BnaC9.SMG7b Functions as a Positive Regulator of the Number of Seeds per Silique in Brassica napus by Regulating the Formation of Functional Female Gametophytes.
Number of seeds per silique (NSS) is an important determinant of seed yield potential in Brassicaceae crops, and it is controlled by naturally occurring quantitative trait loci. We previously mapped a major quantitative trait locus, qSS.C9, on the C9 chromosome that controls NSS in Brassica napus. To gain a better understanding of how qSS.C9 controls NSS in B. napus, we isolated this locus through a map-based cloning strategy. qSS.C9 encodes a predicted small protein with 119 amino acids, designated as BnaC9.SMG7b, that shows homology with the Ever ShorterTelomere1 tertratricopeptide repeats and Ever Shorter Telomere central domains of Arabidopsis (Arabidopsis thaliana) SUPPRESSOR WITH MORPHOGENETIC EFFECTS ON GENITALIA7 (SMG7). BnaC9.SMG7b plays a role in regulating the formation of functional female gametophyte, thus determining the formation of functional megaspores and then mature ovules. Natural loss or artificial knockdown of BnaC9.SMG7b significantly reduces the number of functional ovules per silique and thus, results in decreased seed number, indicating that qSS.C9 is a positive regulator of NSS in B. napus. Sequence and function analyses show that BnaC9.SMG7b experiences a subfunctionalization process that causes loss of function in nonsense-mediated mRNA decay, such as in Arabidopsis SMG7. Haplotype analysis in 84 accessions showed that the favorable BnaC9.SMG7b alleles are prevalent in modern B. napus germplasms, suggesting that this locus has been a major selection target of B. napus improvement. Our results represent the first step toward unraveling the molecular mechanism that controls the natural variation of NSS in B. napus.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Shipeng
S
Li
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Lei
L
Chen
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Liwu
L
Zhang
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Xi
X
Li
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Ying
Y
Liu
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Zhikun
Z
Wu
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Faming
F
Dong
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Lili
L
Wan
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Kede
K
Liu
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.) dfhong@mail.hzau.edu.cn.
Dengfeng
http://orcid.org/0000-0001-9460-219X
D
Hong
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China (S.L., L.C., L.Z., X.L., Y.L., Z.W., F.D., L.W., K.L., D.H., G.Y.); andCollege of Crop Science, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China (L.Z.).
Guangsheng
G
Yang
D000483:Alleles; D000595:Amino Acid Sequence; D029688:Brassica napus / Q000235:genetics / Q000502:physiology*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular / Q000379:methods; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D006239:Haplotypes; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D059365:Nonsense Mediated mRNA Decay / Q000235:genetics; D056771:Ovule / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics / Q000502:physiology*; D017386:Sequence Homology, Amino Acid
D010940:Plant Proteins