Synthetic photorespiratory bypass more stably increases potato yield per plant by improving photosynthesis.

Abstract

The bioengineering of photorespiration has emerged as a key target for improving photosynthesis and crop yield. In our previous study, two photorespiratory bypasses, GOC and GCGT, were successfully established in rice, and the transgenic plants exhibited increased photosynthesis and yield. However, reduced seed-setting rates were observed in both GOC and GCGT rice. To overcome this bottleneck, we introduced the GOC bypass into potato, as potato is vegetatively reproduced without the need for pollination, unlike rice. After the GOC bypass was successfully established in potato, transgenic plants were tested in field experiments at different locations in China with contrasting climates. Consequently, the yield per plant increased by 21.3%-69.2% for GOC potatoes under normal growth conditions and enhanced by 12.9%-29.9% under adverse environments. GOC potatoes acquired a more stable yield increase than GOC rice. Moreover, the advantages under high light, as noticed earlier for GOC rice, were further verified in this study through various field experiments because the yield increase was obviously higher in GOC potatoes grown in the northern area with high solar radiation than in those grown in the south with relatively lower solar radiation. Mechanistic analyses indicated that photosynthesis increased while photorespiration was suppressed, and much fewer photosynthates accumulated in GOC potatoes. These results demonstrate that the GOC bypass increases yield per plant more stably in potato than in rice, as well as show promising prospects for practical application in improving crop yields, particularly under high-light conditions.