植物学人|20171024-南方科技大学郭红卫揭示转录因子WRKY75，水杨酸和活性氧物质的三方扩增循环加速叶片衰老过程（推荐）
iNature：在植物学主流专刊中，主要有Plant Cell，Molecular Plant，Plant Journal，PLANT PHYSIOLOGY，NEW PHYTOLOGIST，Plant Biotech J，Plant Cell &Environ，Nature Plants等8种期刊，另外，今年出了Plant direct这一杂志，发现其地位较高，内容比较好，现在也同时进行介绍。现在经过前期的测试，iNature决定每天遴选8大植物学主刊各1篇再加上Plant direct一篇文章，共9篇文章，推送给大家，使大家能及时的了解植物学领域的动态：
Plant Cell:南方科技大学郭红卫揭示转录因子WRKY75，水杨酸和活性氧物质的三方扩增循环加速叶片衰老；
Nature Plants:剑桥大学Brockington等人揭示世界植物园里面的植物多样性的原生境保护；
Molecular Plant:马普学会Persson等人发表碳供应和细胞壁合成调节的综述；
Plant Journal:爱尔兰国立大学Spillane等人揭示亲本基因组剂量对拟南芥F1杂种三倍体胚胎转录组的影响；
PLANT PHYSIOLOGY:中国农业大学朱鸿亮等人揭示番茄正常水果成熟需要RNA编辑因子SlORRM4；
NEW PHYTOLOGIST:法国保罗·萨巴蒂尔大学Chave等人揭示树木大小和气候缺水控制全球各树种的根与茎的比率；
Plant Biotech J:奥地利维也纳自然资源与生命科学大学Buerstmayr等人揭示小麦染色体臂5AS上周围着丝粒区域的高分辨率测绘，其中包含镰刀菌枯萎病QTL Qfhs.ifa-5A位点；
Plant Cell &Environ:法国的UMR LSTM中的Prin等人揭示巴西豆科植物Piptadenia gonoacantha中高效结瘤和丛枝菌根的相互依赖关系；
Plant Direct:南京师范大学朱自强等人揭示MYC2和EIN3在拟南芥茉莉酸响应基因表达调控中的不同贡献。
1Plant Cell：南方科技大学郭红卫揭示转录因子WRKY75，水杨酸和活性氧物质的三方扩增循环加速叶片衰老
Abstract
Leaf senescence is a highly coordinated, complicated process involving the integration of numerous internal and environmental signals. Salicylic acid (SA) and reactive oxygen species (ROS) are two well-defined inducers of leaf senescence whose contents progressively and inter-dependently increase during leaf senescence via an unknown mechanism. Here, we characterized the transcription factor WRKY75 as a positive regulator of leaf senescence in Arabidopsis thaliana. Knock-down or knock-out of WRKY75 delayed age-dependent leaf senescence, while over-expression of WRKY75 accelerated this process. WRKY75 transcription is induced by age, SA, H2O2, and multiple plant hormones. Meanwhile, WRKY75 promotes SA production by inducing the transcription of SA INDUCTION-DEFICIENT2 (SID2) and suppresses H2O2 scavenging, partly by repressing the transcription of CATALASE2 (CAT2). Genetic analysis revealed that the mutation of SID2 or an increase in catalase activity rescued the precocious leaf senescence phenotype evoked by WRKY75 over-expression. Based on these results, we propose a tripartite amplification loop model in which WRKY75, SA, and ROS undergo a gradual but self-sustained rise driven by three interlinking positive feedback loops. This tripartite amplification loop provides a molecular framework connecting upstream signals, such as age and plant hormones, to the downstream regulatory network executed by SA- and H2O2-responsive transcription factors during leaf senescence.
原文链接：
http://www.plantcell.org/content/early/2017/10/23/tpc.17.00438
2Nature Plants：剑桥大学Brockington等人揭示世界植物园里面的植物多样性的原生境保护
Abstract
Botanic gardens conserve plant diversity ex situ and can prevent extinction through integrated conservation action. Here we quantify how that diversity is conserved in ex situ collections across the world’s botanic gardens. We reveal that botanic gardens manage at least 105,634 species, equating to 30% of all plant species diversity, and conserve over 41% of known threatened species. However, we also reveal that botanic gardens are disproportionately temperate, with 93% of species held in the Northern Hemisphere. Consequently, an estimated 76% of species absent from living collections are tropical in origin. Furthermore, phylogenetic bias ensures that over 50% of vascular genera, but barely 5% of non-vascular genera, are conserved ex situ. While botanic gardens are discernibly responding to the threat of species extinction, just 10% of network capacity is devoted to threatened species. We conclude that botanic gardens play a fundamental role in plant conservation, but identify actions to enhance future conservation of biodiversity.
原文链接：
https://www.nature.com/articles/s41477-017-0019-3
3Molecular Plant：马普学会Persson等人发表碳供应和细胞壁合成调节的综述
Abstract
All plant cells are surrounded by a cell wall that determines the directionality of cell growth and protects the cell against its environment. Plant cell walls are comprised primarily of polysaccharides and represent the largest sink for photosynthetically fixed carbon, both for individual plants and in the terrestrial biosphere as a whole. Cell wall synthesis is a highly complex process, involving multiple enzymes and metabolic intermediates, intracellular trafficking of proteins and cell wall precursors, assembly of the cell wall polymers into the extracellular matrix, re-modelling of polymers and their interactions, and re-cycling of cell wall sugars. In this review we explore how newly fixed carbon, in the form of UDP-glucose and other nucleotide sugars, contributes to the synthesis of cell wall polysaccharides, and how cell wall synthesis is influenced by the carbon status of the plant, with a focus on the model species Arabidopsis (Arabidopsis thaliana).
原文链接：
http://www.cell.com/molecular-plant/fulltext/S1674-2052(17)30303-9
4Plant Journal：爱尔兰国立大学Spillane等人揭示亲本基因组剂量对拟南芥F1杂种三倍体胚胎转录组的影响
Abstract
Genomic imprinting in the seed endosperm could be due to unequal parental genome contribution effects in triploid endosperm tissue that trigger parent-of-origin specific activation and/or silencing of loci prone to genomic imprinting. To determine whether genomic imprinting is triggered by unequal parental genome contribution effects, we generated a whole-genome transcriptome dataset of F1 hybrid triploid embryos (as mimics of F1 hybrid triploid endosperm). For the vast majority of genes, the parental contributions to their expression levels in the F1 triploid hybrid embryos follows a biallelic and linear expression pattern. While allele-specific expression (ASE) bias was detected, such effects were predominantly parent-of-origin independent. We demonstrate that genomic imprinting is largely absent from F1 triploid embryos, strongly suggesting that neither triploidy nor unequal parental genome contribution are key triggers of genomic imprinting in plants. However, extensive parental-genome dosage effects on gene expression were observed between the reciprocal F1 hybrid embryos, particularly for genes involved in defence response and nutrient reservoir activity, potentially leading to the seed size differences between reciprocal triploids. We further determined that unequal parental genome contribution in F1 triploids can lead to over-expression effects that are parent-of-origin dependent, and which are not observed in diploid or tetraploid embryos where the parental-genome dosage is balanced. Overall, our study demonstrates that neither triploidy nor unequal parental genome contribution are sufficient to trigger imprinting in plant tissues, suggesting that genomic imprinting is an intrinsic and unique feature of the triploid seed endosperm.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/tpj.13740/full
5PLANT PHYSIOLOGY：中国农业大学朱鸿亮等人揭示番茄正常水果成熟需要RNA编辑因子SlORRM4
Abstract
RNA editing plays a key post-transcriptional role in gene expression. Existing studies on cytidine (C)-to-uridine (U) RNA editing in plants have focused on maize, rice, and Arabidopsis. However, the importance and regulation of RNA editing in several critical agronomic processes are not well understood, a notable example of which is fruit ripening. Here, we analyzed the expression profile of 33 RNA editing factors and identified 11 putative tomato fruit ripening-related factors. A rapid virus-induced gene silencing (VIGS) assay indicated that organelle RNA recognition motif-containing protein SlORRM4 affected tomato fruit ripening. Knocking out SlORRM4 expression using a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) genome editing strategy delayed tomato fruit ripening by lowering respiratory rate and ethylene production. Additionally, the expression of numerous genes associated with fruit ripening and mitochondrial functions changed significantly when SlORRM4 was knocked out. Moreover, the loss of SlORRM4 function significantly reduced RNA editing of many mitochondrial transcripts, leading to low-level expression of some core subunits that are critical for mitochondrial complex assembly (i.e., Nad3, Cytc1, and COX II). Taken together, these results indicate that SlORRM4 is involved in RNA editing of transcripts in ripening fruit that influence mitochondrial function and key aspects of fruit ripening.
原文链接：
http://www.plantphysiol.org/content/early/2017/10/23/pp.17.01265
6NEW PHYTOLOGIST：法国保罗·萨巴蒂尔大学Chave等人揭示树木大小和气候缺水控制全球各树种的根与茎的比率
Abstract
Plants acquire carbon from the atmosphere and allocate it among different organs in response to environmental and developmental constraints (Hodge, 2004; Poorter et al., 2012). One classic example of differential allocation is the relative investment into aboveground vs belowground organs, captured by the root : shoot ratio (R : S; Cairns et al., 1997). Optimal partitioning theory suggests that plants allocate more resources to the organ that acquires the most limiting resource (Reynolds & Thornley, 1982; Johnson & Thornley, 1987). Accordingly, plants would allocate more carbon to roots if the limiting resources are belowground, that is water and nutrients, and would allocate more carbon aboveground when the limiting resource is light or CO2. This theory has been supported by recent research showing that the R : S of an individual plant is modulated by environmental factors (Poorter et al., 2012; Fatichi et al., 2014). However, understanding the mechanisms underpinning plant allocation and its response to environmental factors is an active field of research (Delpierre et al., 2016; Paul et al., 2016), and it is likely that plant size and species composition have an effect on R : S. Accounting for these sources of variation is an important challenge for modelling (Franklin et al., 2012).
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/nph.14863/full
7Plant Biotech J：奥地利维也纳自然资源与生命科学大学Buerstmayr等人揭示小麦染色体臂5AS上周围着丝粒区域的高分辨率测绘，其中包含镰刀菌 枯萎病QTL Qfhs.ifa-5A位点
Abstract
The Qfhs.ifa-5A allele, contributing to enhanced Fusarium head blight resistance in wheat, resides in a low recombinogenic region of chromosome 5A close to the centromere. A near isogenic RIL population segregating for the Qfhs.ifa-5A resistance allele was developed and among 3650 lines as few as four recombined within the pericentromeric C-5AS1-0.40 bin, yielding only a single recombination point. Genetic mapping of the pericentromeric region using a recombination dependent approach was thus not successful. To facilitate fine-mapping the physically large Qfhs.ifa-5A interval, two gamma-irradiated deletion panels were generated: (1) Seeds of line NIL3 carrying the Qfhs.ifa-5A resistance allele in an otherwise susceptible background were irradiated and plants thereof were selfed to obtain deletions in homozygous state. (2) A radiation hybrid panel was produced using irradiated pollen of the wheat line Chinese Spring (CS) for pollinating the CS-nullisomic5A tetrasomic5B. In total 5157 radiation selfing and 276 radiation hybrid plants were screened for deletions on 5AS and plants containing deletions were analysed using 102 5AS specific markers. Combining genotypic information of both panels yielded an 817 fold map improvement (cR/cM) for the centromeric bin and was 389 fold increased across the Qfhs.ifa-5A interval compared to the genetic map, with an average map resolution of 0.77 Mb/cR. We successfully proved that the RH mapping technique can effectively resolve marker order in low-recombining regions, including pericentromeric intervals, and simultaneously allow developing an in vivo panel of sister lines differing for induced deletions across the Qfhs.ifa-5A interval that can be used for phenotyping.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/pbi.12850/full
8Plant Cell &Environ：法国的UMR LSTM中的Prin等人揭示巴西豆科植物Piptadenia gonoacantha中高效结瘤和丛枝菌根的相互依赖关系
Abstract
Tripartite interactions between legumes and their root symbionts (rhizobia, arbuscular mycorrhizal fungi (AMF)) are poorly understood, although it is well established that only specific combinations of symbionts lead to optimal plant growth. A classic example in which to investigate such interactions is the Brazilian legume tree Piptadenia gonoacantha (Caesalpinioideae), for which efficient nodulation has been described as dependent on the presence of AMF symbiosis. In this study we compared the nodulation behaviour of several rhizobial strains with or without AMF inoculation, and performed analyses on nodulation, nodule cytology, N-fixing efficiency and plant growth response. Nodulation of P. gonoacantha does not rely on the presence of AMF, but mycorrhization was rhizobial strain-dependent, and nodule effectiveness and plant growth were dependent on the presence of specific combinations of rhizobial strains and AMF. The co-occurrence of both symbionts within efficient nodules, and the differentiation of bacteroids within nodule cells were also demonstrated. Novel close interactions and interdependency for the establishment and/or functioning of these symbioses were also revealed in Piptadenia thanks to immunocytochemical analyses. These data are discussed in terms of the evolutionary position of the newly-circumscribed mimosoid clade within the Caesalpinioid sub-family and its relative proximity to non-nodulated (but AMF-associated) basal subfamilies.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/pce.13095/full
9Plant Direct：南京师范大学朱自强等人揭示MYC2和EIN3在拟南芥茉莉酸响应基因表达调控中的不同贡献
Abstract
Derepression of transcription factors is the key mechanism for triggering plant jasmonate (JA) responses. Unlike regulating certain physiological functions for the majority of transcription factors in JA signaling, MYC2 and EIN3 control more diverse aspects. MYC2 predominantly participates in wounding response, metabolism, and root growth inhibition, while EIN3 (and its closest homolog EIL1) regulates defense gene expression and root hair development. Recently, it was reported that MYC2 and EIN3/EIL1 proteins mutually interact with each other and suppress their interaction partner's transcriptional activities. To understand their contributions in the modulation of transcriptomic network, we initially identified 1,495 differentially expressed jasmonate (JA)-responsive genes in wild-type Arabidopsis through RNA-seq analysis. Among them, 25% or 4.2% were independently regulated by EIN3/EIL1 or MYC2, respectively. Further analysis showed that EIN3/EIL1 and MYC2 interdependently regulate 16.3% of the JA-regulated transcriptome, including downregulation of three auxin-related genes, which might confer JA-inhibited root elongation. Lastly, we found that <30 genes were antagonistically regulated by MYC2 and EIN3/EIL1. We conclude that EIN3/EIL1 play a dominant role while MYC2 largely relies on EIN3/EIL1 for executing its transcriptional activity, either synergistically or antagonistically.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1002/pld3.15/full
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