Resistance spectrum of genome edited rice lines against all the known SWEET inducing TALE variants of Xanthomonas oryzae pv. oryzae strains found in the Philippines.

The sugar transporter genes (OsSWEET11, OsSWEET13 and OsSWEET14) are well-characterized susceptibility genes targeted by TAL effectors (TALE) of Xanthomonas oryzae pv. oryzae(Xoo), the causal agent of bacterial blight disease. We have generated mutant rice lines using multiplex CRISPR/Cas9 technology to alter specific promoter sequences (EBEs, effector binding elements) of the three SWEET genes that would potentially inhibit TAL-mediated disease susceptibility in rice. The EBE mutant alleles range from 1bp indel up to 62 bp deletion that abolish the binding of PthXo1, PthXo2, TalC, and PthXo3/AvrXa7 TALEs. Previously, we published thirteen quintuple mutant rice lines harboring different combinations of these edited EBE alleles which showed resistance against three Philippine Xoo (PXO) strains: PXO99 (Race 6), PXO339 (Race 9a), and PXO86 (Race 2). The three strains tested harbor an allele of PthXo1 targeting OsSWEET11, PthXo2 targeting OsSWEET13, and AvrXa7 targeting OsSWEET14, respectively. Here, we extended the testing of edited lines with all known variants of SWEET-targeting TALE present in PXO strains. We also explored the possibility of pathogen escape in SWEET mutant alleles to identify the most durable variants. Our results provide insight on future gene editing and editing event selection strategies to confer durable resistance of not only bacterial leaf blight but also other diseases that share the same mechanism.