Scientists Shed Light on the Role of Abscisic Acid in Rice Disease Resistance

Lesion mimic mutants exhibit spontaneous cell death, thus, can be studied to understand the mechanism of cell death and disease-resistance. Although these mutants have been characterized in rice, the relationship between lesion formation and abscisic acid (ABA) is quite unknown. A team led by Liao Yongxiang from Sichuan Agricultural University in China identified a rice mutant, named lesion mimic mutant9150 (lmm9150). The mutant exhibits spontaneous cell death, enhanced growth, and resistance to rice bacterial and blast diseases.

Researchers found that cell death in the mutant was accompanied with excessive accumulation of hydrogen peroxide. Enhanced disease-resistance and upregulation of defense-related genes were also found to be associated with cell death. ABA levels in the lmm9150 mutant were also significantly reduced. Further analysis revealed a point mutation in the OsABA2 gene, a vital gene for ABA synthesis, in the lmm9150 mutants.

Through CRISPR-Cas9 knockout of OsABA2, the researchers generated gene-edited lines with similar phenotypes to lmm9150, proving that OsABA2 was truly responsible for the lmm9150 mutant.

This data revealed the connection of ABA deficiency to cell death and provided insights into the role of ABA in rice disease-resistance.

For more information, read the article in Frontiers in Plant Science.