1. Functional Analysis of M-Locus Protein Kinase Revealed a Novel Regulatory Mechanism of Self-Incompatibility in Brassica napus L.
- Author
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Chen F, Yang Y, Li B, Liu Z, Khan F, Zhang T, Zhou G, Tu J, Shen J, Yi B, Fu T, Dai C, and Ma C
- Subjects
- Amino Acid Sequence, Base Sequence, Brassica napus genetics, CRISPR-Cas Systems genetics, Gene Editing, Gene Expression Regulation, Plant, Mutation genetics, Organ Specificity genetics, Phylogeny, Plants, Genetically Modified, Pollination, Protein Isoforms chemistry, Protein Isoforms genetics, Protein Isoforms metabolism, Protein Kinase C chemistry, Protein Kinase C genetics, RNA Interference, RNA, Messenger genetics, RNA, Messenger metabolism, Brassica napus enzymology, Brassica napus physiology, Protein Kinase C metabolism, Self-Incompatibility in Flowering Plants physiology
- Abstract
Self-incompatibility (SI) is a widespread mechanism in angiosperms that prevents inbreeding by rejecting self-pollen. However, the regulation of the SI response in Brassica napus is not well understood. Here, we report that the M-locus protein kinase ( MLPK ) BnaMLPKs , the functional homolog of BrMLPKs in Brassica rapa , controls SI in B. napus . We identified four paralogue MLPK genes in B. napus , including BnaA3.MLPK , BnaC3.MLPK , BnaA4.MLPK , and BnaC4.MLPK . Two transcripts of BnaA3.MLPK , BnaA3.MLPKf1 and BnaA3.MLPKf2 , were generated by alternative splicing. Tissue expression pattern analysis demonstrated that BnaA3.MLPK , especially BnaA3.MLPKf2 , is highly expressed in reproductive organs, particularly in stigmas. We subsequently created RNA-silencing lines and CRISPR/Cas9-induced quadruple mutants of BnaMLPKs in B. napus SI line S-70. Phenotypic analysis revealed that SI response is partially suppressed in RNA-silencing lines and is completely blocked in quadruple mutants. These results indicate the importance of BnaMLPKs in regulating the SI response of B. napus . We found that the expression of SI positive regulators S-locus receptor kinase ( SRK ) and Arm-Repeat Containing 1 ( ARC1 ) are suppressed in bnmlpk mutant, whereas the self-compatibility (SC) element Glyoxalase I ( GLO1 ) maintained a high expression level. Overall, our findings reveal a new regulatory mechanism of MLPK in the SI of B. napus.
- Published
- 2019
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