Vietnamese scientists were able to bring forward transgenic lines of an elite Vietnamese rice variety that exhibited resistance against bacterial leaf blight (BLB) disease using CRISPR-Cas9. Their work supports the potential diversity of Transcription-Activator-Like Effectors (TALEs) in Vietnamese Xanthomonas oryzae pv. Oryzae (Xoo) population, the causal agent of BLB.

The scientists used the TBR225 rice variety, a popular Vietnamese rice that is, unfortunately, highly susceptible to BLB that leads to high yield loss. Their research aimed to introduce BLB resistance to the TBR225 variety by focusing on the OsSWEET14 gene that belongs to a gene family that encodes sugar transporters. This gene behaves as a susceptibility gene to BLB with other Clade III members when induced by Asian Xoo TALEs which is necessary for the disease.

The researchers produced nine TBR225 mutant lines whose OsSWEET14 promoter had mutations in its TaIF TALEs DNA target sequences. This was obtained using CRISPR-Cas9. T0 and T1 generations were shown to have stably inherited the mutation. The T2 generation was compared with the wild TBR225 type and was found not to be significantly different in terms of agronomic traits. Moreover, one of the T2 lines displayed decreased OsSWEET14 expression and significantly reduced susceptibility to one Vietnamese Xoo strain and complete resistance to another Xoo strain. Their research shows that CRISPR-Cas9 editing can be used to develop improved BLB resistance to a commercial Vietnamese rice variety.

Learn more about the details of the study by reading the full paper in PLOS.