Abstract
Kernel weight is an important yield component in maize that was selected during domestication. Many kernel weight genes have been identified through mutant analysis, and are mostly involved in the biogenesis and functional maintenance of organelles or other fundamental cellular activities. However, only a limited number of loci underlying quantitative variation in kernel weight have been cloned. Here we characterize a maize kernel weight QTL, qKW9 and find that it encodes a DYW motif pentatricopeptide repeat protein involved in C-to-U editing of NdhB, a subunit of the chloroplast NADH dehydrogenase-like complex. In a null qKW9 background, C-to-U editing of NdhB was abolished, and photosynthesis was reduced, suggesting that qKW9 regulates kernel weight by controling the maternal source of photosynthate for grain filling. Characterization of qKW9 highlights the importance of optimizing photosynthesis on maize grain yield production.
Footnotes
One sentence summary: A pentatricopeptide repeat protein exerts quantitative effect on maize kernel weight and size by affecting photosynthesis and grain filling.
Funding information: This work was supported by the National Key Research and Development Program of China (2016YFD0100303), the National Natural Science Foundation of China (31525017, 31961133002), and NSF grant IOS-1546837 to DJ; Juan Huang was sponsored by China Scholarship Council to visit Cold Spring Harbor Laboratory and study in Prof. David Jackson’s lab from March 2018 to March 2019 (File No. 201706760027).
Author Contributions: J.Y. designed and supervised this study. D.J. supervised the study in US side. J.H., G.L., and T. T finished most of the mentioned experiments. Lei. L conducted RNA sequence data analysis. M. S. R. and Jie. L involved in the initial QTL mapping. J.H., G.L. and W. L. performed the field experiments. J.X. and L.J. conducted the transgenic transformation. L.Z. and C.W. performed cytological experiments. Q.Z. constructed the RNA sequencing library and finished the sequencing. J.H., D.B., Q.L., A.F., D.J., and J.Y. contribute a lot of constructive discussions and wrote or revised the manuscript.
Competing financial interests: The authors declare no competing financial interests.