Crop Biotech Update

OsABA8ox2 Suppresses Root Elongation and Contributes to Drought Response in Rice

January 8, 2020

Researchers from the Chinese Academy of Agricultural Sciences investigated the function of OsABA8ox in root growth and development and drought response and found that it is a potential genetic target for improvement of rice drought tolerance. The results are released in The Crop Journal.

OsABA8ox encodes abscisic acid (ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. Since the contribution of ABA catabolism in root development remains unclear, the researchers conducted a study using the CRISPR-Cas9 system. Staining analysis showed that OsABA8ox was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was reduced after polyethylene glycol (PEG) treatment and increased after rehydration, which imply that OsABA8ox2 is a drought-responsive gene.

CRISPR-Cas9 OsABA8ox2 knockout exhibited increased drought-induced ABA and indole-3-acetic acid build up in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture beneficial to drought tolerance. Overexpression of the gene resulted in suppressed root elongation and increased stomatal conductance and transpiration rate.

Based on the findings, OsABA8ox2 knockout significantly enhances rice drought tolerance.

Read more findings in The Crop Journal.

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