Bacterial diversity and composition on the rinds of specific melon cultivars and hybrids from across different growing regions in the United States.

The goal of this study was to characterize the bacterial diversity on different melon varieties grown in different regions of the US, and determine the influence that region, rind netting, and variety of melon has on the composition of the melon microbiome. Assessing the bacterial diversity of the microbiome on the melon rind can identify antagonistic and protagonistic bacteria for foodborne pathogens and spoilage organisms to improve melon safety, prolong shelf-life, and/or improve overall plant health. Bacterial community composition of melons (n = 603) grown in seven locations over a four-year period were used for 16S rRNA gene amplicon sequencing and analysis to identify bacterial diversity and constituents. Statistically significant differences in alpha diversity based on the rind netting and growing region (p < 0.01) were found among the melon samples. Principal Coordinate Analysis based on the Bray-Curtis dissimilarity distance matrix found that the melon bacterial communities clustered more by region rather than melon variety (R2 value: 0.09 & R2 value: 0.02 respectively). Taxonomic profiling among the growing regions found Enterobacteriaceae, Bacillaceae, Microbacteriaceae, and Pseudomonadaceae present on the different melon rinds at an abundance of ≥ 0.1%, but no specific core microbiome was found for netted melons. However, a core of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae were found for non-netted melons. The results of this study indicate that bacterial diversity is driven more by the region that the melons were grown in compared to rind netting or melon type. Establishing the foundation for regional differences could improve melon safety, shelf-life, and quality as well as the consumers' health.

Structured 3' UTRs destabilize mRNAs in plants.

BACKGROUND: RNA secondary structure (RSS) can influence the regulation of transcription, RNA processing, and protein synthesis, among other processes. 3' untranslated regions (3' UTRs) of mRNA also hold the key for many aspects of gene regulation. However, there are often contradictory results regarding the roles of RSS in 3' UTRs in gene expression in different organisms and/or contexts. RESULTS: Here, we incidentally observe that the primary substrate of miR159a (pri-miR159a), when embedded in a 3' UTR, could promote mRNA accumulation. The enhanced expression is attributed to the earlier polyadenylation of the transcript within the hybrid pri-miR159a-3' UTR and, resultantly, a poorly structured 3' UTR. RNA decay assays indicate that poorly structured 3' UTRs could promote mRNA stability, whereas highly structured 3' UTRs destabilize mRNA in vivo. Genome-wide DMS-MaPseq also reveals the prevailing inverse relationship between 3' UTRs' RSS and transcript accumulation in the transcriptomes of Arabidopsis, rice, and even human. Mechanistically, transcripts with highly structured 3' UTRs are preferentially degraded by 3'-5' exoribonuclease SOV and 5'-3' exoribonuclease XRN4, leading to decreased expression in Arabidopsis. Finally, we engineer different structured 3' UTRs to an endogenous FT gene and alter the FT-regulated flowering time in Arabidopsis. CONCLUSIONS: We conclude that highly structured 3' UTRs typically cause reduced accumulation of the harbored transcripts in Arabidopsis. This pattern extends to rice and even mammals. Furthermore, our study provides a new strategy of engineering the 3' UTRs' RSS to modify plant traits in agricultural production and mRNA stability in biotechnology.

Maize OPR2 and LOX10 Mediate Defense against Fall Armyworm and Western Corn Rootworm by Tissue-Specific Regulation of Jasmonic Acid and Ketol Metabolism.

Foliage-feeding fall armyworm (FAW; Spodoptera frugiperda) and root-feeding western corn rootworm (WCR; Diabrotica virgifera virgifera) are maize (Zea mays L.) pests that cause significant yield losses. Jasmonic acid (JA) plays a pivotal defense role against insects. 12-oxo-phytodienoic acid (12-OPDA) is converted into JA by peroxisome-localized OPDA reductases (OPR). However, little is known about the physiological functions of cytoplasmic OPRs. Here, we show that disruption of ZmOPR2 reduced wound-induced JA production and defense against FAW while accumulating more JA catabolites. Overexpression of ZmOPR2 in Arabidopsis enhanced JA production and defense against beet armyworm (BAW; Spodoptera exigua). In addition, lox10opr2 double mutants were more susceptible than either single mutant, suggesting that ZmOPR2 and ZmLOX10 uniquely and additively contributed to defense. In contrast to the defensive roles of ZmOPR2 and ZmLOX10 in leaves, single mutants did not display any alteration in root herbivory defense against WCR. Feeding on lox10opr2 double mutants resulted in increased WCR mortality associated with greater herbivory-induced production of insecticidal death acids and ketols. Thus, ZmOPR2 and ZmLOX10 cooperatively inhibit the synthesis of these metabolites during herbivory by WCR. We conclude that ZmOPR2 and ZmLOX10 regulate JA-mediated resistance in leaves against FAW while suppressing insecticidal oxylipin synthesis in roots during WCR infestation.

Arabidopsis RNA polymerase II C-terminal domain phosphatase-like 1 targets mitogen-activated protein kinase cascades to suppress plant immunity.

Mitogen-activated protein kinase (MAPK) cascades play pivotal roles in plant defense against phytopathogens downstream of immune receptor complexes. The amplitude and duration of MAPK activation must be strictly controlled, but the underlying mechanism remains unclear. Here, we identified Arabidopsis CPL1 (C-terminal domain phosphatase-like 1) as a negative regulator of microbe-associated molecular pattern (MAMP)-triggered immunity via a forward-genetic screen. Disruption of CPL1 significantly enhanced plant resistance to Pseudomonas pathogens induced by the bacterial peptide flg22. Furthermore, flg22-induced MPK3/MPK4/MPK6 phosphorylation was dramatically elevated in cpl1 mutants but severely impaired in CPL1 overexpression lines, suggesting that CPL1 might interfere with flg22-induced MAPK activation. Indeed, CPL1 directly interacted with MPK3 and MPK6, as well as the upstream MKK4 and MKK5. A firefly luciferase-based complementation assay indicated that the interaction between MKK4/MKK5 and MPK3/MPK6 was significantly reduced in the presence of CPL1. These results suggest that CPL1 plays a novel regulatory role in suppressing MAMP-induced MAPK cascade activation and MAMP-triggered immunity to bacterial pathogens.

9,10-KODA, an α-ketol produced by the tonoplast-localized 9-lipoxygenase ZmLOX5, plays a signaling role in maize defense against insect herbivory.

13-Lipoxygenases (LOXs) initiate the synthesis of jasmonic acid (JA), the best-understood oxylipin hormone in herbivory defense. However, the roles of 9-LOX-derived oxylipins in insect resistance remain unclear. Here, we report a novel anti-herbivory mechanism mediated by a tonoplast-localized 9-LOX, ZmLOX5, and its linolenic acid-derived product, 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (9,10-KODA). Transposon-insertional disruption of ZmLOX5 resulted in the loss of resistance to insect herbivory. lox5 knockout mutants displayed greatly reduced wound-induced accumulation of multiple oxylipins and defense metabolites, including benzoxazinoids, abscisic acid (ABA), and JA-isoleucine (JA-Ile). However, exogenous JA-Ile failed to rescue insect defense in lox5 mutants, while applications of 1 µM 9,10-KODA or the JA precursor, 12-oxo-phytodienoic acid (12-OPDA), restored wild-type resistance levels. Metabolite profiling revealed that exogenous 9,10-KODA primed the plants for increased production of ABA and 12-OPDA, but not JA-Ile. While none of the 9-oxylipins were able to rescue JA-Ile induction, the lox5 mutant accumulated lower wound-induced levels of Ca2+, suggesting this as a potential explanation for lower wound-induced JA. Seedlings pretreated with 9,10-KODA exhibited rapid or more robust wound-induced defense gene expression. In addition, an artificial diet supplemented with 9,10-KODA arrested fall armyworm larvae growth. Finally, analysis of single and double lox5 and lox10 mutants showed that ZmLOX5 also contributed to insect defense by modulating ZmLOX10-mediated green leaf volatile signaling. Collectively, our study uncovered a previously unknown anti-herbivore defense and hormone-like signaling activity for a major 9-oxylipin α-ketol.

The dicing activity of DCL3 and DCL4 is negatively affected by flavonoids.

KEY MESSAGE: The dicing activities of DCL3 and DCL4 are inhibited by accumulated metabolites in soybean leaves. Epicatechin and 7,4'-dihydroxyflavone inhibited Arabidopsis DCL3 and DCL4 in vitro. Flavonoids are major secondary metabolites in plants, and soybean (Glycine max L.) is a representative plant that accumulates flavonoids, including isoflavonoids, to high levels. Naturally-occurring RNA interference (RNAi) against the chalcone synthase (CHS) gene represses flavonoid (anthocyanin) biosynthesis in an organ-specific manner, resulting in a colorless (yellow) seed coat in many soybean cultivars. To better understand seed coat-specific naturally-occurring RNAi in soybean, we characterized soybean Dicer-like (DCL) 3 and 4, which play critical roles in RNAi. Using a previously established dicing assay, two dicing activities producing 24- and 21-nt siRNAs, corresponding to DCL3 and DCL4, respectively, were detected in soybean. Dicing activity was detected in colorless seed coats where RNAi against CHS genes was found, but no dicing activity was detected in leaves where CHS expression was prevalent. Biochemical analysis revealed that soybean leaves contained two types of inhibitors effective for Arabidopsis Dicers (AtDCL3 and AtDCL4), one of which was a heat-labile high molecular weight compound of 50 to 100 kD while another was a low molecular weight substance. We found that some flavonoids, such as epicatechin and 7,4'-dihydroxyflavone, inhibited both AtDCL3 and AtDCL4, but AtDCL4 was more sensitive to these flavonoids than AtDCL3. These results suggest that flavonoids inhibit the dicing activity of DCL4 and thereby attenuate RNAi in soybean leaves.

Overexpression of maize ZmLOX6 in Arabidopsis thaliana enhances damage-induced pentyl leaf volatile emissions that affect plant growth and interaction with aphids.

Pentyl leafy volatiles (PLV) are C5 volatiles produced from polyunsaturated fatty acids by plant 13-lipoxygenases (13-LOX) in concert with other lipid metabolizing enzymes. Unlike related C6 volatiles (GLV, green leafy volatiles), little is known about the biosynthesis and physiological function of PLV in plants. Zea mays LOX6 (ZmLOX6) is an unusual plant LOX that lacks lipid oxygenation activity but acts as a hydroperoxide lyase hypothesized to be specifically involved in PLV synthesis. We overexpressed ZmLOX6 in Arabidopsis thaliana and established that it indeed produces PLVs. Overexpression of ZmLOX6 caused a mild chlorotic phenotype, and induced a similar phenotype in untransformed Col-0 plants grown in close proximity, suggesting that airborne signals, such as PLVs, are responsible for the phenotype. PLV production, dependency on the substrate from endogenous 13-LOX(s), and likely competition with endogenous 13-oxylipin pathway were consistent with the model that ZmLOX6 functions as a hydroperoxide lyase. The abundance of individual PLVs was differentially affected by ZmLOX6 overexpression, and the new profile indicated that ZmLOX6 had reaction products distinct from endogenous PLV-producing activities in the Arabidopsis host plants. ZmLOX6 overexpression also induced a new hormonal status, which is likely responsible for increased attraction and propagation of aphids, nonetheless improving host plant tolerance to aphid infestation.

Production of Recombinant Active Human TGFß1 in Nicotiana benthamiana.

The production of recombinant proteins in plant systems is receiving wider attention. Indeed, various plant-produced pharmaceuticals have been shown to be biologically active. However, the production of human growth factors and cytokines in heterologous systems is still challenging because they often act as complex forms, such as homo- or hetero-dimers, and their production is tightly regulated in vivo. In this study, we demonstrated that the mature form of human TGFß1 produced and purified from Nicotiana benthamiana shows biological activity in animal cells. To produce the mature form of TGFß1, various recombinant genes containing the mature form of TGFß1 were generated and produced in N. benthamiana. Of these, a recombinant construct, BiP:M:CBM3:LAP[C33S]:EK:TGFß1, was expressed at a high level in N. benthamiana. Recombinant proteins were one-step purified using cellulose-binding module 3 (CBM3) as an affinity tag and microcrystalline cellulose (MCC) beads as a matrix. The TGFß1 recombinant protein bound on MCC beads was proteolytically processed with enterokinase to separate mature TGFß1. The mature TGFß1 still associated with Latency Associated Protein, [LAP(C33S)] that had been immobilized on MCC beads was released by HCl treatment. Purified TGFß1 activated TGFß1-mediated signaling in the A549 cell line, thereby inducing phosphorylation of SMAD-2, the expression of ZEB-2 and SNAIL1, and the formation of a filopodia-like structure. Based on these results, we propose that active mature TGFß1, one of the most challenging growth factors to produce in heterologous systems, can be produced from plants at a high degree of purity via a few steps.

Functional diversity of Medicago truncatula RNA polymerase II CTD phosphatase isoforms produced in the Arabidopsis thaliana superexpression platform.

Medicago truncatula is a model system for legume plants, which has substantially expanded the genome relative to the prototypical model dicot plant, Arabidopsis thaliana. An essential transcriptional regulator, FCP1 (transcription factor IIF-interacting RNA polymerase II carboxyl-terminal phosphatase 1) ortholog, is encoded by a single essential gene CPL4 (CTD-phosphatase-like 4), whereas M. truncatula genome contains four genes homologous to FCP1/AtCPL4, and splicing variants of MtCPL4 are observed. Functional diversification of MtCPL4 family proteins was analyzed using recombinant proteins (MtCPL4a1, MtCPL4a2, and MtCPL4b) produced in Arabidopsis cell culture system developed for plant protein overexpression. In vitro CTD phosphatase assay using highly purified MtCPL4 preparations revealed a potent CTD phosphatase activity in MtCPL4b, but not two splicing variants of MtCPL4a. On the other hand, in planta binding assay to RNA polymerase II (pol II) revealed a greater pol II-binding activity of both MtCPL4a variants. Our results indicate functional diversification of MtCPL4 isoforms and suggest the presence of a large number of functionally specialized CTD-phosphatase-like proteins in plants.

The Synthesis of Pentyl Leaf Volatiles and Their Role in Resistance to Anthracnose Leaf Blight.

Volatiles are important airborne chemical messengers that facilitate plant adaptation to a variety of environmental challenges. Lipoxygenases (LOXs) produce a bouquet of non-volatile and volatile oxylipins, including C6 green leaf volatiles (GLVs), which are involved in a litany of plant physiological processes. GLVs are emitted by a diverse array of plant species, and are the best-known group of LOX-derived volatiles. Five-carbon pentyl leaf volatiles (PLVs) represent another widely emitted group of LOX-derived volatiles that share structural similarity to GLVs, however, relatively little is known about their biosynthesis or biological activity. In this study, we utilized PLV-deficient mutants of maize and Arabidopsis and exogenous PLV applications to elucidate the biosynthetic order of individual PLVs. We further measured PLVs and GLVs after tissue disruption of leaves by two popular methods of volatile elicitation, wounding and freeze-thawing. Freeze-thawing distorted the volatile metabolism of both GLVs and PLVs relative to wounding, though this distortion differed between the two groups of volatiles. These results suggest that despite the structural similarity of these two volatile groups, they are differentially metabolized. Collectively, these results have allowed us to produce the most robust PLV pathway to date. To better elucidate the biological activity of PLVs, we show that PLVs induce maize resistance to the anthracnose pathogen, Colletotrichum graminicola, the effect opposite to that conferred by GLVs. Further analysis of PLV-treated and infected maize leaves revealed that PLV-mediated resistance is associated with early increases of oxylipin α- and γ-ketols, and later increases of oxylipin ketotrienes, hydroxytrienes, and trihydroxydienes. Ultimately, this study has produced the most up-to-date pathway for PLV synthesis, and reveals that PLVs can facilitate pathogen resistance through induction of select oxylipins.

The epigenetic factor FVE orchestrates cytoplasmic SGS3-DRB4-DCL4 activities to promote transgene silencing in Arabidopsis.

Posttranscriptional gene silencing (PTGS) is a regulatory mechanism to suppress undesired transcripts. Here, we identified Flowering locus VE (FVE), a well-known epigenetic component, as a new player in cytoplasmic PTGS. Loss-of-function fve mutations substantially reduced the accumulation of transgene-derived small interfering RNAs (siRNAs). FVE interacts with suppressor of gene silencing 3 (SGS3), a master component in PTGS. FVE promotes SGS3 homodimerization that is essential for its function. FVE can bind to single-stranded RNA and double-stranded RNA (dsRNA) with moderate affinities, while its truncated form FVE-8 has a significantly increased binding affinity to dsRNA. These affinities affect the association and channeling of SGS3-RNA to downstream dsRNA binding protein 4 (DRB4)/Dicer-like protein 2/4 (DCL2/4) complexes. Hence, FVE, but not FVE-8, biochemically enhances the DRB4/DCL2/4 activity in vitro. We surmise that FVE promotes production of transgene-derived siRNAs through concertedly tuning SGS3-DRB4/DCL2/4 functions. Thus, this study revealed a noncanonical role of FVE in PTGS.

Comparison of CD20 Binding Affinities of Rituximab Produced in Nicotiana benthamiana Leaves and Arabidopsis thaliana Callus.

Plants are promising drug-production platforms with high economic efficiency, stability, and convenience in mass production. However, studies comparing the equivalency between the original antibodies and those produced in plants are limited. Amino acid sequences that constitute the Fab region of an antibody are diverse, and the post-transcriptional modifications that occur according to these sequences in animals and plants are also highly variable. In this study, rituximab, a blockbuster antibody drug used in the treatment of non-Hodgkin's lymphoma, was produced in Nicotiana benthamiana leaves and Arabidopsis thaliana callus, and was compared to the original rituximab produced in CHO cells. Interestingly, the epitope recognition and antigen-binding abilities of rituximab from N. benthamiana leaves were almost lost. In the case of rituximab produced in A. thaliana callus, the specific binding ability and CD20 capping activity were maintained, but the binding affinity was less than 50% of that of original rituximab from CHO cells. These results suggest that different plant species exhibit different binding affinities. Accordingly, in addition to the differences in PTMs between mammals and plants, the differences between the species must also be considered in the process of producing antibodies in plants.

Imaging-Based Resistance Assay Using Enhanced Luminescence-Tagged Pseudomonas syringae Reveals a Complex Epigenetic Network in Plant Defense Signaling Pathways.

High-throughput resistance assays in plants have a limited selection of suitable pathogens. In this study, we developed a Pseudomonas syringae strain chromosomally tagged with the Nanoluc luciferase (NL) from the deep-sea shrimp Oplophorus gracilirostris, a bioluminescent marker significantly brighter than the conventional firefly luciferase. Our reporter strain tagged with NL was more than 100 times brighter than P. syringae tagged with the luxCDABE operon from Photorhabdus luminescens, one of the existing luciferase-based strains. In planta imaging was improved by using the surfactant Silwet L-77, particularly at a lower reporter concentration. Using this imaging system, more than 30 epigenetic mutants were analyzed for their resistance traits because the defense signaling pathway is known to be epigenetically regulated. SWC1, a defense-related chromatin remodeling complex, was found to be a positive defense regulator, which supported one of two earlier conflicting reports. Compromises in DNA methylation in the CG context led to enhanced resistance against virulent Pseudomonas syringae pv. tomato. Dicer-like and Argonaute proteins, important in the biogenesis and exerting the effector function of small RNAs, respectively, showed modest but distinct requirements for effector-triggered immunity and basal resistance to P. syringae pv. tomato. In addition, the transcriptional expression of an epigenetic component was found to be a significant predictor of its immunity contribution. In summary, this study showcased how a high-throughput resistance assay enabled by a pathogen strain with an improved luminescent reporter could provide insightful knowledge about complex defense signaling pathways.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Transition of aromatic volatile and transcriptome profiles during melon fruit ripening.

Melon (Cucumis melo L.) is an important diploid crop with a wide variety of flavors due to its distinct aromatic volatile organic compounds (VOC). To understand the development of VOC profiles during fruit development, we performed metabolomic and transcriptomic analysis of two cantaloupe varieties over the course of fruit development. A total of 130 metabolites were detected in fruit samples, and 449014207 reads were mapped to the melon genome. A total of 4469 differentially expressed genes in fruits were identified and used to visualize the transition of VOC and transcriptomic profiles during the fruit development. A shift of VOC profiles in both varieties was observed from early-fruit profiles enriched in C5-C8 lipid-derived VOCs to late-fruit profiles abundant in C9 lipid-derived VOCs, apocarotenoids, and esters. The shift coincided with the expression of specific isoforms of lipid and carotenoid metabolizing enzymes as well as transcription factors involved in fruit ripening, metabolite regulation, and hormone signaling.

Frequent asymptomatic infection with tobacco ringspot virus on melon fruit.

Melon is one of the most popular fruits worldwide and has been bred into various cultivars. RNA-sequencing using healthy melon fruit was performed to determine differences in gene expression among cultivars. Unexpected RNA-seq results revealed that viruses asymptomatically infected fruits at a high frequency (16 of 21 fruits examined were infected) and that viral transcripts highly accumulated in comparison with host transcripts (15 %-75 % of total reads). Their nucleotide sequences and phylogenetic analyses indicated that more than 10 novel isolates of tobacco ringspot virus (TRSV) were found in melon fruits. Asymptomatic infection with TRSV on melon fruits was confirmed by both immunoblot and RT-PCR analyses. Numerous isolates of TRSV generated and maintained in melon fields, and this is likely due to their asymptomatic infections. This TRSV melon isolate infected Nicotiana benthamiana plants with stunting and yellowing symptoms. This is the first report of frequent and asymptomatic infection of TRSV in consumable melon fruits.

Biochemical characterization of the dicing activity of Dicer-like 2 in the model filamentous fungus Neurospora crassa.

Dicing of double-stranded RNA (dsRNA) into small RNA is an essential process to trigger transcriptional and post-transcriptional gene silencing. Using cell-free extracts of the model filamentous fungus Neurospora crassa, we successfully detected the dicing activity of one of two N. crassa Dicers NcDCL2. The predominant 23-nucleotide (nt) cleavage product was always detected from 30-nt to 130-nt dsRNA substrates, and additional products of approximately 18 to 28 nt were occasionally produced. The enzymatic properties of NcDCL2 are different from those of insect and plant small interfering RNA (siRNA)-producing Dicers, Drosophila melanogaster Dicer-2 and Arabidopsis thaliana DCL3 and DCL4 (AtDCL3 and AtDCL4). Whereas AtDCL3 and AtDCL4 preferentially cleave short and long dsRNAs, respectively, NcDCL2 cleaved both short and long dsRNAs. These results suggest that N. crassa has a single siRNA-producing Dicer NcDCL2, which is a prototype of plant siRNA-producing Dicers with distinct functions in diverse RNA silencing pathways. The dicing assay reported here is convenient to detect and biochemically characterize the dicing activities of both plant and fungal Dicers, and is likely applicable to other organisms.

Degradation of SERRATE via ubiquitin-independent 20S proteasome to survey RNA metabolism.

SERRATE (SE) is a key factor in RNA metabolism. Here, we report that SE binds 20S core proteasome α subunit G1 (PAG1) among other components and is accumulated in their mutants. Purified PAG1-containing 20S proteasome degrades recombinant SE via an ATP- and ubiquitin-independent manner in vitro. Nevertheless, PAG1 is a positive regulator for SE in vivo, as pag1 shows comparable molecular and/or developmental defects relative to se. Furthermore, SE is poorly assembled into macromolecular complexes, exemplified by the microprocessor in pag1 compared with Col-0. SE overexpression triggered the destruction of both transgenic and endogenous protein, leading to similar phenotypes of se and SE overexpression lines. We therefore propose that PAG1 degrades the intrinsically disordered portion of SE to secure the functionality of folded SE that is assembled and protected in macromolecular complexes. This study provides insight into how the 20S proteasome regulates RNA metabolism through controlling its key factor in eukaryotes.

Development of core-collections for Guizhou tea genetic resources and GWAS of leaf size using SNP developed by genotyping-by-sequencing.

An accurate depiction of the genetic relationship, the development of core collection, and genome-wide association analysis (GWAS) are key for the effective exploitation and utilization of genetic resources. Here, genotyping-by-sequencing (GBS) was used to characterize 415 tea accessions mostly collected from the Guizhou region in China. A total of 30,282 high-quality SNPs was used to estimate the genetic relationships, develop core collections, and perform GWAS. We suggest 198 and 148 accessions to represent the core set and mini-core set, which consist of 47% and 37% of the whole collection, respectively, and contain 93-95% of the total SNPs. Furthermore, the frequencies of all alleles and genotypes in the whole set were very well retained in the core set and mini-core set. The 415 accessions were clustered into 14 groups and the core and the mini-core collections contain accessions from each group, species, cultivation status and growth habit. By analyzing the significant SNP markers associated with multiple traits, nine SNPs were found to be significantly associated with four leaf size traits, namely MLL, MLW, MLA and MLSI (P < 1.655E-06). This study characterized the genetic distance and relationship of tea collections, suggested the core collections, and established an efficient GWAS analysis of GBS result.

Lack of endoplasmic reticulum quality control (ERQC) promotes tonoplast (TP) targeting of KORRIGAN 1 (KOR1).

Cellular dynamics of KORRIGAN 1 (KOR1) is closely linked with cellulose biosynthesis and plant osmotic stress tolerance. Cycling of KOR1 between the plasma membrane (PM) and trans-Golgi Network (TGN) is maintained by sequence motifs and protein structures that are recognized by cellular transport and quality control mechanisms. Several mutations in KOR1, as well as in the host genetic background, promote the mistargeting of KOR1 and induce KOR1 accumulation in the tonoplast (TP). Yet, little is known about how retention and sorting of KOR1 are regulated in the PM-TGN cycle. Forward genetic screening for GFP-KOR1 mislocalizing phenotype resulted in several mutant lines with different localization patterns or signal intensity of GFP-KOR1. One of the identified mutants were disrupted at UDP-glucose:glycoprotein glucosyltransferase (UGGT) locus, which is essential for the protein quality control in the ER. Our finding suggests the mis/unfolded structure of KOR1 triggers the TP targeting.