title: Effects of drought on gene expression in maize reproductive and leaf meristem tissue revealed by RNA-Seq.
abstract: Drought stress affects cereals especially during the reproductive stage. The maize (Zea mays) drought transcriptome was studied using RNA-Seq analysis to compare drought-treated and well-watered fertilized ovary and basal leaf meristem tissue. More drought-responsive genes responded in the ovary compared with the leaf meristem. Gene Ontology enrichment analysis revealed a massive decrease in transcript abundance of cell division and cell cycle genes in the drought-stressed ovary only. Among Gene Ontology categories related to carbohydrate metabolism, changes in starch and Suc metabolism-related genes occurred in the ovary, consistent with a decrease in starch levels, and in Suc transporter function, with no comparable changes occurring in the leaf meristem. Abscisic acid (ABA)-related processes responded positively, but only in the ovaries. Related responses suggested the operation of low glucose sensing in drought-stressed ovaries. The data are discussed in the context of the susceptibility of maize kernel to drought stress leading to embryo abortion and the relative robustness of dividing vegetative tissue taken at the same time from the same plant subjected to the same conditions. Our working hypothesis involves signaling events associated with increased ABA levels, decreased glucose levels, disruption of ABA/sugar signaling, activation of programmed cell death/senescence through repression of a phospholipase C-mediated signaling pathway, and arrest of the cell cycle in the stressed ovary at 1 d after pollination. Increased invertase levels in the stressed leaf meristem, on the other hand, resulted in that tissue maintaining hexose levels at an "unstressed" level, and at lower ABA levels, which was correlated with successful resistance to drought stress.
authors: Virginia Bioinformatics Institute , Virginia Tech, Blacksburg, Virginia 24061, USA.
authors: Akshay
authors: A
authors: Kakumanu
authors: Madana M R
authors: MM
authors: Ambavaram
authors: Curtis
authors: C
authors: Klumas
authors: Arjun
authors: A
authors: Krishnan
authors: Utlwang
authors: U
authors: Batlang
authors: Elijah
authors: E
authors: Myers
authors: Ruth
authors: R
authors: Grene
authors: Andy
authors: A
authors: Pereira
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological; D059447:Cell Cycle Checkpoints; D016923:Cell Death; D002455:Cell Division; D055864:Droughts; D035264:Flowers / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005947:Glucose / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D022821:RNA Splice Sites; D018749:RNA, Plant / Q000235:genetics; D012639:Seeds / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D013312:Stress, Physiological; D059467:Transcriptome; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D022821:RNA Splice Sites; D018749:RNA, Plant; D000040:Abscisic Acid; D010738:Type C Phospholipases; D005947:Glucose