CO2is a key constituent of the plant growth-promoting volatiles generated by bacteria in a sealed system

Key message Plant growth is greatly inhibited in tightly sealed Petri dishes for lack of CO2. Bacteria which co-cultured with plant can produce CO(2)to promote plant growth in sealed systems. Bacteria produce a wide variety of volatiles, some of which can support and others can damage plant growth. It is a controversial issue whether CO(2)or other bacterial volatile compounds promote plant growth in sealed systems. CO(2)is critical for photosynthesis. Here, we show that CO(2)is a key constituent of the plant growth-promoting volatiles generated by bacteria in a sealed system. We revealed that the growth ofArabidopsisseedlings in an airtight container was retarded due to insufficient supply of the CO2. When either CO(2)was introduced into the container, or the seedlings were co-cultured along with certain bacterial species, the plants' growth was restored. Conclusion: The benefit of co-culturing was largely due to the CO(2)generated by respiration of the bacteria.