October 2014, Volume 56 Issue 10, Pages 962每1031.


Cover Caption: The Role of GAs in Nodulation
About the cover: Legume nodulationis coordinated by a number of signalling molecules, including phytohormones. In this issue, Hayashi et al. (pp. 971每978) critically investigate the role of gibberellins (GAs) in nodule development, and conclude that GAs positively-regulate nodulation, with too much or too little being inhibitory to the process.

 

          Minireview
Roles of small RNAs in plant disease resistance  
Author: Li Yang and Hai Huang
Journal of Integrative Plant Biology 2014 56(10): 962每970
Published Online: March 26, 2014
DOI: 10.1111/jipb.12200
      
    

The interaction between plants and pathogens represents a dynamic competition between a robust immune system and efficient infectious strategies. Plant innate immunity is composed of complex and highly regulated molecular networks, which can be triggered by the perception of either conserved or race-specific pathogenic molecular signatures. Small RNAs are emerging as versatile regulators of plant development, growth and response to biotic and abiotic stresses. They act in different tiers of plant immunity, including the pathogen-associated molecular pattern-triggered and the effector-triggered immunity. On the other hand, pathogens have evolved effector molecules to suppress or hijack the host small RNA pathways. This leads to an arms race between plants and pathogens at the level of small RNA-mediated defense. Here, we review recent advances in small RNA-mediated defense responses and discuss the challenging questions in this area.

 

Yang L, Huang H (2014) Roles of small RNAs in plant disease resistance. J Integr Plant Biol 56: 962–970. doi: 10.1111/jipb.12200

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Mechanistic action of gibberellins in legume nodulation
Author: Satomi Hayashi, Peter M. Gresshoff and Brett J. Ferguson
Journal of Integrative Plant Biology 2014 56(10): 971每978
Published Online: March 26, 2014
DOI: 10.1111/jipb.12201
      
    

Legume plants are capable of entering into a symbiotic relationship with rhizobia bacteria. This results in the formation of novel organs on their roots, called nodules, in which the bacteria capture atmospheric nitrogen and provide it as ammonium to the host plant. Complex molecular and physiological changes are involved in the formation and establishment of such nodules. Several phytohormones are known to play key roles in this process. Gibberellins (gibberellic acids; GAs), a class of phytohormones known to be involved in a wide range of biological processes (i.e., cell elongation, germination) are reported to be involved in the formation and maturation of legume nodules, highlighted by recent transcriptional analyses of early soybean symbiotic steps. Here, we summarize what is currently known about GAs in legume nodulation and propose a model of GA action during nodule development. Results from a wide range of studies, including GA application, mutant phenotyping, and gene expression studies, indicate that GAs are required at different stages, with an optimum, tightly regulated level being key to achieve successful nodulation. Gibberellic acids appear to be required at two distinct stages of nodulation: (i) early stages of rhizobia infection and nodule primordium establishment; and (ii) later stages of nodule maturation.

 

Hayashi S, Gresshoff PM, Ferguson BJ (2014) Mechanistic action of gibberellins in legume nodulation. J Integr Plant Biol 56: 971–978 doi: 10.1111/jipb.12201

Abstract (Browse 974)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Cell and Developmental Biology
Rice CYP703A3, a cytochrome P450 hydroxylase, is essential for development of anther cuticle and pollen exine
Author: Xijia Yang, Di Wu, Jianxin Shi, Yi He, Franck Pinot, Bernard Grausem, Changsong Yin, Lu Zhu, Mingjiao Chen, Zhijing Luo, Wanqi Liang and Dabing Zhang
Journal of Integrative Plant Biology 2014 56(10): 979每994
Published Online: May 5, 2014
DOI: 10.1111/jipb.12212
      
    

Anther cuticle and pollen exine act as protective envelopes for the male gametophyte or pollen grain, but the mechanism underlying the synthesis of these lipidic polymers remains unclear. Previously, a tapetum-expressed CYP703A3, a putative cytochrome P450 fatty acid hydroxylase, was shown to be essential for male fertility in rice (Oryza sativa L.). However, the biochemical and biological roles of CYP703A3 has not been characterized. Here, we observed that cyp703a3-2 caused by one base insertion in CYP703A3 displays defective pollen exine and anther epicuticular layer, which differs from Arabidopsis cyp703a2 in which only defective pollen exine occurs. Consistently, chemical composition assay showed that levels of cutin monomers and wax components were dramatically reduced in cyp703a3-2 anthers. Unlike the wide range of substrates of Arabidopsis CYP703A2, CYP703A3 functions as an in-chain hydroxylase only for a specific substrate, lauric acid, preferably generating 7-hydroxylated lauric acid. Moreover, chromatin immunoprecipitation and expression analyses revealed that the expression of CYP703A3 is directly regulated by Tapetum Degeneration Retardation, a known regulator of tapetum PCD and pollen exine formation. Collectively, our results suggest that CYP703A3 represents a conserved and diversified biochemical pathway for in-chain hydroxylation of lauric acid required for the development of male organ in higher plants.

 

Yang X, Wu D, Shi J, He Y, Pinot F, Grausem B, Yin C, Zhu L, Chen M, Luo Z, Liang W, Zhang D (2014) Rice CYP703A3, a cytochrome P450 hydroxylase, is essential for development of anther cuticle and pollen exine. J Integr Plant Biol 56: 979–994. doi: 10.1111/jipb.12212

Abstract (Browse 1237)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Molecular Ecology and Evolution
Evolution of the platycodonoid group with particular references to biogeography and character evolution
Author: Qiang Wang, Xiao-Quan Wang, Hang Sun, Yan Yu, Xing-Jin He and De-Yuan Hong
Journal of Integrative Plant Biology 2014 56(10): 995每1008
Published Online: April 5, 2014
DOI: 10.1111/jipb.12203
      
    

The Qinghai-Tibet Plateau (QTP) is an important center of origin and diversification for many northern temperate plants. The hypothesis “out-of-QTP” suggests that the majority of northern temperate plants have originated and dispersed from the QTP and adjacent regions. An interesting question is whether the biogeographic history of the platycodonoids (Campanulaceae), a group mainly distributed in the QTP and adjacent regions, coincides with the hypothesis “out-of-QTP”? Furthermore, how have the diagnostic characters of the platycodonoids evolved? In the present study, all 10 genera of the platycodonoids were sampled for molecular phylogeny and dating analyses, and ancestral states of distribution and characters were reconstructed. The results do not support the platycodonoids as an “out-of-QTP” group, but instead they might have descended from Tethyan ancestors. The dispersal and diversification of the platycodonoids in Asia might have been driven by the uplift of the QTP. The present study highlights the importance of the Tethyan Tertiary flora for the origin of the Sino-Himalayan flora and the influence of the uplift of QTP on diversification of northern temperate plants. In addition, character state reconstruction reveals that the inferior ovary, capsule, long-colpate pollen, and chromosome number 2n = 14 are probably ancestral states.

 

Wang Q, Wang XQ, Sun H, Yu Y, He XJ, Hong DY (2014) Evolution of the platycodonoid group with particular references to biogeography and character evolution. J Integr Plant Biol 56: 995–1008. doi: 10.1111/jipb.12203

Abstract (Browse 849)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Exploration of presence/absence variation and corresponding polymorphic markers in soybean genome  
Author: Yufeng Wang, Jiangjie Lu, Shouyi Chen, Liping Shu, Reid G. Palmer, Guangnan Xing, Yan Li, Shouping Yang, Deyue Yu, Tuanjie Zhao and Junyi Gai
Journal of Integrative Plant Biology 2014 56(10): 1009每1019
Published Online: April 22, 2014
DOI: 10.1111/jipb.12208
      
    

This study was designed to reveal the genome-wide distribution of presence/absence variation (PAV) and to establish a database of polymorphic PAV markers in soybean. The 33 soybean whole-genome sequences were compared to each other with that of Williams 82 as a reference genome. A total of 33,127 PAVs were detected and 28,912 PAV markers with their primer sequences were designed as the database NJAUSoyPAV_1.0. The PAVs scattered on whole genome while only 518 (1.8%) overlapped with simple sequence repeats (SSRs) in BARCSOYSSR_1.0 database. In a random sample of 800 PAVs, 713 (89.13%) showed polymorphism among the 12 differential genotypes. Using 126 PAVs and 108 SSRs to test a Chinese soybean germplasm collection composed of 828 Glycine soja Sieb. et Zucc. and Glycine max (L.) Merr. accessions, the per locus allele number and its variation appeared less in PAVs than in SSRs. The distinctness among alleles/bands of PCR (polymerase chain reaction) products showed better in PAVs than in SSRs, potential in accurate marker-assisted allele selection. The association mapping results showed SSR + PAV was more powerful than any single marker systems. The NJAUSoyPAV_1.0 database has enriched the source of PCR markers, and may fit the materials with a range of per locus allele numbers, if jointly used with SSR markers.

 

Wang Y, Lu J, Chen S, Shu L, Palmer RG, Xing G, Li Y, Yang S, Yu D, Zhao T, Gai J (2014) Exploration of presence/absence variation and corresponding polymorphic markers in soybean genome. J Integr Plant Biol 56: 1009–1019. doi: 10.1111/jipb.12208

Abstract (Browse 1360)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Genome-wide identification, evolution, and expression analysis of RNA-binding glycine-rich protein family in maize
Author: Jianhua Zhang, Yanxin Zhao, Hailin Xiao, Yonglian Zheng and Bing Yue
Journal of Integrative Plant Biology 2014 56(10): 1020每1031
Published Online: April 30, 2014
DOI: 10.1111/jipb.12210
      
    

The RNA-binding glycine-rich protein (RB-GRP) family is characterized by the presence of a glycine-rich domain arranged in (Gly)n-X repeats and an RNA-recognition motif (RRM). RB-GRPs participate in varied physiological and biochemical processes especially in the stress response of plants. In this study, a total of 23 RB-GRPs distributed on 10 chromosomes were identified in maize (Zea mays L.), and they were divided into four subgroups according to their conserved domain architecture. Five pairs of paralogs were identified, while none of them was located on the same chromosomal region, suggesting that segmental duplication is predominant in the duplication events of the RB-GRPs in maize. Comparative analysis of RB-GRPs in maize, Arabidopsis (Arabidopsis thaliana L.), rice (Oryza sativa L.), and wheat (Triticum aestivum) revealed that two exclusive subgroups were only identified in maize. Expression of eight ZmRB-GRPs was significantly regulated by at least two kinds of stresses. In addition, cis-elements predicted in the promoter regions of the ZmRB-GRPs also indicated that these ZmRB-GRPs would be involved in stress response of maize. The preliminary genome-wide analysis of the RB-GRPs in maize would provide useful information for further study on the function of the ZmRB-GRPs.

 

Zhang J, Zhao Y, Xiao H, Zheng Y, Yue B (2014) Genome坼wide identification, evolution, and expression analysis of RNA坼binding glycine坼rich protein family in maize. J Integr Plant Biol 56: 1020–1031. doi: 10.1111/jipb.12210

Abstract (Browse 787)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
 

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