title: Gene mapping and functional analysis of the novel leaf color gene SiYGL1 in foxtail millet [Setaria italica (L.) P. Beauv].
abstract: Setaria italica and its wild ancestor Setaria viridis are emerging as model systems for genetics and functional genomics research. However, few systematic gene mapping or functional analyses have been reported in these promising C4 models. We herein isolated the yellow-green leaf mutant (siygl1) in S. italica using forward genetics approaches. Map-based cloning revealed that SiYGL1, which is a recessive nuclear gene encoding a magnesium-chelatase D subunit (CHLD), is responsible for the mutant phenotype. A single Phe to Leu amino acid change occurring near the ATPase-conserved domain resulted in decreased chlorophyll (Chl) accumulation and modified chloroplast ultrastructure. However, the mutation enhanced the light-use efficiency of the siygl1 mutant, suggesting that the mutated CHLD protein does not completely lose its original activity, but instead, gains novel features. A transcriptional analysis of Chl a oxygenase revealed that there is a strong negative feedback control of Chl b biosynthesis in S. italica. The SiYGL1 mRNA was expressed in all examined tissues, with higher expression observed in the leaves. Comparison of gene expression profiles in wild-type and siygl1 mutant plants indicated that SiYGL1 regulates a subset of genes involved in photosynthesis (rbcL and LHCB1), thylakoid development (DEG2) and chloroplast signaling (SRP54CP). These results provide information regarding the mutant phenotype at the transcriptional level. This study demonstrated that the genetic material of a Setaria species could be ideal for gene discovery investigations using forward genetics approaches and may help to explain the molecular mechanisms associated with leaf color variation.
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.|College of Agronomy, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Sha
authors.identifier: http://orcid.org/0000-0002-5825-9598
authors.initials: S
authors.lastname: Tang
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.|College of Agronomy, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Shan
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Chanjuan
authors.initials: C
authors.lastname: Tang
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Qiannan
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Guanqing
authors.initials: G
authors.lastname: Jia
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.|College of Agronomy, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.
authors.forename: Yuanhuai
authors.initials: Y
authors.lastname: Han
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhi
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Xianmin
authors.initials: X
authors.lastname: Diao
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D002874:Chromosome Mapping; D003116:Color; D005838:Genotype; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D032983:Setaria Plant / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects
chemical_list: D002734:Chlorophyll