May 2018, Volume 60 Issue 5, Pages 361-443.


Cover Caption: Glutinous rice generated by CRISPR/Cas9
Glutinous rice provides a unique characteristic for numerous food and non©\food applications. In this issue, Zhang et al. (pp. 369¨C375) show that CRISPR/Cas9©\mediated mutations in the Waxy gene convert normal rice to glutinous one without affecting other agronomic traits, offering an effective and easy way to expand genetic resources in crops.

 

          Letters to the Editor
Arabidopsis PWWP domain proteins mediate H3K27 trimethylation on FLC and regulate flowering time  
Author: Jin-Xing Zhou, Zhang-Wei Liu, Yong-Qiang Li, Lin Li, Bangjun Wang, She Chen and Xin-Jian He
Journal of Integrative Plant Biology 2018 60(5): 362-368
Published Online: January 4, 2018
DOI: 10.1111/jipb.12630
      
    

LHP1 mediates recruitment of the PRC2 histone methyltransferase complex to chromatin and thereby facilitates maintenance of H3K27me3 on FLC, a key flowering repressor gene. Here, we report that the PWWP domain proteins (PDPs) interact with FVE and MSI5 to suppress FLC expression and thereby promote flowering. We demonstrated that FVE, MSI5, and PDP3 were co©\purified with LHP1. The H3K27me3 level on FLC was decreased in the pdp mutants as well as in the fve/msi5 double mutant. This study suggests that PDPs function together with FVE and MSI5 to regulate the function of the PRC2 complex on FLC.

Abstract (Browse 369)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
We demonstrate that PWWP domain proteins are previously uncharacterized flowering time regulators in Arabidopsis. The PWWP domain proteins interact with the known flowering time regulators FVE and MSI5 and thus facilitate histone H3K27 trimethylation on the key flowering time repressor gene FLC to promote flowering.
Generation of new glutinous rice by CRISPR/Cas9©\targeted mutagenesis of the Waxy gene in elite rice varieties  
Author: Jinshan Zhang, Hui Zhang, Jos¨¦ Ram¨®n Botella and Jian-Kang Zhu
Journal of Integrative Plant Biology 2018 60(5): 369-375
Published Online: December 6, 2017
DOI: 10.1111/jipb.12620
      
    

In rice, amylose content (AC) is controlled by a single dominant Waxy gene. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR©\associated 9 (Cas9) to introduce a loss©\of©\function mutation into the Waxy gene in two widely cultivated elite japonica varieties. Our results show that mutations in the Waxy gene reduce AC and convert the rice into glutinous ones without affecting other desirable agronomic traits, offering an effective and easy strategy to improve glutinosity in elite varieties. Importantly, we successfully removed the transgenes from the progeny. Our study provides an example of generating improved crops with potential for commercialization, by editing a gene of interest directly in elite crop varieties.

Abstract (Browse 702)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
In this study, we reported generation of new glutinous rice with potential for commercialization by editing Waxy gene in elite crop varieties.
Multigene editing via CRISPR/Cas9 guided by a single©\sgRNA seed in Arabidopsis  
Author: Zhiming Yu, Qiyuan Chen, Weiwei Chen, Xian Zhang, Fengling Mei, Pengcheng Zhang, Mei Zhao, Xiaohong Wang, Nongnong Shi, Stephen Jackson and Yiguo Hong
Journal of Integrative Plant Biology 2018 60(5): 376-381
Published Online: December 11, 2017
DOI: 10.1111/jipb.12622
      
    

We report that a solo single©\guide RNA (sgRNA) seed is capable of guiding Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR −associated 9 (CRISRP/Cas9) to simultaneously edit multiple genes AtRPL10A, AtRPL10B and AtRPL10C in Arabidopsis. Our results also demonstrate that it is possible to use CRISPR/Cas9 technology to create AtRPL10 triple mutants which otherwise cannot be generated by conventional genetic crossing. Compared to other conventional multiplex CRISPR/Cas systems, a single sgRNA seed has the advantage of reducing off©\target gene©\editing. Such a gene editing system might be also applicable to modify other homologous genes, or even less©\homologous sequences for multiple gene©\editing in plants and other organisms.

Abstract (Browse 428)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
A single©\sgRNA seed is capable of guiding CRISPR/Cas9 to simultaneously edit multiple genes AtRPL10A, AtRPL10B and AtRPL10C in Arabidopsis. Our results imply that such a multi©\gene editing system might be also applicable to modifying other homologous genes or even less©\homologous sequences in plants and other organisms.
          New Technology
Method for hull©\less barley transformation and manipulation of grain mixed©\linkage beta©\glucan  
Author: Wai Li Lim, Helen M. Collins, Rohan R. Singh, Natalie A. J. Kibble, Kuok Yap, Jillian Taylor, Geoffrey B. Fincher and Rachel A. Burton
Journal of Integrative Plant Biology 2018 60(5): 382-396
Published Online: December 16, 2017
DOI: 10.1111/jipb.12625
      
    

Hull©\less barley is increasingly offering scope for breeding grains with improved characteristics for human nutrition; however, recalcitrance of hull©\less cultivars to transformation has limited the use of these varieties. To overcome this limitation, we sought to develop an effective transformation system for hull©\less barley using the cultivar Torrens. Torrens yielded a transformation efficiency of 1.8%, using a modified Agrobacterium transformation method. This method was used to over©\express genes encoding synthases for the important dietary fiber component, (1,3;1,4)©\β©\glucan (mixed©\linkage glucan), primarily present in starchy endosperm cell walls. Over©\expression of the HvCslF6 gene, driven by an endosperm©\specific promoter, produced lines where mixed©\linkage glucan content increased on average by 45%, peaking at 70% in some lines, with smaller increases in transgenic HvCslH1 grain. Transgenic HvCslF6 lines displayed alterations where grain had a darker color, were more easily crushed than wild type and were smaller. This was associated with an enlarged cavity in the central endosperm and changes in cell morphology, including aleurone and sub©\aleurone cells. This work provides proof©\of©\concept evidence that mixed©\linkage glucan content in hull©\less barley grain can be increased by over©\expression of the HvCslF6 gene, but also indicates that hull©\less cultivars may be more sensitive to attempts to modify cell wall composition.

Abstract (Browse 540)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Hull©\less barley is increasingly offering scope for breeding grains with improved characteristics for human nutrition. We have developed a transformation system for hull©\less barley. This was used to over©\express a gene (HvCslF6) encoding a synthase for mixed©\linkage glucan. This produced lines with an increased mixed©\linkage glucan of 45% on average.
          Metabolism and Biochemistry
Metabolic responses of Eucalyptus species to different temperature regimes  
Author: Joao Benhur Mokochinski, Paulo Mazzafera, Alexandra Christine Helena Frankland Sawaya, Roland Mumm, Ric Cornelis Hendricus de Vos and Robert David Hall
Journal of Integrative Plant Biology 2018 60(5): 397-411
Published Online: December 16, 2017
DOI: 10.1111/jipb.12626
      
    

Species and hybrids of Eucalyptus are the world's most widely planted hardwood trees. They are cultivated across a wide range of latitudes and therefore environmental conditions. In this context, comprehensive metabolomics approaches have been used to assess how different temperature regimes may affect the metabolism of three species of Eucalyptus, E. dunnii, E. grandis and E. pellita. Young plants were grown for 53 d in the greenhouse and then transferred to growth chambers at 10°C, 20°C or 30°C for another 7 d. In all three species the leaf chlorophyll content was positively correlated to temperature, and in E. pellita the highest temperature also resulted in a significant increase in stem biomass. Comprehensive metabolomics was performed using untargeted gas chromatography mass spectrometry (GC©\MS) and liquid chromatography (LC)©\MS. This approach enabled the comparison of the relative abundance of 88 polar primary metabolites from GC©\MS and 625 semi©\polar secondary metabolites from LC©\MS. Using principal components analysis, a major effect of temperature was observed in each species which was larger than that resulting from the genetic background. Compounds mostly affected by temperature treatment were subsequently selected using partial least squares discriminant analysis and were further identified. These putative annotations indicated that soluble sugars and several polyphenols, including tannins, triterpenes and alkaloids were mostly influenced.

Abstract (Browse 365)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
The effect of different temperatures on three contrasting Eucalyptus species was evaluated by advanced metabolomics techniques. Even short exposures to suboptimal temperatures affected physiologically the tested species. Metabolomics analysis further revealed that temperature plays an important role in Eucalyptus growth.
          Molecular Ecology and Evolution
Elevated CO2 differentially affects tobacco and rice defense against lepidopteran larvae via the jasmonic acid signaling pathway
Author: Chengkai Lu, Jinfeng Qi, Christian Hettenhausen, Yunting Lei, Jingxiong Zhang, Mou Zhang, Cuiping Zhang, Juan Song, Jing Li, Guoyan Cao, Saif ul Malook and Jianqiang Wu
Journal of Integrative Plant Biology 2018 60(5): 412-431
Published Online: January 10, 2018
DOI: 10.1111/jipb.12633
      
    

Atmospheric CO2 levels are rapidly increasing due to human activities. However, the effects of elevated CO2 (ECO2) on plant defense against insects and the underlying mechanisms remain poorly understood. Here we show that ECO2 increased the photosynthetic rates and the biomass of tobacco and rice plants, and the chewing lepidopteran insects Spodoptera litura and Mythimna separata gained less and more mass on tobacco and rice plants, respectively. Consistently, under ECO2, the levels of jasmonic acid (JA), the main phytohormone controlling plant defense against these lepidopteran insects, as well as the main defense©\related metabolites, were increased and decreased in insect©\damaged tobacco and rice plants. Importantly, bioassays and quantification of defense©\related metabolites in tobacco and rice silenced in JA biosynthesis and perception indicate that ECO2 changes plant resistance mainly by affecting the JA pathway. We further demonstrate that the defensive metabolites, but not total N or protein, are the main factors contributing to the altered defense levels under ECO2. This study illustrates that ECO2 changes the interplay between plants and insects, and we propose that crops should be studied for their resistance to the major pests under ECO2 to predict the impact of ECO2 on future agroecosystems.

Abstract (Browse 269)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Atmospheric CO2 is rapidly increasing. We show that increased CO2 positively and negatively alters the defenses of tobacco and rice against caterpillar insects respectively, by increasing and decreasing insect feeding©\induced jasmonic acid. This study highlights the potential impact of increased atmospheric CO2 on future agricultural and natural ecosystems.
          Plant-biotic Interactions
A novel wheat NAC transcription factor, TaNAC30, negatively regulates resistance of wheat to stripe rust
Author: Bing Wang, Jinping Wei, Na Song, Ning Wang, Jing Zhao and Zhensheng Kang
Journal of Integrative Plant Biology 2018 60(5): 432-443
Published Online: December 18, 2017
DOI: 10.1111/jipb.12627
      
    

NAC transcription factors are widespread in the plant kingdom and play essential roles in the transcriptional regulation of defense responses. In this study, we isolated a novel NAC transcription factor gene, TaNAC30, from a cDNA library constructed from wheat (Triticum aestivum) plants inoculated with the stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst). TaNAC30 contains a typical NAM domain and localizes to the nucleus. Yeast one©\hybrid assays revealed that TaNAC30 exhibits transcriptional activity and that its C©\terminus is necessary for the activation of transcription. Expression of TaNAC30 increased when host plants were infected with a virulent race (CYR31) of the rust fungus Pst. Silencing of TaNAC30 by virus©\induced gene silencing inhibited colonization of the virulent Pst isolate CYR31. Moreover, detailed histological analyses showed that silencing of TaNAC30 enhanced resistance to Pst by inducing a significant increase in the accumulation of H2O2. Finally, we overexpressed TaNAC30 in fission yeast and determined that cell viability was severely reduced in TaNAC30©\transformed cells grown on medium containing H2O2. These results suggest that TaNAC30 negatively regulates plant resistance in a compatible wheat©\Pst interaction.

Abstract (Browse 300)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
TaNAC30 contains a typical NAM domain and localizes to the nucleus. Silencing of TaNAC30 enhanced resistance to the stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst) by inducing a significant increase in the accumulation of H2O2. TaNAC30 negatively regulates plant resistance in a compatible wheat©\Pst interaction.
 
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