| Literature DB >> 33193207 |
Sara C D Carpenter1, Prashant Mishra2, Chandrika Ghoshal2, Prasanta K Dash2, Li Wang1, Samriti Midha3, Gouri S Laha4, Jagjeet S Lore5, Wichai Kositratana6, Nagendra K Singh2, Kuldeep Singh7, Prabhu B Patil3, Ricardo Oliva8, Sujin Patarapuwadol6, Adam J Bogdanove1, Rhitu Rai2.
Abstract
The rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) constrains production in major rice growing countries of Asia. Xoo injects transcription activator-like effectors (TALEs) that bind to and activate host "susceptibility" (S) genes that are important for disease. The bacterial blight resistance gene xa5, which reduces TALE activity generally, has been widely deployed. However, strains defeating xa5 have been reported in India and recently also in Thailand. We completely sequenced and compared the genomes of one such strain from each country and examined the encoded TALEs. The two genomes are nearly identical, including the TALE genes, and belong to a previously identified, highly clonal lineage. Each strain harbors a TALE known to activate the major S gene SWEET11 strongly enough to be effective even when diminished by xa5. The findings suggest international migration of the xa5-compatible pathotype and highlight the utility of whole genome sequencing and TALE analysis for understanding and responding to breakdown of resistance.Entities:
Keywords: SWEET genes; bacterial blight of rice; single molecule real-time sequencing; susceptibility genes; transcription activator-like effectors
Year: 2020 PMID: 33193207 PMCID: PMC7610140 DOI: 10.3389/fmicb.2020.579504
Source DB: PubMed Journal: Front Microbiol ISSN: 1664-302X Impact factor: 5.640
Figure 1Synteny between IX-280 and SK2-3 genomes and comparison of their tal genes. (A) Progressive Mauve alignment of the chromosomes of IX-280 and SK2-3 and other representative Xoo strains. (B) Map of the tal genes in IX-280 and SK2-3. Black arrows represent full-length tal genes, gray arrows truncTALE genes, and white arrows tal pseudogenes. Solid lines connect tal genes with >99% nucleotide identity and identical RVD sequence, and dotted lines connect less similar but clearly orthologous genes.
Figure 2Positions of IX-280 and SK2-3 on a clonal lineage tree derived from genomic sequences of 100 Indian Xoo strains and other Xoo strains from Asia. Lineages are block shaded in different colors. IX-280 and SK2-3 (blue font) are in lineage L-I.
Figure 3RVD sequences of IX-280 and SK2-3 TALEs. RVDs in bold are different in PXO99A orthologs. A dagger indicates a truncTALE. The underlined RVD of Tal2a resides in a truncated (28 aa) repeat. Lower case italicized RVDs are untranslated following a frameshift. An asterisk indicates that the second amino acid in the RVD is absent, resulting in a 33 aa repeat.
Figure 4Induction of SWEET11, TFX1, and TFIIAγ1 by IX-280 in IR24 vs. IRBB5 plants. Shown is fold induction in IR24 (Xa5) and IRBB5 (xa5) at 24–27 h after inoculation by syringe infiltration of IX-280 relative to mock (water)-inoculated leaves, measured by qRT-PCR. Each bar represents the mean of three replicates. Error bars represent standard deviation.
The IX-280 and SK2-3 genome assemblies.
| IX-280 | SK2-3 | |
|---|---|---|
| Chromosome | 4,963,593 bp | 4,934,446 bp |
| Plasmid | 42,975 bp | - |
| Final coverage | 164.0x | 156.4x |
| % Mapped reads | 94.6% | 92.0% |
| Annotated genes | 5,041 | 4,926 |
| Annotated IS elements | 411 | 407 |
| Annotated transposases | 730 | 698 |
| 17 | 17 |