title: Characterization of Rubisco activase genes in maize: an α-isoform gene functions alongside a β-isoform gene.
abstract: Rubisco activase (RCA) catalyzes the activation of Rubisco in vivo and plays a crucial role in regulating plant growth. In maize (Zea mays), only β-form RCA genes have been cloned and characterized. In this study, a genome-wide survey revealed the presence of an α-form RCA gene and a β-form RCA gene in the maize genome, herein referred to as ZmRCAα and ZmRCAβ, respectively. An analysis of genomic DNA and complementary DNA sequences suggested that alternative splicing of the ZmRCAβ precursor mRNA (premRNA) at its 3' untranslated region could produce two distinctive ZmRCAβ transcripts. Analyses by electrophoresis and matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry showed that ZmRCAα and ZmRCAβ encode larger and smaller polypeptides of approximately 46 and 43 kD, respectively. Transcriptional analyses demonstrated that the expression levels of both ZmRCAα and ZmRCAβ were higher in leaves and during grain filling and that expression followed a specific cyclic day/night pattern. In 123 maize inbred lines with extensive genetic diversity, the transcript abundance and protein expression levels of these two RCA genes were positively correlated with grain yield. Additionally, both genes demonstrated a similar correlation with grain yield compared with three C₄ photosynthesis genes. Our data suggest that, in addition to the β-form RCA-encoding gene, the α-form RCA-encoding gene also contributes to the synthesis of RCA in maize and support the hypothesis that RCA genes may play an important role in determining maize productivity.
authors: Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China.
authors: Zhitong
authors: Z
authors: Yin
authors: Zhenliang
authors: Z
authors: Zhang
authors: Dexiang
authors: D
authors: Deng
authors: Maoni
authors: M
authors: Chao
authors: Qingsong
authors: Q
authors: Gao
authors: Yijun
authors: Y
authors: Wang
authors: Zefeng
authors: Z
authors: Yang
authors: Yunlong
authors: Y
authors: Bian
authors: Derong
authors: D
authors: Hao
authors: Chenwu
authors: C
authors: Xu
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D016415:Sequence Alignment; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D010455:Peptides; D010940:Plant Proteins; D012333:RNA, Messenger; C054765:rca protein, plant