植物学人|20171019-美国科学院院士陈雪梅发表植物microRNA综述（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，使大家能及时的了解植物学领域的动态：

Plant Cell:意大利米兰大学Fornara等人揭示在水稻中拮抗转录因子复合物调节开花过程；

Nature Plants:日本东京大学Nureki等人揭示磷酸转运蛋白转运磷酸的分子机制；

Molecular Plant:剑桥大学Wigge等人揭示H2A.Z和HSF1转录因子在拟南芥中对于环境温度响应的转录调控；

Plant Journal:韩国首尔国立大学Paek等人揭示ELF3抑制盐胁迫途径；

PLANT PHYSIOLOGY:法国巴黎狄德罗大学Frugier等人揭示DELLA介导的赤霉素信号调节细胞分裂素依赖性共生结瘤；

NEW PHYTOLOGIST:美国科学院院士陈雪梅发表植物microRNA综述；

Plant Biotech J:中科院热带农业科学院（海口）Jin等人揭示MuMADS1和MaOFP1调节番茄卵裂突变体的水果质量；

Plant Cell &Environ:浙江大学喻景权等人揭示番茄CRY1a在调控水果中的植物激素体内平衡，植物发育和类胡萝卜素代谢中起关键作用。

1Plant Cell：意大利米兰大学Fornara等人揭示在水稻中拮抗转录因子复合物调节开花过程

Abstract

Plants measure day or night lengths to coordinate specific developmental changes with a favorable season. In rice (Oryza sativa), the reproductive phase is initiated by exposure to short days when expression of HEADING DATE 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1) is induced in leaves. The cognate proteins are components of the florigenic signal, and move systemically through the phloem to reach the shoot apical meristem (SAM). In the SAM, they form a transcriptional activation complex with the bZIP transcription factor OsFD1, to start panicle development. Here, we show that Hd3a and RFT1 can form transcriptional activation or repression complexes also in leaves, and feed-back to regulate their own transcription. Activation complexes depend upon OsFD1 to promote flowering. However, additional bZIPs, including Hd3a BINDING REPRESSOR FACTOR 1 (HBF1) and HBF2 form repressor complexes that reduce Hd3a and RFT1 expression to delay flowering. We propose that Hd3a and RFT1 are also active locally in leaves to fine-tune photoperiodic flowering responses.

原文链接：

http://www.plantcell.org/content/early/2017/10/17/tpc.17.00645

2Nature Plants：日本东京大学Nureki等人揭示磷酸转运蛋白转运磷酸的分子机制

Abstract

The triose-phosphate/phosphate translocator (TPT) catalyses the strict 1:1 exchange of triose-phosphate, 3-phosphoglycerate and inorganic phosphate across the chloroplast envelope, and plays crucial roles in photosynthesis. Despite rigorous study for more than 40 years, the molecular mechanism of TPT is poorly understood because of the lack of structural information. Here we report crystal structures of TPT bound to two different substrates, 3-phosphoglycerate and inorganic phosphate, in occluded conformations. The structures reveal that TPT adopts a 10-transmembrane drug/metabolite transporter fold. Both substrates are bound within the same central pocket, where conserved lysine, arginine and tyrosine residues recognize the shared phosphate group. A structural comparison with the outward-open conformation of the bacterial drug/metabolite transporter suggests a rocker-switch motion of helix bundles, and molecular dynamics simulations support a model in which this rocker-switch motion is tightly coupled to the substrate binding, to ensure strict 1:1 exchange. These results reveal the unique mechanism of sugar phosphate/phosphate exchange by TPT.

原文链接：

https://www.nature.com/articles/s41477-017-0022-8

3Molecular Plant：剑桥大学Wigge等人揭示H2A.Z和HSF1转录因子在拟南芥中对于环境温度响应的转录调控

Abstract

Temperature influences the distribution, range, and phenology of plants. The key transcriptional activators of heat shock response in eukaryotes, the heat shock factors (HSFs), have undergone large-scale gene amplification in plants. While HSFs are central in heat stress responses, their role in the response to ambient temperature changes is less well understood. We show here that the warm ambient temperature transcriptome is dependent upon the HSFA1 clade of Arabidopsis HSFs, which cause a rapid and dynamic eviction of H2A.Z nucleosomes at target genes. A transcriptional cascade results in the activation of multiple downstream stress-responsive transcription factors, triggering large-scale changes to the transcriptome in response to elevated temperature. H2A.Z nucleosomes are enriched at temperature-responsive genes at non-inducible temperature, and thus likely confer inducibility of gene expression and higher responsive dynamics. We propose that the antagonistic effects of H2A.Z and HSF1 provide a mechanism to activate gene expression rapidly and precisely in response to temperature, while preventing leaky transcription in the absence of an activation signal.

原文链接：

http://www.cell.com/molecular-plant/fulltext/S1674-2052(17)30245-9

4Plant Journal：韩国首尔国立大学Paek等人揭示ELF3抑制盐胁迫途径

Abstract

Arabidopsis EARLY FLOWERING3 (ELF3) functions in modulating light input to the circadian clock, as a component of ELF3-ELF4-LUX ARRHYTHMO (LUX) evening complex. However, the role of ELF3 in stress responses remains largely unknown. In this study, we show that ELF3 enhances plants’ resilience to salt stress: ELF3-overexpressing (ELF3-OX) plants are salt-tolerant while elf3 mutants are more sensitive to salt stress. Expression of many salt stress- and senescence-associated genes are altered in elf3-1 and ELF3-OX plants compared to wild type. During salt stress, ELF3 suppresses factors that promote salt stress response pathways, mainly GIGANTEA (GI), at the post-translational level, and PHYTOCHROME INTERACTING FACTOR4(PIF4), at the transcriptional level. To enhance the salt stress response, PIF4 directly downregulates the transcription of JUNGBRUNNEN1 (JUB1/ANAC042), encoding a transcription factor that upregulates the expression of stress tolerance genes, DREB2A and DELLA. Furthermore, PIF4 directly upregulates the transcription of ORESARA1 (ORE1/ANAC092) and SAG29, positive regulators of salt stress response pathways. Based on our results, we propose that ELF3 modulates key regulatory components in salt stress response pathways at the transcriptional and posttranslational levels.

原文链接：

http://onlinelibrary.wiley.com/doi/10.1111/tpj.13747/full

5PLANT PHYSIOLOGY：法国巴黎狄德罗大学Frugier等人揭示DELLA介导的赤霉素信号调节细胞分裂素依赖性共生结瘤

Abstract

In legume plants, low nitrogen soils promote symbiotic interactions with rhizobial bacteria, leading to the formation of nitrogen-fixing root nodules. Amongst critical signals regulating this developmental process are bacterial Nod Factors (NFs) and several plant hormones, including cytokinins (CKs) and gibberellins (GAs). Here we show in Medicago truncatula that GA signaling mediated by DELLA1 decreases the amount of bioactive CKs in roots and negatively impacts the CRE1 (Cytokinin Response 1)-dependent NF activation of a subset of CK-signaling genes, as well as of the CK-regulated NSP2 (Nodulation Signaling pathway 2) and ERN1 (ERF required for Nodulation) early nodulation genes. Consistently, a dominant active DELLA1 protein can partially rescue the reduced nodulation of the cre1 mutant and triggers the formation of nodule-like structures when expressed in the root cortex or in the root epidermis. This suggests a model where the DELLA1-mediated GA signaling interplays with the CRE1-dependent CK pathway to regulate early nodulation in response to both NF and CK signals critical for this symbiotic interaction.

原文链接：

http://www.plantphysiol.org/content/early/2017/10/18/pp.17.00919

6NEW PHYTOLOGIST：美国科学院院士陈雪梅发表植物microRNA综述

Abstract

MicroRNAs (miRNAs) are small non-coding RNAs, of typically 20–24 nt, that regulate gene expression post-transcriptionally through sequence complementarity. Since the identification of the first miRNA, lin-4, in the nematode Caenorhabditis elegans in 1993, thousands of miRNAs have been discovered in animals and plants, and their regulatory roles in numerous biological processes have been uncovered. In plants, research efforts have established the major molecular framework of miRNA biogenesis and modes of action, and are beginning to elucidate the mechanisms of miRNA degradation. Studies have implicated restricted and surprising subcellular locations in which miRNA biogenesis or activity takes place. In this article, we summarize the current knowledge on how plant miRNAs are made and degraded, and how they repress target gene expression. We discuss not only the players involved in these processes, but also the subcellular sites in which these processes are known or implicated to take place. We hope to raise awareness that the cell biology of miRNAs holds the key to a full understanding of these enigmatic molecules.

原文链接：

http://onlinelibrary.wiley.com/doi/10.1111/nph.14834/full

7Plant Biotech J：中科院热带农业科学院（海口）Jin等人揭示MuMADS1和MaOFP1调节番茄卵裂突变体的水果质量

Abstract

Fruit ripening and quality are common botanical phenomena that are closely linked and strictly regulated by transcription factors. It was previously discovered that a banana MADS-box protein named MuMADS1 interacted with an ovate family protein named MaOFP1 to regulate banana fruit ripening. In order to further investigate the role of MuMADS1 and MaOFP1 in the regulation of fruit quality, a combination of genetic transformation and transcriptional characterization was used. The results indicated that the co-expression of MuMADS1 and MaOFP1 in the ovate mutant could compensate for fruit shape and inferior qualities relating to fruit firmness, soluble solids and sugar content. The number of differentially expressed genes (DEGs) was 1,395 in WT vs. ovate, with 883 up-regulated and 512 down-regulated genes, while the numbers of DEGs gradually decreased with the transformation of  MuMADS1  and  MaOFP1 into ovate. “Starch and sucrose metabolism” constituted the primary metabolic pathway, and the gene numbers in this pathway were obviously different when MuMADS1 and MaOFP1 were integrated into ovate. A series of metabolic genes involved in cell wall biosynthesis were up-regulated in the WT vs. ovate, which probably resulted in the firmer texture and lower sugar contents in the  ovate  fruit. These results demonstrate that  MuMADS1  and MaOFP1 are co-regulators of fruit quality, facilitating the dissection of the molecular mechanisms underlying fruit quality formation.

原文链接：

http://onlinelibrary.wiley.com/doi/10.1111/pbi.12843/full

8Plant Cell &Environ：浙江大学喻景权等人揭示番茄CRY1a在调控水果中的植物激素体内平衡，植物发育和类胡萝卜素代谢中起关键作用

Abstract

Blue light photoreceptors, cryptochromes (CRYs), regulate multiple aspects of plant growth and development. However, our knowledge of CRYs is predominantly based on model plant Arabidopsis at early growth stage. In this study, we elucidated funct 48 31895 48 15287 0 0 2874 0 0:00:11 0:00:05 0:00:06 2977ions of CRY1a gene in mature tomato (Solanum lycopersicum) plants by using cry1a mutants and CRY1a overexpressing lines (OE-CRY1a-1 and OE-CRY1a-2). In comparison with wild-type plants, cry1a mutants are relatively tall, accumulate low biomass and bear more fruits, whereas OE-CRY1aplants are short stature, and they not only flower lately but also bear less fruits. RNA-seq, qRT-PCR and LC-MS/MS analysis revealed that biosynthesis of gibberellin, cytokinin and jasmonic acid was down-regulated by CRY1a. Furthermore, DNA replication was drastically inhibited in leaves of OE-CRY1a lines, but promoted in cry1a mutants with concomitant changes in the expression of cell cycle genes. However, CRY1a positively regulated levels of soluble sugars, phytofluene, phytoene, lycopene and ß-carotene in the fruits. The results indicate the important role of CRY1a in plant growth and have implications for molecular interventions of CRY1a aimed at improving agronomic traits.

原文链接：

http://onlinelibrary.wiley.com/doi/10.1111/pce.13092/full

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