title: Transcriptional analyses of natural leaf senescence in maize.
abstract: Leaf senescence is an important biological process that contributes to grain yield in crops. To study the molecular mechanisms underlying natural leaf senescence, we harvested three different developmental ear leaves of maize, mature leaves (ML), early senescent leaves (ESL), and later senescent leaves (LSL), and analyzed transcriptional changes using RNA-sequencing. Three sets of data, ESL vs. ML, LSL vs. ML, and LSL vs. ESL, were compared, respectively. In total, 4,552 genes were identified as differentially expressed. Functional classification placed these genes into 18 categories including protein metabolism, transporters, and signal transduction. At the early stage of leaf senescence, genes involved in aromatic amino acids (AAAs) biosynthetic process and transport, cellular polysaccharide biosynthetic process, and the cell wall macromolecule catabolic process, were up-regulated. Whereas, genes involved in amino acid metabolism, transport, apoptosis, and response to stimulus were up-regulated at the late stage of leaf senescence. Further analyses reveals that the transport-related genes at the early stage of leaf senescence potentially take part in enzyme and amino acid transport and the genes upregulated at the late stage are involved in sugar transport, indicating nutrient recycling mainly takes place at the late stage of leaf senescence. Comparison between the data of natural leaf senescence in this study and previously reported data for Arabidopsis implies that the mechanisms of leaf senescence in maize are basically similar to those in Arabidopsis. A comparison of natural and induced leaf senescence in maize was performed. Athough many basic biological processes involved in senescence occur in both types of leaf senescence, 78.07% of differentially expressed genes in natural leaf senescence were not identifiable in induced leaf senescence, suggesting that differences in gene regulatory network may exist between these two leaf senescence programs. Thus, this study provides important information for understanding the mechanism of leaf senescence in maize.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Wei Yang
authors.initials: WY
authors.lastname: Zhang
authors.affiliation: College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Yong Chao
authors.initials: YC
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Wen Lan
authors.initials: WL
authors.lastname: Li
authors.affiliation: College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
authors.affiliation: College of Information Sciences and Engineering, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Yue
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Xian Sheng
authors.initials: XS
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
authors.forename: Xiang Yu
authors.initials: XY
authors.lastname: Zhao
mesh_terms: D016922:Cellular Senescence / Q000235:genetics*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D017343:Genes, Plant; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
chemical_list: D012333:RNA, Messenger