title: SS1 (NAL1)- and SS2-Mediated Genetic Networks Underlying Source-Sink and Yield Traits in Rice (Oryza sativa L.).
abstract: Source leaf/sink capacity (SS) traits are important determinants of grain yield (GY) of rice. To understand the genetic basis of the SS relationship in rice, five SS and GY traits of rice were genetically dissected using two reciprocal introgression populations. Seventy-three QTL affecting the SS and GY traits were identified, most of which were detected in one of the parental genetic backgrounds (GBs). Two major QTL at bins 4.7 (SS1) and 3.12 (SS2) were associated consistently with all measured SS and yield traits in both GBs across two contrasting environments. Strong interactions between SS1/SS2 and the detected QTL led us to the discovery of genetic networks affecting the SS and GY traits. The SS1 acted as a regulator controlling two groups of downstream QTL affecting the source leaf width and grain number per panicle (GNP). SS2 functioned as a regulator positively regulating different groups of downstream QTL affecting the source leaf length, GNP, grain weight, and GY. Map-based cloning of SS1 indicates that SS1 is NAL1 involved in polar auxin/IAA transport. Different alleles at NAL1 were apparently able to qualitatively and/or quantitatively control the IAA transport from the apical meristem to different plant tissues and thus regulate those downstream loci/pathways controlling different SS traits of rice. There was a functional allele and a non-functional mutation in the parents at each of the QTL downstream of SS1 or SS2, which were detectable only in the presence of the functional allele of SS1 or SS2. Our results provided direct evidence that SS and yield traits in rice are controlled by complex signaling pathways and suggest further improvement of rice yield potential with enhanced and balanced SS relationships can be achieved by accurately manipulating allelic combinations at loci in the SS1 and SS2 mediated pathways.
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China; Shenzhen Institute for Innovative Breeding, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.
authors.forename: Jian-Long
authors.initials: JL
authors.lastname: Xu
authors.affiliation: Rice Institute of Shenyang Agricultural University/Key Laboratory of Crop Physiology, Ecology, Genetics and Breeding, Ministry of Agriculture, Shenyang 110866, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Tian-Qing
authors.initials: TQ
authors.lastname: Zheng
authors.affiliation: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Xiu-Qin
authors.initials: XQ
authors.lastname: Zhao
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Yan-Ru
authors.initials: YR
authors.lastname: Cui
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Hong-Xuan
authors.initials: HX
authors.lastname: Lin
authors.affiliation: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jia-Yang
authors.initials: JY
authors.lastname: Li
authors.affiliation: Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan-Cun Street, Beijing 100081, China; Shenzhen Institute for Innovative Breeding, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.
authors.forename: Zhi-Kang
authors.initials: ZK
authors.lastname: Li
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D053263:Gene Regulatory Networks; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics* / Q000254:growth & development*; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*; D019655:Quantitative Trait, Heritable
chemical_list: D010940:Plant Proteins