Phosphoproteomic and physiological analysis revealed 6-benzyladenine improved the operation of photosynthetic apparatus in waterlogged summer maize

Summer maize suffers severe yield losses due to waterlogging, threatening food security. Application of 6-benzyladenine (6-BA) can modify protein phosphorylation status, and increase plant tolerance to waterlogging. However, little is known regarding the functional roles of 6-BA-mediated phosphorylation events in regulating plant stress tolerance. Therefore, we conducted an experiment involving three treatments (control (CK), waterlogging at the third leaf stage for 6 days (V3-6), and application of 100 mg L-1 6-BA after waterlogging (V3-6-B)) to probe the impact of 6-BA on leaf phosphoproteome of waterlogged summer maize. Our results demonstrated that waterlogging affected the reversible phosphorylation of proteins that participated in chloroplast movement and differentiation as well as photoreaction and carbon fixation processes. However, application of 6-BA significantly mitigated the waterlogging effects on the phosphorylation level of these proteins. Accordingly, the chloroplast ultrastructure and photosynthetic performances of waterlogged summer maize were improved. These results indicated that application of 6-BA mediated extensive phosphorylation events to improve the absorption and dissipation of light energy, the assimilation and metabolism of carbon, and the ultrastructure of chloroplast, thus increasing the photosynthesis rate of waterlogged summer maize. consequently, the plant growth and grain yield of waterlogged summer maize were improved by application of 6-BA.

Automated summary

The research shows that the application of 6-BA can enhance the tolerance of summer maize to waterlogging, improve chloroplast ultrastructure and photosynthetic performance, ultimately increasing photosynthesis rate and grain yield.