June 2015, Volume 57 Issue 6, Pages 518每601.


Cover Caption: Pollen Tubes Targeting Ovules
Small peptides play key roles for plant reproduction, especially in the male-female communication. In this issue, Huang et al. (pp. 518每521) show that cysteine-rich peptides represent a major class of genes expressed in the female gametophyte during ovule maturation, fertilization and early seed development in Arabidopsis. The cover shows pollens from proLAT52::GFP proHTR10:HTR10-RFP transgenic plants moving towards ovules in vitro. Red fluorescence in ovules is from auto-fluorescence.

 

          Letter to the Editor
Active role of small peptides in Arabidopsis reproduction: Expression evidence  
Author: Qingpei Huang, Thomas Dresselhaus, Hongya Gu and Li-Jia Qu
Journal of Integrative Plant Biology 2015 57(6): 518每521
Published Online: March 31, 2015
DOI: 10.1111/jipb.12356
Abstract (Browse 788)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Large number of small peptides exhibit gametophyte-specific and dynamic expression profiles along the ovule developmental axis, implicating their vital function in plant reproduction.
          Cell and Developmental Biology
Molecular cloning and functional analysis of the FLOWERING LOCUS T (FT) homolog GhFT1 from Gossypium hirsutum  
Author: Danli Guo, Chao Li, Rui Dong, Xiaobo Li, Xiangwen Xiao and Xianzhong Huang
Journal of Integrative Plant Biology 2015 57(6): 522每533
Published Online: November 27, 2014
DOI: 10.1111/jipb.12316
      
    

FLOWERING LOCUS T (FT) encodes a member of the phosphatidylethanolamine-binding protein (PEBP) family that functions as the mobile floral signal, playing an important role in regulating the floral transition in angiosperms. We isolated an FT-homolog (GhFT1) from Gossypium hirsutum L. cultivar, Xinluzao 33 GhFT1 was predominantly expressed in stamens and sepals, and had a relatively higher expression level during the initiation stage of fiber development. GhFT1 mRNA displayed diurnal oscillations in both long-day and short-day condition, suggesting that the expression of this gene may be under the control of the circadian clock. Subcellular analysis revealed that GhFT1 protein located in the cytoplasm and nucleus. Ectopic expression of GhFT1 in transgenic arabidopsis plants resulted in early flowering compared with wild-type plants. In addition, ectopic expression of GhFT1 in arabidopsis ft-10 mutants partially rescued the extremely late flowering phenotype. Finally, several flowering related genes functioning downstream of AtFT were highly upregulated in the 35S::GhFT1 transgenic arabidopsis plants. In summary, GhFT1 is an FT-homologous gene in cotton that regulates flower transition similar to its orthologs in other plant species and thus it may be a candidate target for promoting early maturation in cotton breeding.

 

Guo D, Li C, Dong R, Li X, Xiao X, Huang X (2015) Molecular cloning and functional analysis of the FLOWERING LOCUS T (FT) homolog GhFT1 from Gossypium hirsutum. J Integr Plant Biol 57:522–533 doi: 10.1111/jipb.12316

Abstract (Browse 1063)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
A florigen homologous gene GhFT1 in cotton was characterized, which shares the similar expression pattern with other FT genes but also is expressed in fiber. GhFT1 protein locates both in the cytoplasm and the nucleus. GhFT1 promotes flowering in transgenic arabidopsis and can be used to promote early maturation in cotton breeding.
          Molecular Physiology
Improved oxidative tolerance in suspension-cultured cells of C4-pepctransgenic rice by H2O2 and Ca2+ under PEG-6000
Author: Baoyun Qian, Xia Li, Xiaolong Liu and Man Wang
Journal of Integrative Plant Biology 2015 57(6): 534每549
Published Online: September 17, 2014
DOI: 10.1111/jipb.12283
      
    
To understand the molecular responses of PC (Overexpressing the maize C4-pepc gene, which encodes phosphoenolpyruvate carboxylase (PEPC)), to drought stress at cell level, we analyzed changes in the levels of signaling molecules (hydrogen peroxide (H2O2), calcium ion (Ca2+), and nitric oxide (NO)) in suspension-cultured PC and wild-type (WT) rice (Oryza sativa L.) cell under drought stress induced by 20% polyethylene glycol 6000 (PEG-6000). Results demonstrated that PC improved drought tolerance by enhancing antioxidant defense, retaining higher relative water content, survival percentages, and dry weight of cells. In addition, PEPC activity in PC under PEG treatment was strengthened by addition of H2O2 inhibitor, dimethylthiourea (DMTU) and NO synthesis inhibitor, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), respectively, while that in PC was weakened by addition of free calcium chelator, ethylene glycol-bis(b-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) + calcium channel outflow inhibitor, ruthenium red (RR) + plasma membrane channel blocker La(NO3)3, but EGTA + RR did not. Results also showed that NO and Ca2+ was lying downstream of H2O2 in drought-induced signaling. Calcium ion was also involved in the expression of C4-pepc in PC. These results suggested that PC could improve oxidative tolerance in suspension-cultured cells and the acquisition of this tolerance required downregulation of H2O2 and the entry of extracellular Ca2+ into cells across the plasma membrane for regulation of PEPC activity and C4-pepc expression.

 

Qian B, Li X, Liu X, Wang M (2015) Improved oxidative tolerance in suspension坼cultured cells of C4-pepctransgenic rice by H2O2 and Ca2+ under PEG坼6000. J Integr Plant Biol 57: 534–549. doi: 10.1111/jipb.12283

Abstract (Browse 944)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Research on transgenic rice lines expressing high levels of C4-pepc (hereafter, PC lines) showed that PC could improve oxidative tolerance via the down-regulation of H2O2 and the entry of extracellular Ca2+ into cells across the plasma membrane for regulation of PEPC activity and C4-pepc expression.
Nitric oxide alleviates aluminum-induced oxidative damage through regulating the ascorbate-glutathione cycle in roots of wheat
Author: Chengliang Sun, Lijuan Liu, Yan Yu, Wenjing Liu, Lingli Lu, Chongwei Jin and Xianyong Lin
Journal of Integrative Plant Biology 2015 57(6): 550每561
Published Online: October 16, 2014
DOI: 10.1111/jipb.12298
      
    

The possible association with nitric oxide (NO) and ascorbate-glutathione (AsA-GSH) cycle in regulating aluminum (Al) tolerance of wheat (Triticum aestivum L.) was investigated using two genotypes with different Al resistance. Exposure to Al inhibited root elongation, and triggered lipid peroxidation and oxidation of AsA to dehydroascorbate and GSH to glutathione disulfide in wheat roots. Exogenous NO significantly increased endogenous NO levels, and subsequently alleviated Al-induced inhibition of root elongation and oxidation of AsA and GSH to maintain the redox molecules in the reduced form in both wheat genotypes. Under Al stress, significantly increased activities and gene transcriptional levels of ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase, were observed in the root tips of the Al-tolerant genotype Jian-864. Nitric oxide application enhanced the activity and gene transcriptional level of these enzymes in both wheat genotypes. γ-Glutamylcysteine synthetase was not significantly affected by Al or NO, but NO treatments increased the activity of glutathione peroxidase and glutathione S-transferase to a greater extent than the Al-treated wheat seedlings. Proline was significantly decreased by Al, while it was not affected by NO. These results clearly suggest that NO protects wheat root against Al-induced oxidative stress, possibly through its regulation of the AsA-GSH cycle.

 

Sun C, Liu L, Yu Y, Liu W, Lu L, Jin C, Lin X (2015) Nitric oxide alleviates aluminum-induced oxidative damage through regulating the ascorbate-glutathione cycle in roots of wheat. J Integr Plant Biol 57: 550–561. doi: 10.1111/jipb.12298

Abstract (Browse 835)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Nitric oxide apparently alleviated Al-induced root growth inhibition, probably by preventing oxidative damage, directly scavenging ROS, elevating the activity of antioxidant enzymes in the AsA-GSH cycle, and maintaining high levels of AsA and GSH.
          Plant-environmental Interactions
Mutation of Oryza sativa CORONATINE INSENSITIVE 1b (OsCOI1b) delays leaf senescence  
Author: Sang-Hwa Lee, Yasuhito Sakuraba, Taeyoung Lee, Kyu-Won Kim, Gynheung An, Han Yong Lee and Nam-Chon Paek
Journal of Integrative Plant Biology 2015 57(6): 562每576
Published Online: August 22, 2014
DOI: 10.1111/jipb.12276
      
    

Jasmonic acid (JA) functions in plant development, including senescence and immunity. Arabidopsis thaliana CORONATINE INSENSITIVE 1 encodes a JA receptor and functions in the JA-responsive signaling pathway. The Arabidopsis genome harbors a single COI gene, but the rice (Oryza sativa) genome harbors three COI homologs, OsCOI1a, OsCOI1b, and OsCOI2. Thus, it remains unclear whether each OsCOI has distinct, additive, synergistic, or redundant functions in development. Here, we use the oscoi1b-1 knockout mutants to show that OsCOI1b mainly affects leaf senescence under senescence-promoting conditions. oscoi1b-1 mutants stayed green during dark-induced and natural senescence, with substantial retention of chlorophylls and photosynthetic capacity. Furthermore, several senescence-associated genes were downregulated in oscoi1b-1 mutants, including homologs of Arabidopsis thaliana ETHYLENE INSENSITIVE 3 and ORESARA 1, important regulators of leaf senescence. These results suggest that crosstalk between JA signaling and ethylene signaling affects leaf senescence. The Arabidopsis coi1-1 plants containing 35S:OsCOI1a or 35S:OsCOI1b rescued the delayed leaf senescence during dark incubation, suggesting that both OsCOI1a and OsCOI1b are required for promoting leaf senescence in rice. oscoi1b-1 mutants showed significant decreases in spikelet fertility and grain weight, leading to severe reduction of grain yield, indicating that OsCOI1-mediated JA signaling affects spikelet fertility and grain filling.

 

Lee SH, Sakuraba Y, Lee T, Kim KW, An G, Lee HY, Paek NC (2015) Mutation of Oryza sativa CORONATINE INSENSITIVE 1b (OsCOI1b) delays leaf senescence. J Integr Plant Biol 57: 562–576. doi: 10.1111/jipb.12276

Abstract (Browse 1114)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Mutant of OsCOI1b, a jasmonate receptor and one of the three COI homologs in rice, delays leaf senescence during both dark-induced and natural senescence, indicating that OsCOI1b is involved in the promotion of leaf senescence.
Infection of Ustilaginoidea virens intercepts rice seed formation but activates grain-filling-related genes  
Author: Jing Fan, Xiao-Yi Guo, Liang Li, Fu Huang, Wen-Xian Sun, Yan Li, Yan-Yan Huang, Yong-Ju Xu, Jun Shi, Yang Lei1, Ai-Ping Zheng and Wen-Ming Wang
Journal of Integrative Plant Biology 2015 57(6): 577每590
Published Online: October 16, 2014
DOI: 10.1111/jipb.12299
      
    

Rice false smut has become an increasingly serious disease in rice (Oryza sativa L.) production worldwide. The typical feature of this disease is that the fungal pathogen Ustilaginoidea virens (Uv) specifically infects rice flower and forms false smut ball, the ustiloxin-containing ball-like fungal colony, of which the size is usually several times larger than that of a mature rice seed. However, the underlying mechanisms of Uv-rice interaction are poorly understood. Here, we applied time-course microscopic and transcriptional approaches to investigate rice responses to Uv infection. The results demonstrated that the flower-opening process and expression of associated transcription factors, including ARF6 and ARF8, were inhibited in Uv-infected spikelets. The ovaries in infected spikelets were interrupted in fertilization and thus were unable to set seeds. However, a number of grain-filling-related genes, including seed storage protein genes, starch anabolism genes and endosperm-specific transcription factors (RISBZ1 and RPBF), were highly transcribed as if the ovaries were fertilized. In addition, critical defense-related genes like NPR1 and PR1 were downregulated by Uv infection. Our data imply that Uv may hijack host nutrient reservoir by activation of the grain-filling network because of growth and formation of false smut balls.

 

Fan J, Guo XY, Li L, Huang F, Sun WX, Li Y, Huang YY, Xu YJ, Shi J, Lei Y, Zheng AP, Wang WM (2015) Infection of Ustilaginoidea virens intercepts rice seed formation but activates grain-filling-related genes. J Integr Plant Biol 57: 577–590. doi: 10.1111/jipb.12299

Abstract (Browse 1277)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Rice false smut disease is featured by conversion of a rice grain into a ball-shaped fungal mass through that the pathogen intercepts flower fertilization and seed setting. Transcriptome analysis reveals the activation of grain-filling network upon pathogen infection, implying that false smut pathogen hijacks host nutrient reservoir for its colonization.
Selective silencing of 2Cys and type-IIB Peroxiredoxins discloses their roles in cell redox state and stress signaling
Author: Patrícia Vidigal, Ana Montserrat Martin-Hernandez, Cèlia Guiu-Aragonés, Sara Amâncio and Luísa Carvalho
Journal of Integrative Plant Biology 2015 57(6): 591每601
Published Online: October 16, 2014
DOI: 10.1111/jipb.12296
      
    

Peroxiredoxins (Prx) catalyse the reduction of hydrogen peroxide (H2O2) and, in association with catalases and other peroxidases, may participate in signal transduction by regulating intercellular H2O2 concentration that in turn can control gene transcription and cell signaling. Using virus-induced-gene-silencing (VIGS), 2-Cys Peroxiredoxin (2CysPrx) family and type-II Peroxiredoxin B (PrxIIB) gene were silenced in Nicotiana benthamiana, to study the impact that the loss of function of each Prx would have in the antioxidant system under control (22 °C) and severe heat stress conditions (48 °C). The results showed that both Prxs, although in different organelles, influence the regeneration of ascorbate to a significant extent, but with different purposes. 2CysPrx affects abscisic acid (ABA) biosynthesis through ascorbate, while PrxIIB does it probably through the xanthophyll cycle. Moreover, 2CysPrx is key in H2O2 scavenging and in consequence in the regulation of ABA signaling downstream of reactive oxygen species and PrxIIB provides an important assistance for H2O2 peroxisome scavenges.

 

Vidigal P, Martin-Hernandez AM, Guiu-Aragonés C, Amâncio S, Carvalho L (2015) Selective silencing of 2Cys and type-IIB Peroxiredoxins discloses their roles in cell redox state and stress signaling. J Integr Plant Biol 57: 591–601. doi: 10.1111/jipb.12296

Abstract (Browse 964)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Through the silencing of two different peroxiredoxin, it was possible to learn that 2Cys-Peroxiredoxin influences the biosynthesis of the stress hormone abscisic acid through the regeneration of ascorbate. Ascorbate regeneration is also affected by Peroxiredoxin-IIB through the xanthophyll cycle, another adaptive mechanism triggered in stressful conditions.
 

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