A TAL effector-like protein of an endofungal bacterium increases the stress tolerance and alters the transcriptome of the host

• DOI: 10.1073/pnas.2003857117
• Publication Date: 2020-07-07T00:30:02Z
• Authors: Morgan E. Carter; Sara C.D. Carpenter; Zoë E. Dubrow; Mark R. Sabol; Fabio C. Rinaldi; Olga A. Lastovetsky; Stephen J. Mondo; Teresa E. Pawlowska; Adam J. Bogdanove
• Keywords: 0301 basic medicine; 570; Burkholderia; Physiological; 610; Plant Biology; Stress; Microbiology; 03 medical and health sciences; type III secretion; Stress, Physiological; Gene Expression Regulation, Fungal; TAL effector; Genetics; Type III Secretion Systems; 2.2 Factors relating to the physical environment; Rhizopus microsporus; Aetiology; Symbiosis; Transcription Activator-Like Effectors; 0303 health sciences; Biological Sciences; symbiosis; Btl proteins; Fungal; Gene Expression Regulation; 13. Climate action; Infection; Transcriptome; Rhizopus

Symbioses of bacteria with fungi have only recently been described and are poorly understood. In the symbiosis Mycetohabitans (formerly Burkholderia) rhizoxinica fungus Rhizopus microsporus, bacterial type III (T3) secretion is known to be essential. Proteins resembling T3-secreted transcription activator-like (TAL) effectors plant pathogenic encoded in three sequenced spp. genomes. TAL nuclear-localize plants, where they bind activate genes important disease. The Burkholderia TAL-like (Btl) proteins DNA but lack N- C-terminal regions, which harbor their T3 nuclear localization signals, activation domain. We characterized a Btl protein, Btl19-13, found that, despite structural differences, it can nuclear-localize. A btl19-13 gene knockout did not prevent bacterium from infecting fungus, became less tolerant cell membrane stress. Btl19-13 alter plant-based reporter assay, 15 R. microsporus were differentially expressed comparisons both infected wild-type vs. mutant complemented strain. Southern blotting revealed btl 14 diverse isolates. However, banding patterns available sequences suggest variation, phenotype could rescued by different Our findings support conclusion that act on host play varied or possibly genotype-specific roles M. rhizoxinica-R. symbiosis.