduces yield and grain zinc content (GZC). To speed up breeding for improved GZC and Zn deficiency tolerance (ZDT) it is important to identify key genes regulating Zn homeostasis. In this study, we reported that a member of the Ser/Thr protein phosphatase family, LOC_Os07g48840 (named as OsGZ7), contributes to ZDT and GZC in rice. The expression of OsGZ7 in root and shoot is inhibited by Zn deficiency and toxicity, but induced by Fe, Mn and Cu deficiency, and Cd toxicity. OsGZ7 was localized in the cytoplasm. OsGZ7 was expressed in all tissues during the tillering, flowering, and grain filling stages, particularly in leaf blade and leaf sheath. At the seedling stage, knockout of OsGZ7 enhanced ZDT and increased the accumulation of Zn in roots and shoots. At the maturity stage, knockout of OsGZ7 enhanced GZC, while overexpression of OsGZ7 reduced GZC. RNA-seq analysis suggested OsGZ7 may regulate Zn homeostasis by affecting metal binding, hormone signal transduction and oxidoreductase. Taken together, our study indicated that OsGZ7 contributes to ZDT and Zn accumulation in rice.

Key words:  , OsGZ7, rice, zinc accumulation, zinc deficiency tolerance