Novel self-compatible lines of Brassica rapa L. isolated from the Japanese bulk-populations.
Self-incompatibility (SI) in Brassicaceae is sporophytically controlled by a single S-locus with multi allelic variety. The male S determinant, SP11/SCR (S-locus protein 11/S-locus cysteine-rich protein), is a small cysteine-rich protein, and the female S determinant, SRK (S-locus receptor kinase), functions as a receptor for SP11 at the surface of stigma papilla cells. Although a few of the following downstream factors in the SP11-SRK signaling cascade have been identified, a comprehensive understanding of the SI mechanism still remains unexplained in Brassicaceae. Analysis of self-compatible (SC) mutants is significant for understanding the molecular mechanism in SI reactions, thus we screened SC lines from a variety of Japanese bulk-populations of B. rapa vegetables. Two lines, TSC4 and TSC28, seem to have disruptions in the SI signaling cascade, while the other line, TSC2, seems to have a deficiency in a female S determinant, SRK. In TSC4 and TSC28, known SI-related factors, i.e. SRK, SP11, MLPK (M-locus protein kinase), THL (thioredoxin-h-like), and ARC1 (arm repeat containing 1), were expressed normally, and their expression levels were comparable with those in SI lines. On a B. rapa genetic linkage map, potential SC genes in TSC4 and TSC28 were mapped on linkage groups A3 and A1, respectively, whereas MLPK, ARC1, and THL were mapped on A3, A4, and A6, respectively. Although potential SC genes of TSC4 and MLPK were on the same linkage group, their positions were apparently independent. These results indicate that the SC genes of TSC4 and TSC28 are independent from the S-locus or known SI-related genes. Thus, the SC lines selected here have mutations in novel factors of the SI signaling cascade, and they will contribute to fill pieces in a signal transduction pathway of the SI system in Brassicaceae.
Isokawa
Sachiyo
S
Laboratory of Plant Reproductive Genetics, Graduate School of Life Sciences, Tohoku University.
Osaka
Masaaki
M
Shirasawa
Akira
A
Kikuta
Rina
R
Komatsu
Satoshi
S
Horisaki
Atsushi
A
Niikura
Satoshi
S
Takada
Yoshinobu
Y
Shiba
Hiroshi
H
Isogai
Akira
A
Takayama
Seiji
S
Suzuki
Go
G
Suwabe
Keita
K
Watanabe
Masao
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000235:genetics; D029688:Brassica napus / Q000235:genetics; D029741:Brassica rapa / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D017931:DNA Primers; D018506:Gene Expression Regulation, Plant; D007564:Japan; D008969:Molecular Sequence Data; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014675:Vegetables / Q000201:enzymology / Q000235:genetics
D017931:DNA Primers; D010940:Plant Proteins; D011494:Protein Kinases; C079832:S-receptor kinase