Rice ASR1 regulates sugar levels and participates in sugar signaling in roots

Abstract

The ASR gene is found in various plant species. Although ASR is also expressed in sink tissues, most functional studies on this gene have been performed in source leaves. Here, we report that OsASR1 is involved in the abscisic acid (ABA) response via regulation of sugar levels in the roots. Overexpression of OsASR1 altered root sugar content by increasing fructose levels and decreasing sucrose levels. Moreover, the transcript levels of sugar transporters and sucrose metabolism-related genes were altered in the roots of OsASR1-OX lines. Upon ABA treatment, an additional increase in the glucose and fructose levels was observed in the roots of OsASR1-OX lines compared with ABA-treated NT controls and untreated OsASR1-OX lines. Compared with NT control, the root growth of OsASR1-OX lines was more strongly inhibited by 10 % glucose. Our results suggest that OsASR1 plays an important role in the ABA response and sugar signaling in the roots.