Early View

  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
Received: September 30, 2017         Accepted: January 2, 2018
Online Date: 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 204)   |   References   |   Full Text HTML   |   Full Text PDF       
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
Received: November 14, 2017         Accepted: December 7, 2017
Online Date: 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 209)   |   References   |   Full Text HTML   |   Full Text PDF       
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
Received: November 23, 2017         Accepted: December 1, 2017
Online Date: 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 199)   |   References   |   Full Text HTML   |   Full Text PDF       
  Functional Omics and Systems Biology
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
Received: August 29, 2017         Accepted: December 14, 2017
Online Date: 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 210)   |   References   |   Full Text HTML   |   Full Text PDF       
  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
Received: October 9, 2017         Accepted: January 5, 2018
Online Date: 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 128)   |   References   |   Full Text HTML   |   Full Text PDF       
  New Technology
Calcium imaging in Arabidopsis pollen cells using G©\CaMP5
Author: Min Diao, Xiaolu Qu and Shanjin Huang
Received: January 17, 2018         Accepted: February 7, 2018
Online Date: February 9, 2018
DOI: 10.1111/jipb.12642

Calcium (Ca2+) signaling has been implicated in pollen germination and pollen tube growth. To date, however, we still know very little about how exactly Ca2+ signaling links to various physiological subcellular processes during pollen germination and pollen tube growth. Given that Ca2+ signaling is tightly related to the cytosolic concentration and dynamics of Ca2+, it is vital to trace the dynamic changes in Ca2+ levels in order to decode Ca2+ signaling. Here, we demonstrate that G©\CaMP5 serves well as an indicator for monitoring cytosolic Ca2+ dynamics in pollen cells. Using this probe, we show that cytosolic Ca2+ changes dramatically during pollen germination, and, as reported previously, Ca2+ forms a tip©\focused gradient in the pollen tube and undergoes oscillation in the tip region during pollen tube growth. In particular, using G©\CaMP5 allowed us to capture the dynamic changes in the cytosolic Ca2+ concentration ([Ca2+]cyt) in pollen tubes in response to various exogenous treatments. Our data suggest that G©\CaMP5 is a suitable probe for monitoring the dynamics of [Ca2+]cyt in pollen cells.

Abstract (Browse 117)   |   References   |   Full Text HTML   |   Full Text PDF       
Method for hull-less barley transformation and manipulation of grain with 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
Received: November 15, 2017         Accepted: December 13, 2017
Online Date: 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 148)   |   References   |   Full Text HTML   |   Full Text PDF       
  Photosynthesis and Crop Physiology
ZmCOL3, a CCT gene represses flowering in maize by interfering with the circadian clock and activating expression of ZmCCT
Author: Minliang Jin, Xiangguo Liu, Wei Jia, Haijun Liu, Wenqiang Li, Yong Peng, Yanfang Du, Yuebin Wang, Yuejia Yin, Xuehai Zhang, Qing Liu, Min Deng, Nan Li, Xiyan Cui, Dongyun Hao and Jianbing Yan
Received: December 16, 2017         Accepted: January 9, 2018
Online Date: January 10, 2018
DOI: 10.1111/jipb.12632

Flowering time is a trait vital to the adaptation of flowering plants to different environments. Here, we report that CCT domain genes play an important role in flowering in maize (Zea mays L.). Among the 53 CCT family genes we identified in maize, 28 were located in flowering time quantitative trait locus regions and 15 were significantly associated with flowering time, based on candidate-gene association mapping analysis. Furthermore, a CCT gene named ZmCOL3 was shown to be a repressor of flowering. Overexpressing ZmCOL3 delayed flowering time by approximately 4 d, in either long-day or short-day conditions. The absence of one cytosine in the ZmCOL3 3'UTR and the presence of a 551 bp fragment in the promoter region are likely the causal polymorphisms contributing to the maize adaptation from tropical to temperate regions. We propose a modified model of the maize photoperiod pathway, wherein ZmCOL3 acts as an inhibitor of flowering either by transactivating transcription of ZmCCT, one of the key genes regulating maize flowering, or by interfering with the circadian clock.

Abstract (Browse 135)   |   References   |   Full Text HTML   |   Full Text PDF       
  Molecular Physiology
Cellulose synthase ¡®class specific regions¡¯ are intrinsically disordered and functionally undifferentiated
Author: Tess R. Scavuzzo-Duggan, Arielle M. Chaves, Abhishek Singh, Latsavongsakda Sethaphong, Erin Slabaugh, Yaroslava G. Yingling, Candace H. Haigler and Alison W. Roberts
Received: November 4, 2017         Accepted: January 27, 2018
Online Date: January 30, 2018
DOI: 10.1111/jipb.12637

Cellulose synthases (CESAs) are glycosyltransferases that catalyze formation of cellulose microfibrils in plant cell walls. Seed plant CESA isoforms cluster in six phylogenetic clades, whose non-interchangeable members play distinct roles within Cellulose Synthesis Complexes (CSCs). A 'class specific region' (CSR) with higher sequence similarity within vs. between functional CESA classes has been suggested to contribute to specific activities or interactions of different isoforms. We investigated CESA isoform specificity in the moss Physcomitrella patens (Hedw.) B. S. G. to gain evolutionary insights into CESA structure/function relationships. Like seed plants, P. patens has oligomeric rosette-type CSCs, but the PpCESAs diverged independently and form a separate CESA clade. We showed that P. patens has two functionally distinct CESAs classes based on the ability to complement the gametophore-negative phenotype of a ppcesa5 knockout line. Thus, non-interchangeable CESA classes evolved separately in mosses and seed plants. However, testing of chimeric moss CESA genes for complementation demonstrated that functional class-specificity is not determined by the CSR. Sequence analysis and computational modeling showed that the CSR is intrinsically disordered and contains predicted Molecular Recognition Features, consistent with a possible role in CESA oligomerization and explaining the evolution of class-specific sequences without selection for class-specific function.

Abstract (Browse 101)   |   References   |   Full Text HTML   |   Full Text PDF       
Silencing GRAS2 reduces fruit weight in tomato
Author: Miao Li, Xin Wang, Changxing Li, Hanxia Li, Junhong Zhang and Zhibiao Ye
Received: October 30, 2017         Accepted: January 9, 2018
Online Date: January 23, 2018
DOI: 10.1111/jipb.12636

GRAS family transcription factors are involved in multiple biological processes in plants. Here, we report that GRAS2 plays a vital role in regulating fruit weight in tomato (Solanum lycopersicum). We establish that the expression of GRAS2 was elevated in ovaries and maintained at a constant level in fertilized ovules. Reduction of GRAS2 expression in transgenic plants reduced fruit weight through modulating ovary growth and cell size. At the metabolic level, downregulation of GRAS2 decreased activities of the gibberellic acid biosynthesis and signal transduction pathways, leading to insufficient levels of active gibberellic acid during the initial ovary development of tomato. Moreover, genotypic diversity of GRAS2 was consistent with the molecular basis of fruit weight evolution, suggesting that GRAS2 contributes to the molecular basis of the evolution of fruit weight in tomato. Collectively, these findings enhance our understanding of GRAS2 functions, in fruit development of tomato, and demonstrate a strong association between the GRAS gene family and fruit development.

Abstract (Browse 92)   |   References   |   Full Text HTML   |   Full Text PDF       
  Plant-abiotic 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
Received: November 21, 2017         Accepted: December 18, 2017
Online Date: 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 161)   |   References   |   Full Text HTML   |   Full Text PDF       

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