Publications (6)30.88 Total impact
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Article: A GH3 family member, OsGH3-2, modulates auxin and abscisic acid levels and differentially affects drought and cold tolerance in rice.
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ABSTRACT: Plant responses to abiotic stresses are coordinated by arrays of growth and developmental processes. Indole-3-acetic acid (IAA) and abscisic acid (ABA) play critical roles in developmental programmes and environmental responses, respectively, through complex signalling and metabolism networks. However, crosstalk between the two phytohormones in the stress responses remains largely unknown. Here, it is reported that a GH3 family gene, OsGH3-2, encoding an enzyme catalysing IAA conjugation to amino acids, is involved in the modulation of ABA level and stress tolerance. Expression of OsGH3-2 was induced by drought but was suppressed by cold. Overexpression of OsGH3-2 in rice caused significant morphological aberrations related to IAA deficiency, such as dwarfism, smaller leaves, and fewer crown roots and root hairs. The overexpressing line showed significantly reduced carotene, ABA, and free IAA levels, greater stomata aperture, and faster water loss, and was hypersensitive to drought stress. However, the overexpressing line showed increased cold tolerance, which was due to the combined effects of reduced free IAA content, alleviated oxidative damage, and decreased membrane penetrability. Furthermore, expression levels of some ABA synthesis- and stress-related genes were significantly changed in the overexpression line. It was conclude that OsGH3-2 modulates both endogenous free IAA and ABA homeostasis and differentially affects drought and cold tolerance in rice.Journal of Experimental Botany 10/2012; · 5.36 Impact Factor -
Article: Characterization of an inositol 1,3,4-trisphosphate 5/6-kinase gene that is essential for drought and salt stress responses in rice.
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ABSTRACT: Drought and salt stresses are major limiting factors for crop production. To identify critical genes for stress resistance in rice (Oryza sativa L.), we screened T-DNA mutants and identified a drought- and salt-hypersensitive mutant dsm3. The mutant phenotype was caused by a T-DNA insertion in a gene encoding a putative inositol 1,3,4-trisphosphate 5/6-kinase previously named OsITPK2 with unknown function. Under drought stress conditions, the mutant had significantly less accumulation of osmolytes such as proline and soluble sugar and showed significantly reduced root volume, spikelet fertility, biomass, and grain yield; however, malondialdehyde level was increased in the mutant. Interestingly, overexpression of DSM3 (OsITPK2) in rice resulted in drought- and salt-hypersensitive phenotypes and physiological changes similar to those in the mutant. Inositol trisphosphate (IP3) level was decreased in the overexpressors under normal condition and drought stress. A few genes related to osmotic adjustment and reactive oxygen species scavenging were down-regulated in the mutant and overexpression lines. The expression level of DSM3 promoter-driven β-glucuronidase (GUS) reporter gene in rice was induced by drought, salt and abscisic acid. Protoplast transient expression assay indicated that DSM3 is an endoplasmic reticulum protein. Sequence analysis revealed six putative ITPKs in rice. Transcript level analysis of OsITPK genes revealed that they had different tempo-spatial expression patterns, and the responses of DSM3 to abiotic stresses, including drought, salinity, cold, and high temperature, were distinct from the other five members in rice. These results together suggest that DSM3/OsITPK2 is an important member of the OsITPK family for stress responses, and an optimal expression level is essential for drought and salt tolerance in rice.Plant Molecular Biology 12/2011; 77(6):547-63. · 4.15 Impact Factor -
Article: Characterization of the beta-carotene hydroxylase gene DSM2 conferring drought and oxidative stress resistance by increasing xanthophylls and abscisic acid synthesis in rice.
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ABSTRACT: Drought is a major limiting factor for crop production. To identify critical genes for drought resistance in rice (Oryza sativa), we screened T-DNA mutants and identified a drought-hypersensitive mutant, dsm2. The mutant phenotype was caused by a T-DNA insertion in a gene encoding a putative β-carotene hydroxylase (BCH). BCH is predicted for the biosynthesis of zeaxanthin, a carotenoid precursor of abscisic acid (ABA). The amounts of zeaxanthin and ABA were significantly reduced in two allelic dsm2 mutants after drought stress compared with the wild type. Under drought stress conditions, the mutant leaves lost water faster than the wild type and the photosynthesis rate, biomass, and grain yield were significantly reduced, whereas malondialdehyde level and stomata aperture were increased in the mutant. The mutant is also hypersensitive to oxidative stresses. The mutant had significantly lower maximal efficiency of photosystem II photochemistry and nonphotochemical quenching capacity than the wild type, indicating photoinhibition in photosystem II and decreased capacity for eliminating excess energy by thermal dissipation. Overexpression of DSM2 in rice resulted in significantly increased resistance to drought and oxidative stresses and increases of the xanthophylls and nonphotochemical quenching. Some stress-related ABA-responsive genes were up-regulated in the overexpression line. DSM2 is a chloroplast protein, and the response of DSM2 to environmental stimuli is distinctive from the other two BCH members in rice. We conclude that the DSM2 gene significantly contributes to control of the xanthophyll cycle and ABA synthesis, both of which play critical roles in the establishment of drought resistance in rice.Plant physiology 11/2010; 154(3):1304-18. · 6.53 Impact Factor -
Article: Identification and expression profiling analysis of TIFY family genes involved in stress and phytohormone responses in rice.
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ABSTRACT: The TIFY family is a novel plant-specific gene family involved in the regulation of diverse plant-specific biologic processes, such as development and responses to phytohormones, in Arabidopsis. However, there is limited information about this family in monocot species. This report identifies 20 TIFY genes in rice, the model monocot species. Sequence analysis indicated that rice TIFY proteins have conserved motifs beyond the TIFY domain as was previously shown in Arabidopsis. On the basis of their protein structures, members of the TIFY family can be divided into two groups. Transcript level analysis of OsTIFY genes in tissues and organs revealed different tempo-spatial expression patterns, suggesting that expression and function vary by stage of plant growth and development. Most of the OsTIFY genes were predominantly expressed in leaf. Nine OsTIFY genes were responsive to jasmonic acid and wounding treatments. Interestingly, almost all the OsTIFY genes were responsive to one or more abiotic stresses including drought, salinity, and low temperature. Over-expression of OsTIFY11a, one of the stress-inducible genes, resulted in significantly increased tolerance to salt and dehydration stresses. These results suggest that the OsTIFY family may have important roles in response to abiotic stresses. The data presented in this report provide important clues for further elucidating the functions of the genes in the OsTIFY family.Plant Molecular Biology 08/2009; 71(3):291-305. · 4.15 Impact Factor -
Article: Characterization of Glossy1-homologous genes in rice involved in leaf wax accumulation and drought resistance.
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ABSTRACT: The outermost surfaces of plants are covered with an epicuticular wax layer that provides a primary waterproof barrier and protection against different environmental stresses. Glossy 1 (GL1) is one of the reported genes controlling wax synthesis. This study analyzed GL1-homologous genes in Oryza sativa and characterized the key members of this family involved in wax synthesis and stress resistance. Sequence analysis revealed 11 homologous genes of GL1 in rice, designated OsGL1-1 to OsGL1-11. OsGL1-1, -2 and -3 are closely related to GL1. OsGL1-4, -5, -6, and -7 are closely related to Arabidopsis CER1 that is involved in cuticular wax biosynthesis. OsGL1-8, -9, -10 and -11 are closely related to SUR2 encoding a putative sterol desaturase also involved in epicuticular wax biosynthesis. These genes showed variable expression levels in different tissues and organs of rice, and most of them were induced by abiotic stresses. Compared to the wild type, the OsGL1-2-over-expression rice exhibited more wax crystallization and a thicker epicuticular layer; while the mutant of this gene showed less wax crystallization and a thinner cuticular layer. Chlorophyll leaching experiment suggested that the cuticular permeability was decreased and increased in the over-expression lines and the mutant, respectively. Quantification analysis of wax composition by GC-MS revealed a significant reduction of total cuticular wax in the mutant and increase of total cuticular wax in the over-expression plants. Compared to the over-expression and wild type plants, the osgl1-2 mutant was more sensitive to drought stress at reproductive stage, suggesting an important role of this gene in drought resistance.Plant Molecular Biology 04/2009; 70(4):443-56. · 4.15 Impact Factor -
Article: Characterization of OsbZIP23 as a key player of the basic leucine zipper transcription factor family for conferring abscisic acid sensitivity and salinity and drought tolerance in rice.
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ABSTRACT: OsbZIP23 is a member of the basic leucine zipper (bZIP) transcription factor family in rice (Oryza sativa). Expression of OsbZIP23 is strongly induced by a wide spectrum of stresses, including drought, salt, abscisic acid (ABA), and polyethylene glycol treatments, while other stress-responsive genes of this family are slightly induced only by one or two of the stresses. Transactivation assay in yeast demonstrated that OsbZIP23 functions as a transcriptional activator, and the sequences at the N terminus (amino acids 1-59) and a region close to the C terminus (amino acids 210-240) are required for the transactivation activity. Transient expression of OsbZIP23-green fluorescent protein in onion (Allium cepa) cells revealed a nuclear localization of the protein. Transgenic rice overexpressing OsbZIP23 showed significantly improved tolerance to drought and high-salinity stresses and sensitivity to ABA. On the other hand, a null mutant of this gene showed significantly decreased sensitivity to a high concentration of ABA and decreased tolerance to high-salinity and drought stress, and this phenotype can be complemented by transforming the OsbZIP23 back into the mutant. GeneChip and real-time polymerase chain reaction analyses revealed that hundreds of genes were up- or down-regulated in the rice plants overexpressing OsbZIP23. More than half of these genes have been annotated or evidenced for their diverse functions in stress response or tolerance. In addition, more than 30 genes that are possible OsbZIP23-specific target genes were identified based on the comparison of the expression profiles in the overexpressor and the mutant of OsbZIP23. Collectively, these results indicate that OsbZIP23 functions as a transcriptional regulator that can regulate the expression of a wide spectrum of stress-related genes in response to abiotic stresses through an ABA-dependent regulation pathway. We propose that OsbZIP23 is a major player of the bZIP family in rice for conferring ABA-dependent drought and salinity tolerance and has high potential usefulness in genetic improvement of stress tolerance.Plant physiology 11/2008; 148(4):1938-52. · 6.53 Impact Factor
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Institutions
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2008–2012
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Huazhong Agricultural University
- National Key Laboratory of Crop Genetic Improvement
Wuhan, Hubei, China
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