Three types of genes underlying the game-tophyte factor1 locus cause unilateral cross incompatibility in maize

Authors: WANG, YUEBIN - Huazhong Agricultural University; LI, WENQIANG - Huazhong Agricultural University; WANG, LUXI - Huazhong Agricultural University; YAN, JIALI - Huazhong Agricultural University; LU, GANG - Huazhong Agricultural University; YANG, NING - Huazhong Agricultural University; XU, JIETING - Huazhong Agricultural University; WANG, YUQING - Huazhong Agricultural University; GUI, SONGTAO - Huazhong Agricultural University; CHEN, GENGSHEN - Huazhong Agricultural University; LI, SHUYAN - Huazhong Agricultural University; WU, CHENGXIU - Huazhong Agricultural University; GUO, TINGTING - Huazhong Agricultural University; XIAO, YINGJIE - Huazhong Agricultural University; Warburton, Marilyn; FERNIE, ALISDAIR - Max Planck Institute Of Molecular Plant Physiology; DRESSELHAUS, THOMAS - University Of Regensburg; YAN, JIANBING - Huazhong Agricultural University

Submitted to: Nature Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2022
Publication Date: 8/3/2022
Citation: Wang, Y., Li, W., Wang, L., Yan, J., Lu, G., Yang, N., Xu, J., Wang, Y., Gui, S., Chen, G., Li, S., Wu, C., Guo, T., Xiao, Y., Warburton, M.L., Fernie, A.R., Dresselhaus, T., Yan, J. 2022. Three types of genes underlying the game-tophyte factor1 locus cause unilateral cross incompatibility in maize. Nature Communications. 13(4498):1-12. https://doi.org/10.1038/s41467-022-32180-9.
DOI: https://doi.org/10.1038/s41467-022-32180-9

Interpretive Summary: Some types of corn can't pollinate each other, a phenomenon called unilateral cross incompatibility. There is one place on one of the chromosomes of corn that is known to be important for this trait. The current study found that there are actually 7 genes close together on the chromosome that together cause unilateral cross incompatibility, and that these 7 genes create three types of proteins that determine if a pollen grain will grow through the silk and reach the egg of the plant it is pollinating. The implications of this phenomenon on the evolution and breeding of corn is discussed.

Technical Abstract: Maize unilateral cross incompatibility (UCI) occurs between popcorn and dent corn and is caused by the Gametophyte factor1 (Ga1) locus. However, the underlying genetic basis has remained unclear for decades. We report here seven different linked genes, encoding three types of proteins, affecting UCI. These include five pollen-expressed PECTIN METHYLESTERASE (PME) genes (PMEs-m), one silk-expressed PME gene (PME3), and one silk-expressed gene encoding a cysteine-rich protein (CRP1). While PMEs-m determine pollen compatibility, PME3 confers silk incompatibility, and CRP1 promotes pollen tube growth and breaks the incompatibility effect of PME3. The three types of genes independently regulate the growth of pollen tubes, ultimately demonstrating a genetic model balanced between antagonistic and synergistic effects governing the UCI system. This model furthers our understanding of the complex regulation of cross incompatibility, reproductive isolation, and ultimately, the evolution of new species.