Volatile communication between Chlamydomonas reinhardtii cells under salt stress

Although it is known that volatile organic compounds (VOCs) can be released by lower plants, their release and ecological functions are not much studied, especially in aquatic systems under abiotic stress. In the present study, we determined the compositions of VOCs released from Chlamydomonas reinhardtii under both neutral (NaCl) and alkali (Na2CO3) salt stresses. Hexanal was the newly released abundant compound under NaCl stress, while we found 3,4-dimethyl-hexane and 5-methyl-2-heptene under Na2CO3 stress. Under both stress conditions, longifolene was the significantly increased compound. When C. reinhardtii cells were exposed to the VOCs from the salt-stressed cells, the cell density was reduced, but the content of chlorophyll, Fv/Fm and antioxidant enzyme activity were increased. This might indicate that those VOCs can transfer stress signal between C. reinhardtii cells and tell the receptor to prepare against reactive oxygen species (ROS) damage ahead of the stress coming.

► We determined the VOCs from C. reinhardtii under both NaCl and Na2CO3 stresses.
► These VOCs reduced the cell density but promoted photosynthesis in normal cells.
► The antioxidant enzyme activity in normal cells was increased by these VOCs.
► The VOCs under salt stresses may transfer stress signal between the cells.