title: Physiological Characterization and Comparative Transcriptome Analysis of White and Green Leaves of Ananas comosus var. bracteatus.
abstract: Leaf coloration is one of the most important and attractive characteristics of Ananas comosus var. bracteatus. The chimeric character is not stable during the in vitro tissue culturing. Many regenerated plants lost economic values for the loss of the chimeric character of leaves. In order to reveal the molecular mechanisms involved in the albino phenotype of the leaf cells, the physiological and transcriptional differences between complete white (CWh) and green (CGr) leaf cells of A. comosus var. bracteatus were analyzed. A total of 1,431 differentially expressed unigenes (DEGs) in CGr and CWh leaves were identified using RNA-seq. A comparison to the COG, GO and KEGG annotations revealed DEGs involved in chlorophyll biosynthesis, chloroplast development and photosynthesis. Furthermore, the measurement of main precursors of chlorophyll in the CWh leaves confirmed that the rate-limiting step in chlorophyll biosynthesis, and thus the cause of the albino phenotype of the white cells, was the conversion of pyrrole porphobilinogen (PBG) to uroporphyrinogen III (Uro III). The enzyme activity of porphobilinogen deaminase (PBGD) and uroporporphyrinogn III synthase (UROS), which catalyze the transition of PBG to Uro III, was significantly decreased in the CWh leaves. Our data showed the transcriptional differences between the CWh and CGr plants and characterized key steps in chlorophyll biosynthesis of the CWh leaves. These results contribute to our understanding of the mechanisms and regulation of pigment biosynthesis in the CWh leaf cells of A. comosus var. bracteatus.
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Plant Protection, Agricultural Research Organization, The Volcani Center, Beit Dagan, Israel.
authors.forename: Surapathrudu
authors.initials: S
authors.lastname: Kanakala
authors.affiliation: Horticultural Biotechnology College of South China Agricultural University, Guangzhou, Guangdong, China.
authors.forename: Yehua
authors.initials: Y
authors.lastname: He
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Zhong
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Sanmiao
authors.initials: S
authors.lastname: Yu
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Ruixue
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Lingxia
authors.initials: L
authors.lastname: Sun
authors.affiliation: College of Landscape Architecture of Sichuan Agricultural University, Chengdu, Sichuan, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D031230:Ananas / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D059014:High-Throughput Nucleotide Sequencing; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D002734:Chlorophyll