The researchers studied how a transporter called PLGG1 affects the efficiency of a process called photorespiration in plants. They found that under low light, the transporter doesn't make a big difference, but under high light, plants without this transporter have decreased CO2 assimilation. This happens because the transporter helps with Rubisco activity, a key enzyme in photosynthesis. So, disruptions to this transporter can lead to lower CO2 assimilation in plants.