Vitamin-B12 auxotrophy of two bacteria resolved by complementary biosynthesis thru B12 and building block crossfeeding

Two bacterial B12 auxotrophes complement their lacking genetic capabilities by exchanging vitamin B12 building blocks. To better understand this bacterial interaction we grew both isolates in co-culture without the addition of B12, monitored growth over time and withdraw samples for transcriptome sequencing. The transcriptome of both bacteria in co-culture were compared to transcriptomes of the respective mono-cultures when B12 was amended. Overall, a large share of significantly upregulated genes were either directly or indirectly associated to the B12 pathway or uptake system and elucidated the B12-building block exchange mechanism between the two bacterial organisms.