June 2013, Volume 55 Issue 6, Pages 489ĘC566.


Cover Caption: Yellow- and Black-seeded Brassica napus
About the cover: Yellow-seeded Brassica napus has advantages over the black-seeded variety, with reduced anti-nutritional polyphenilics and proanthocyanidins. In this issue, Jiang et al. (pp.537ĘC551) compare flavonoid biosynthesis in developing seeds of natural black-seeded rapeseed and yellow-seeded introgression lines derived from a somatic hybridization between B. napus and Sinapis alba, and show that most compounds and genes related to flavonoid biosynthesis are down-regulated in yellow-seeded lines.

 

          Metabolism and Biochemistry
Cloning, Characterization and Functional Analysis of Two Type 1 diacylglycerol acyltransferases (DGAT1s) from Tetraena mongolica
Author: Minchun Li, Mingming Zhao, Hanying Wu, Wang Wu and Yinong Xu
Journal of Integrative Plant Biology 2013 55(6): 490-503
Published Online: May 15, 2013
DOI: 10.1111/jipb.12046
      
    

Two cDNAs encoding putative type 1 acyl-CoA: diacylglycerol acyltransferases (DGAT1, EC 2.3.1.20), were cloned from Tetraena mongolica, an extreme xerophyte with high oil content in the stems. The 1 488-bp and 1 485-bp of the open reading frame (ORF) of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol (TAG) accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant (DGA1, LRO1, ARE1, ARE2) by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content (ranging from 37% to 108%), accompanied by altered fatty acid profiles.

Li M, Zhao M, Wu H, Wu W, Xu Y (2013) Cloning, characterization and functional analysis of two type 1 diacylglycerol acyltransferases (DGAT1s) from Tetraena mongolica. J. Integr. Plant Biol. 55(6), 490–503.

Abstract (Browse 1166)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Plant-environmental Interactions
Characterization and Mapping of a Salt-Sensitive Mutant in Rice (Oryza sativa L.)
Author: Jingwei Zhou, Fuzheng Wang, Ping Deng, Wen Jing and Wenhua Zhang
Journal of Integrative Plant Biology 2013 55(6): 504-513
Published Online: May 15, 2013
DOI: 10.1111/jipb.12048
      
    

A salt-sensitive mutant designated rice salt sensitive 2 (rss2) was isolated from the M2 generation of the rice cultivar Nipponbare mutagenized with ethyl methanesulfonate (EMS). This mutant exhibited a greater decrease in salt tolerance with a significant increase in Na+ content in its shoots. Genetic analysis indicated that the increase in Na+ in rss2 was controlled by a single recessive gene. Further genome-wide analysis of the linkage map constructed from the F2 population of rss2/Zhaiyeqing 8 (ZYQ8) showed that two quantitative trait loci (QTLs) on chromosomes 1 and 6 were responsible for the Na+ concentration in shoots, which explained 14.5% and 53.3%, respectively, of the phenotypic variance. The locus on chromosome 1, but not that on chromosome 6, was also detected in the F2 population of Nipponbare/ZYQ8, suggesting that the QTL on chromosome 6 was responsible for the salt sensitivity in rss2. By analyzing the recombination events in 220 mutant individuals of an enlarged mapping population of rss2/ZYQ8, the rss2 locus was precisely mapped to an interval of 605.3 kb between insertion/deletion (InDel) markers IM21962 and IM22567. This finding will facilitate the cloning of the rss2 locus and provide insight into the physiological mechanisms of salt sensitivity in rice.

Zhou J, Wang F, Deng P, Jing W, Zhang W (2013) Characterization and mapping of a salt-sensitive mutant in rice (Oryza sativa L.). J. Integr. Plant Biol. 55(6), 504–513.

Abstract (Browse 1546)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Silencing Brassinosteroid Receptor BRI1 Impairs Herbivory-elicited Accumulation of Jasmonic Acid-isoleucine and Diterpene Glycosides, but not Jasmonic Acid and Trypsin Proteinase Inhibitors in Nicotiana attenuata  
Author: Da-Hai Yang, Ian T. Baldwin and Jianqiang Wu
Journal of Integrative Plant Biology 2013 55(6): 514-526
Published Online: April 11, 2013
DOI: 10.1111/jipb.12035
      
    

The brassinosteroid (BR) receptor, BR insensitive 1 (BRI1), plays a critical role in plant development, but whether BRI1-mediated BR signaling is involved in plant defense responses to herbivores was largely unknown. Here, we examined the function of BRI1 in the resistance of Nicotiana attenuata (Solanaceae) to its specialist insect herbivore Manduca sexta. Jasmonic acid (JA) and JA-isoleucine conjugate (JA-Ile) are important hormones that mediate resistance to herbivores and we found that after wounding or simulated herbivory NaBRI1 had little effect on JA levels, but was important for the induction of JA-Ile. Further experiments revealed that decreased JAR (the enzyme for JA-Ile production) activity and availability of Ile in NaBRI1-silenced plants were likely responsible for the low JA-Ile levels. Consistently, M. sexta larvae gained more weight on NaBRI1-silenced plants than on the control plants. Quantification of insect feeding-induced secondary metabolites revealed that silencing NaBRI1 resulted in decreased levels of carbon-rich defensive secondary metabolites (hydroxygeranyllinalool diterpene glycosides, chlorogenic acid, and rutin), but had little effect on the nitrogen-rich ones (nicotine and trypsin proteinase inhibitors). Thus, NaBRI1-mediated BR signaling is likely involved in plant defense responses to M. sexta, including maintaining JA-Ile levels and the accumulation of several carbon-rich defensive secondary metabolites.

Yang DH, Baldwin IT, Wu J (2013) Silencing brassinosteroid receptor BRI1 impairs herbivory-elicited accumulation of jasmonic acid-isoleucine and diterpene glycosides, but not jasmonic acid and trypsin proteinase inhibitors in Nicotiana attenuata. J. Integr. Plant Biol. 55(6), 514–526.

Abstract (Browse 1508)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Nitric Oxide Blocks Blue Light-Induced K+ Influx by Elevating the Cytosolic Ca2+ Concentration in Vicia faba L. Guard Cells
Author: Xiang Zhao, Yuan-Yuan Li, Hui-Li Xiao, Chang-Shui Xu and Xiao Zhang
Journal of Integrative Plant Biology 2013 55(6): 527-536
Published Online: April 12, 2013
DOI: 10.1111/jipb.12038
      
    

Ca2+ plays a pivotal role in nitric oxide (NO)-promoted stomatal closure. However, the function of Ca2+ in NO inhibition of blue light (BL)-induced stomatal opening remains largely unknown. Here, we analyzed the role of Ca2+ in the crosstalk between BL and NO signaling in Vicia faba L. guard cells. Extracellular Ca2+ modulated the BL-induced stomatal opening in a dose-dependent manner, and an application of 5 μM Ca2+ in the pipette solution significantly inhibited BL-activated K+ influx. Sodium nitroprusside (SNP), a NO donor, showed little effect on BL-induced K+ influx and stomatal opening response in the absence of extracellular Ca2+, but K+ influx and stomatal opening were inhibited by SNP when Ca2+ was added to the bath solution. Interestingly, although both SNP and BL could activate the plasma membrane Ca2+ channels and induce the rise of cytosolic Ca2+, the change in levels of Ca2+ channel activity and cytosolic Ca2+ concentration were different between SNP and BL treatments. SNP at 100 μM obviously activated the plasma membrane Ca2+ channels and induced cytosolic Ca2+ rise by 102.4%. In contrast, a BL pulse (100 μmol/m2 per s for 30 s) slightly activated the Ca2+ channels and resulted in a Ca2+ rise of only 20.8%. Consistently, cytosolic Ca2+ promoted K+ influx at 0.5 μM or below, and significantly inhibited K+ influx at 5 μM or above. Taken together, our findings indicate that Ca2+ plays dual and distinctive roles in the crosstalk between BL and NO signaling in guard cells, mediating both the BL-induced K+ influx as an activator at a lower concentration and the NO-blocked K+ influx as an inhibitor at a higher concentration.

Zhao X, Li YY, Xiao HL, Xu CS, Zhang X (2013) Nitric oxide blocks blue light-induced K+ influx by elevating the cytosolic Ca2+ concentration in Vicia faba L. guard cells. J. Integr. Plant Biol. 55(6), 527–536.

Abstract (Browse 1452)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Molecular Physiology
Phenolic Composition Analysis and Gene Expression in Developing Seeds of Yellow- and Black- seeded Brassica napus
Author: Jinjin Jiang, Yanlin Shao, Aimin Li, Chunliang Lu, Yongtai Zhang and Youping Wang
Journal of Integrative Plant Biology 2013 55(6): 537-551
Published Online: June 12, 2013
DOI: 10.1111/jipb.12039
      
    

Breeders have focused on yellow-seeded Brassica napus (rapeseed) for its better quality compared with the black-seeded variety. Moreover, flavonoids have been associated with this kind of rapeseed. In this study, we applied lipid chromatography-electrospray ionization mass spectrometry (LC-ESI-MSn) to compare flavonoids in developing seeds of natural black-seeded B. napus and yellow-seeded introgression lines selected from progenies of B. napus–Sinapis alba somatic hybrids. Aside from the most abundant phenolic compounds (sinapine and sinapic acid) and 1, 2-disinapoylglucose, 16 different flavonoids were identified and quantified, including (-)-epicatechin, five monocharged oligomers of (-)-epicatechin ([DP 2], [DP 3], [DP 4] [DP 2]B2 and [DP 2]B5), quercetin, kaempferol, isorhamnetin-dihexoside, kaempferol-sinapoyl-trihexoside, isorhamnetin-sinapoyl-trihexoside, isorhamnetin-hexoside-sulfate, and isorhamnetin-3-O-glucoside. Most of the flavonoids accumulated with seed development, whereas some rapidly decreased during maturation. The content of these flavonoids were lower in the yellow-seeded materials than in the black seeds. In addition, variations of insoluble procyanidin oligomers and soluble phenolic acids were observed among both rapeseed varieties. Transcriptome changes of genes participating in the flavonoid pathway were discovered by quantitative reverse transcription polymerase chain reaction analysis. Consistent with flavonoid changes identified by high performance liquid chromatography analysis, the expression of most genes in the flavonoid biosynthetic pathway was also downregulated.

Jiang J, Shao Y, Li A, Lu C, Zhang Y, Wang Y (2013) Phenolic composition analysis and gene expression in developing seeds of yellow- and black-seeded Brassica napus. J. Integr. Plant Biol. 55(6), 537–551.

Abstract (Browse 1016)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Molecular Ecology and Evolution
Genome-wide Analysis of Plant-specific Dof Transcription Factor Family in Tomato  
Author: Xiaofeng Cai, Yuyang Zhang, Chanjuan Zhang, Tingyan Zhang, Tixu Hu, Jie Ye, Junhong Zhang, Taotao Wang, Hanxia Li and Zhibiao Ye
Journal of Integrative Plant Biology 2013 55(6): 552-566
Published Online: June 12, 2013
DOI: 10.1111/jipb.12043
      
    

The Dof (DNA binding with One Finger) family encoding single zinc finger proteins has been known as a family of plant-specific transcription factors. These transcription factors are involved in a variety of functions of importance for different biological processes in plants. In the current study, we identified 34 Dof family genes in tomato, distributed on 11 chromosomes. A complete overview of SlDof genes in tomato is presented, including the gene structures, chromosome locations, phylogeny, protein motifs and evolution pattern. Phylogenetic analysis of 34 SlDof proteins resulted in four classes constituting six clusters. In addition, a comparative analysis between these genes in tomato, Arabidopsis and rice was also performed. The tomato Dof family expansion has been dated to recent duplication events, and segmental duplication is predominant for the SlDof genes. Furthermore, the SlDof genes displayed differential expression either in their transcript abundance or in their expression patterns under normal growth conditions. This is the first step towards genome-wide analyses of the Dof genes in tomato. Our study provides a very useful reference for cloning and functional analysis of the members of this gene family in tomato and other species.

Cai X, Zhang Y, Zhang C, Zhang T, Hu T, Ye J, Zhang J, Wang T, Li H, Ye Z (2013) Genome-wide analysis of plant-specific dof transcription factor family in tomato. J. Integr. Plant Biol. 55(6), 552–566.

Abstract (Browse 1431)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
 

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