Structure, expression, and functional analysis of the hexokinase gene family in rice (Oryza sativa L.)

Cho, Jung‐Il; Ryoo, Nayeon; Ko, Seho; Lee, Sang‐Kyu; Lee, Junok; Jung, Kyungsook; Lee, Youn‐Hyung; Bhoo, Seong Hee; Winderickx, Joris; An, Gynheung; Hahn, Tae‐Ryong; Jeon, Jong‐Seong

doi:10.1007/s00425-006-0251-y

Cited by 133 publications

(155 citation statements)

References 72 publications

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“…Hexokinase activity, which is crucial for channeling Glc into glycolysis, is enhanced under anoxia in rice (Guglielminetti et al, 1995a) and our microarray data reveal that OsHXK7 (Os05g09500) encodes for the previously measured anoxic hexokinase activity (Guglielminetti et al, 1995a). The transcripts coding for the other nine rice hexokinase genes (Cho et al, 2006) are expressed at low levels in the anoxic coleoptiles (see Supplemental Tables S1 and S2). Remarkably, OsHXK7 is a starvation-induced gene (Cho et al, 2006) and its induction under anoxia is likely a consequence of the lower sugar content of anoxic coleoptiles (Alpi and Beevers, 1983).…”

Section: Anaerobic Responses In Ricementioning

confidence: 58%

Transcript Profiling of the Anoxic Rice Coleoptile

Lasanthi-Kudahettige

Magneschi²,

Loreti³

et al. 2007

Plant Physiology

295

359

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Rice (Oryza sativa) seeds can germinate in the complete absence of oxygen. Under anoxia, the rice coleoptile elongates, reaching a length greater than that of the aerobic one. In this article, we compared and investigated the transcriptome of rice coleoptiles grown under aerobic and anaerobic conditions. The results allow drawing a detailed picture of the modulation of the transcripts involved in anaerobic carbohydrate metabolism, suggesting up-regulation of the steps required to produce and metabolize pyruvate and its derivatives. Sugars appear to play a signaling role under anoxia, with several genes indirectly up-regulated by anoxia-driven sugar starvation. Analysis of the effects of anoxia on the expansin gene families revealed that EXPA7 and EXPB12 are likely to be involved in rice coleoptile elongation under anoxia. Genes coding for ethylene response factors and heat shock proteins are among the genes modulated by anoxia in both rice and Arabidopsis (Arabidopsis thaliana). Identification of anoxiainduced ethylene response factors is suggestive because genes belonging to this gene family play a crucial role in rice tolerance to submergence, a process closely related to, but independent from, the ability to germinate under anoxia. Genes coding for some enzymes requiring oxygen for their activity are dramatically down-regulated under anoxia, suggesting the existence of an energysaving strategy in the regulation of gene expression.Higher plants are aerobic organisms that rapidly die when oxygen availability is limited due to soil flooding (Voesenek et al., 2006). Species originating from semiaquatic environments are, however, able to cope with flooding stress. They can survive complete submergence for weeks and some even have the capacity to grow vigorously and produce flowers and seeds in permanently water-saturated soils. In this context, a wellknown crop is rice (Oryza sativa), which produces high yields even when it is grown in water-logged rice paddies. A broad range of metabolic and morphological adaptations characterizes these tolerant species. Floodtolerant plants have developed the capacity to generate ATP without the presence of oxygen (fermentative metabolism) and/or to develop specific morphologies (e.g. air channels, enhanced shoot elongation) that improve the entrance of oxygen

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Section: Anaerobic Responses In Ricementioning

confidence: 58%

Transcript Profiling of the Anoxic Rice Coleoptile

Lasanthi-Kudahettige

Magneschi²,

Loreti³

et al. 2007

Plant Physiology

295

359

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“…OsHXK6 belongs to a hexokinase family comprising 10 members in rice (46). Among these members, OsHXK6 was closely related to AtHXK1, which functions in a complex involved in regulating gene expression or RNA metabolism in the nucleus (47).…”

Section: Discussionmentioning

confidence: 99%

Pentatricopeptide-repeat family protein RF6 functions with hexokinase 6 to rescue rice cytoplasmic male sterility

Huang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

131

122

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Cytoplasmic male sterility (CMS) has been extensively used for hybrid seed production in many major crops. Honglian CMS (HL-CMS) is one of the three major types of CMS in rice and has contributed greatly to food security worldwide. The HL-CMS trait is associated with an aberrant chimeric mitochondrial transcript, atp6-orfH79, which causes pollen sterility and can be rescued by two nonallelic restorer-offertility (Rf) genes, Rf5 or Rf6. Here, we report the identification of Rf6, which encodes a novel pentatricopeptide repeat (PPR) family protein with a characteristic duplication of PPR motifs 3-5. RF6 is targeted to mitochondria, where it physically associates with hexokinase 6 (OsHXK6) and promotes the processing of the aberrant CMSassociated transcript atp6-orfH79 at nucleotide 1238, which ensures normal pollen development and restores fertility. The duplicated motif 3 of RF6 is essential for RF6-OsHXK6 interactions, processing of the aberrant transcript, and restoration of fertility. Furthermore, reductions in the level of OsHXK6 result in atp6-orfH79 transcript accumulation and male sterility. Together these results reveal a novel mechanism for CMS restoration by which RF6 functions with OsHXK6 to restore HL-CMS fertility. The present study also provides insight into the function of hexokinase 6 in regulating mitochondrial RNA metabolism and may facilitate further exploitation of heterosis in rice.cytoplasmic male sterility | pentatricopeptide repeat | restorer-of-fertility | RF6 | hexokinase 6 P lant cytoplasmic male sterility (CMS) is a trait characterized by a lack of functional pollen grains in plants, although female gametes are still viable (1). CMS has been widely used to produce hybrid seeds to improve plant yield, improve resistance to diseases or stresses, or enhance taste (2). Plant CMS results from genomic incompatibility between mitochondria and nuclei and is typically associated with an aberrant chimeric gene in the mitochondria (3-6). A specific set of nuclear genes called restorer-of-fertility (Rf) genes, which primarily belong to the pentatricopeptide repeat (PPR) family, repress CMS through the promotion of the cleavage, degradation, or editing of CMS-associated aberrant transcripts or the inhibition of the translation of these genes (7-9). PPR proteins regulate RNA metabolism at multiple levels, from RNA editing, stability, processing, and splicing to translation (10, 11). PPR proteins can be classified into PLS and P families based on the structure of PPR motifs (11). PLS family members generally exhibit direct RNA binding (12)(13)(14) or editing activity (15-17), whereas P-family proteins often lack sites for binding to RNA, particularly mitochondrial CMS-related RNA (18,19). Most of the known PPR proteins implicated in restoration of fertility (RF) are P-family members. Thus, RF-related PPR proteins may require additional partners, such as RNA-binding or splicing factors to process CMSrelated transcripts.Rice CMS is categorized into three major types: Wild Abortive (WA), originating from...

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“…To prevent genomic DNA contaminations, primers were designed to amplify a region encompassing at least one intron for each gene (Supplementary Table 2). The rice actin1 gene OsAct1 was used as a PCR control (Cho et al, 2006). These experiments were repeated at least three times.…”

Section: Semi-quantitative Rt-pcr Analysismentioning

confidence: 99%

Identification and Characterization of the Duplicate Rice Sucrose Synthase Genes OsSUS5 and OsSUS7 Which Are Associated with the Plasma Membrane

Cho

Kim

et al. 2011

Molecules and Cells

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Systematic searches using the complete genome sequence of rice (Oryza sativa) identified OsSUS7, a new member of the rice sucrose synthase (OsSUS) gene family, which shows only nine single nucleotide substitutions in the OsSUS5 coding sequence. Comparative genomic analysis revealed that the synteny between OsSUS5 and OsSUS7 is conserved, and that significant numbers of transposable elements are scattered at both loci. In particular, a 17.6-kb genomic region containing transposable elements was identified in the 5′ upstream sequence of the OsSUS7 gene. GFP fusion experiments indicated that Os-SUS5 and OsSUS7 are largely associated with the plasma membrane and partly with the cytosol in maize mesophyll protoplasts. RT-PCR analysis and transient expression assays revealed that OsSUS5 and OsSUS7 exhibit similar expression patterns in rice tissues, with the highest expression evident in roots. These results suggest that two redundant genes, OsSUS5 and OsSUS7, evolved via duplication of a chromosome region and through the transposition of transposable elements.

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Structure, expression, and functional analysis of the hexokinase gene family in rice (Oryza sativa L.)

Cited by 133 publications

References 72 publications

Transcript Profiling of the Anoxic Rice Coleoptile

Transcript Profiling of the Anoxic Rice Coleoptile

Pentatricopeptide-repeat family protein RF6 functions with hexokinase 6 to rescue rice cytoplasmic male sterility

Identification and Characterization of the Duplicate Rice Sucrose Synthase Genes OsSUS5 and OsSUS7 Which Are Associated with the Plasma Membrane

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