植物学人|20171023-南京农业大学陶小荣等人揭示细胞内免疫受体SW-5B赋予抗广谱丝虫病的机制（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。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（福利版），共8篇文章，推送给大家，使大家能及时地了解植物学领域的动态：
Plant Cell:南京农业大学陶小荣等人揭示细胞内免疫受体SW-5B赋予抗广谱丝虫病，那是通过该细胞内免疫受体SW-5B赋予广谱抗丝虫病通过识别病毒保守的21个氨基酸的表位效应物；
Nature Plants:John Innes Centre的Sablowski等人揭示DELLA基因限制花序分生组织功能独立于植物高度；
Molecular Plant:澳大利亚昆士兰大学Hickey等人揭示VERNALIZATION1调节小麦和大麦的根系生长；
Plant Journal:内布拉斯加大学林肯分校Sarath等人揭示柳树的地下部分可以季节性的代谢；
PLANT PHYSIOLOGY:美国的爱荷华州立大学Bassham等人发表自噬体形成自噬动力学的综述；
NEW PHYTOLOGIST:四川农业大学杨文钰等人发表APETALA 2结构域的转录因子：侧重于脱落酸和赤霉素拮抗作用的“小综述”；
Plant Biotech J:英国牛津大学Hoorn等人农杆菌渗透的本氏烟草的转录组，细胞外蛋白质组和活性分泌物揭示了一种大的及多样的蛋白酶库；
Plant Cell &Environ:加拿大莱斯布里奇研究中心Acharya苜蓿的分子改良，以提高生产力和变化环境中的适应性的综述。
1Plant Cell：南京农业大学陶小荣等人揭示细胞内免疫受体SW-5B赋予抗广谱丝虫病，那是通过该细胞内免疫受体SW-5B赋予广谱抗丝虫病通过识别病毒保守的21个氨基酸的表位效应物
Abstract
Plants use both cell surface-resident pattern recognition receptors (PRRs) and intracellular nucleotide binding leucine-rich repeat (NLR) receptors to detect various pathogens. Plant PRRs typically recognize conserved pathogen-associated molecular patterns (PAMPs) to provide broad-spectrum resistance. By contrast, plant NLRs generally detect pathogen strain-specific effectors and confer race-specific resistance. Here, we demonstrate that the tomato (Solanum lycopersicum) NLR Sw-5b confers broad-spectrum resistance against American-type tospoviruses by recognizing a conserved 21-amino acid peptide region within viral movement protein NSm (NSm21). Sw-5b NB-ARC-LRR domains directly associate with NSm21 in vitro and in planta. Domain swap, site-directed mutagenesis and structure modeling analyses identified four polymorphic sites in the Sw-5b LRR domain that are critical for the recognition of NSm21. Furthermore, recognition of NSm21 by Sw-5b likely disturbs the residues adjacent to R927 in the LRR domain to weaken the intramolecular interaction between LRR and NB-ARC domains, thus translating recognition of NSm21 into activation of Sw-5b. Natural variation analysis of Sw-5b homologs from wild tomato species of South America revealed that the four polymorphic sites in the Sw-5b LRR domain were positively selected during evolution and are all necessary to confer resistance to tospovirus. The results described here provide a new example of a plant NLR mediating broad-spectrum resistance through recognition of a small conserved PAMP-like region within the pathogen effector.
原文链接：
http://www.plantcell.org/content/29/9/2214
2Nature Plants：John Innes Centre的Sablowski等人揭示DELLA基因限制花序分生组织功能独立于植物高度
Abstract
DELLA proteins associate with transcription factors to control plant growth in response to gibberellin. Semi-dwarf DELLA mutants with improved harvest index and decreased lodging greatly improved global food security during the ‘green revolution’ in the 1960–1970s. However, DELLA mutants are pleiotropic and the developmental basis for their effects on plant architecture remains poorly understood. Here, we show that DELLA proteins have genetically separable roles in controlling stem growth and the size of the inflorescence meristem, where flowers initiate. Quantitative three-dimensional image analysis, combined with a genome-wide screen for DELLA-bound loci in the inflorescence tip, revealed that DELLAs limit meristem size in Arabidopsis by directly upregulating the cell-cycle inhibitor KRP2 in the underlying rib meristem, without affecting the canonical WUSCHEL-CLAVATA meristem size regulators. Mutation of KRP2 in a DELLA semi-dwarf background restored meristem size, but not stem growth, and accelerated flower production. In barley, secondary mutations in the DELLA gain-of-function mutant Sln1d also uncoupled meristem and inflorescence size from plant height. Our work reveals an unexpected and conserved role for DELLA genes in controlling shoot meristem function and suggests how dissection of pleiotropic DELLA functions could unlock further yield gains in semi-dwarf mutants.
原文链接：
https://www.nature.com/articles/s41477-017-0003-y
3Molecular Plant：澳大利亚昆士兰大学Hickey等人揭示VERNALIZATION1调节小麦和大麦的根系生长
Abstract
Roots play a key role in plant growth regulation. It is well described that the belowground plant architecture significantly impacts plant performance under abiotic constraints and maintains stability under increased grain load .
Although loci influencing root traits have been shown to impact grain yield and
agronomic performance (e.g. Canè et al., 2014), knowledge about the genetic
control of root growth in major grain crops is limited. Here we demonstrate that
VERNALIZATION1 (VRN1), a key regulator of flowering behaviour in cereals , also modulates root architecture in wheat and barley. Our discoveries provide unexpected insight into underground functions of a major player in the flowering pathway.
原文链接：
http://www.cell.com/molecular-plant/fulltext/S1674-2052(17)30304-0
4Plant Journal：内布拉斯加大学林肯分校Sarath等人揭示柳树的地下部分可以季节性的代谢
Abstract
Switchgrass (Panicum virgatum), a perennial, polyploid, C4 warm-season grass is among the foremost herbaceous species being advanced as a source of biomass for biofuel end uses. At the end of every growing season, the aerial tissues senesce, and the below-ground rhizomes become dormant. Future growth is dependent on the successful over-wintering of the rhizomes. Although the importance of rhizome health to overall year-upon-year plant productivity has been long recognized, there is limited information on seasonal changes occurring during dormancy at both the transcriptome and metabolite levels. Here, global changes in transcriptomes and metabolites were investigated over two growing seasons in rhizomes harvested from field-grown plants. The objectives were (a) synthesize information on cellular processes that lead to dormancy and to (b) provide models that could account for major metabolic pathways present in dormant switchgrass rhizomes. Overall, metabolism during dormancy appeared to involve discrete but interrelated events. One was a response to ABA that resulted in dehydration, increases in osmolytes, and upregulation of autophagic processes, likely through the target of rapamycin complex and sucrose non-fermentative related kinase based signaling cascades. Another was a recalibration of energy transduction through apparent reductions in mitochondrial oxidative phosphorylation, increases in substrate level generation of ATP and reducing equivalents, and recycling of N and possibly CO2 through refixation. Lastly, transcript abundances indicated that cold-related signaling was also occurring. Altogether, these data provide a detailed overview of rhizome metabolism, especially during dormancy, which can be exploited in the future to improve winter survival in switchgrass.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/tpj.13742/full
5PLANT PHYSIOLOGY：美国的爱荷华州立大学Bassham等人发表自噬体形成自噬动力学的综述
Abstract
Autophagy, literally defined as “self-eating”, functions as a degradation process by recycling cytoplasmic contents under stress conditions or during development. Upon activation of autophagy, a membrane structure known as a phagophore forms and expands, finally closing to form a double-membrane vesicle called an autophagosome. The completed autophagosome, which contains the autophagic cargo, is delivered to the vacuole (plants and yeast) or lysosome (animals). The outer membrane fuses with the vacuolar/lysosomal membrane and the inner membrane and contents are released into the
vacuole/lysosome as an autophagic body and are degraded by hydrolases. The breakdown products are transported back into the cytoplasm for reuse by the cell.
原文链接：
http://www.plantphysiol.org/content/early/2017/10/23/pp.17.01236
6NEW PHYTOLOGIST：四川农业大学杨文钰等人发表APETALA 2结构域的转录因子：侧重于脱落酸和赤霉素拮抗作用的“小综述”
Abstract
The phytohormones abscisic acid (ABA) and gibberellin (GA) antagonistically mediate diverse plant developmental processes including seed dormancy and germination, root development, and flowering time control, and thus the optimal balance between ABA and GA is essential for plant growth and development. Although more than a half and one century have passed since the initial discoveries of ABA and GA, respectively, the precise mechanisms underlying ABA–GA antagonism still need further investigation. Emerging evidence indicates that two APETALA 2 (AP2)-domain-containing transcription factors (ATFs), ABI4 in Arabidopsis and OsAP2-39 in rice, play key roles in ABA and GA antagonism. These two transcription factors precisely regulate the transcription pattern of ABA and GA biosynthesis or inactivation genes, mediating ABA and GA levels. In this Viewpoint article, we try to shed light on the effects of ATFs on ABA–GA antagonism, and summarize the overlapping but distinct biological functions of these ATFs in the antagonism between ABA and GA. Finally, we strongly propose that further research is needed into the detailed roles of additional numerous ATFs in ABA and GA crosstalk, which will improve our understanding of the antagonism between these two phytohormones.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/nph.14880/full
7Plant Biotech J：英国牛津大学Hoorn等人农杆菌渗透的本氏烟草的转录组，细胞外蛋白质组和活性分泌物揭示了一种大的及多样的蛋白酶库
Abstract
Infiltration of disarmed Agrobacterium tumefaciens into leaves of Nicotiana benthamiana (agroinfiltration) facilitates quick and safe production of antibodies, vaccines, enzymes and metabolites for industrial use (Molecular Farming). However, yield and purity of proteins produced by agroinfiltration are hampered by unintended proteolysis, restricting industrial viability of the agroinfiltration platform. Proteolysis may be linked to an immune response to agroinfiltration, but understanding of the response to agroinfiltration is limited. To identify the proteases, we studied the transcriptome, extracellular proteome and active secretome of agroinfiltrated leaves over a time course, with and without the P19 silencing inhibitor. Remarkably, P19 expression had little effect on the leaf transcriptome and no effect on the extracellular proteome. 25% of the detected transcripts changed in abundance upon agroinfiltration, associated with a gradual upregulation of immunity at the expense of photosynthesis. By contrast, 70% of the extracellular proteins increase in abundance, in many cases associated with increased efficiency of extracellular delivery. We detect a dynamic reprogramming of the proteolytic machinery upon agroinfiltration by detecting transcripts encoding for 975 different proteases and protease-homologs. The extracellular proteome contains peptides derived from 196 proteases and protease homologs, and activity-based proteomics displayed 17 active extracellular Ser and Cys proteases in agroinfiltrated leaves. We discuss unique features of the N. benthamiana protease repertoire and highlight abundant extracellular proteases in agroinfiltrated leaves, being targets for reverse genetics. This dataset increases our understanding of the plant response to agroinfiltration and indicates ways to improve a key expression platform for both plant science and Molecular Farming.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/pbi.12852/full
8Plant Cell &Environ：加拿大莱斯布里奇研究中心Acharya苜蓿的分子改良，以提高生产力和变化环境中的适应性的综述
Abstract
Due to an expanding world population and increased buying power, the demand for ruminant products such as meat and milk is expected to grow substantially in coming years and high levels of forage crop production will therefore be a necessity. Unfortunately, urbanization of agricultural land, intensive agricultural practices, and climate change are all predicted to limit crop production in the future, which means that the development of forage cultivars with improved productivity and adaptability will be essential. Since alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage crops, it has been the target of much research in this field. In this review, we discuss progress that has been made towards the improvement of productivity, abiotic stress tolerance, and nutrient-use efficiency, as well as disease and pest resistance, in alfalfa using biotechnological techniques. Furthermore, we consider possible future priorities and avenues for attaining further enhancements in this crop as a means of contributing to the realization of food security in a changing environment.
原文链接：
http://onlinelibrary.wiley.com/doi/10.1111/pce.13090/full
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