A plant Bcl-2-associated athanogene is proteolytically activated to confer fungal resistance

A Mitochondrial Localized Chaperone Regulator OsBAG6 Functions in Saline-Alkaline Stress Tolerance in Rice

B-cell lymphoma 2 (Bcl-2)-associated athanogene (BAG) family genes play prominent roles in regulating plant growth, development, and stress response. Although the molecular mechanism underlying BAG's response to abiotic stress has been studied in Arabidopsis, the function of OsBAG underlying saline-alkaline stress tolerance in rice remains unclear. In this study, OsBAG6, a chaperone regulator localized to mitochondria, was identified as a novel negative regulator of saline-alkaline stress tolerance in rice. The expression level of OsBAG6 was induced by high concentration of salt, high pH, heat and abscisic acid treatments. Overexpression of OsBAG6 in rice resulted in significantly reduced plant heights, grain size, grain weight, as well as higher sensitivity to saline-alkaline stress. By contrast, the osbag6 loss-of-function mutants exhibited decreased sensitivity to saline-alkaline stress. The transcriptomic analysis uncovered differentially expressed genes related to the function of "response to oxidative stress", "defense response", and "secondary metabolite biosynthetic process" in the shoots and roots of OsBAG6-overexpressing transgenic lines. Furthermore, cytoplasmic levels of Ca2+ increase rapidly in plants exposed to saline-alkaline stress. OsBAG6 bound to calcium sensor OsCaM1-1 under normal conditions, which was identified by comparative interactomics, but not in the presence of elevated Ca2+. Released OsCaM1-1 saturated with Ca2+ is then able to regulate downstream stress-responsive genes as part of the response to saline-alkaline stress. OsBAG6 also interacted with energy biosynthesis and metabolic pathway proteins that are involved in plant growth and saline-alkaline stress response mechanisms. This study reveals a novel function for mitochondrial localized OsBAG6 proteins in the saline-alkaline stress response alongside OsCaM1-1.

BAG8 positively regulates cold stress tolerance by modulating photosystem, antioxidant system and protein protection in Solanum lycopersicum

The B-cell lymphoma 2 (Bcl-2)-associated athanogene (BAG) family is a relatively conserved and multifunctional co-chaperones in animals and plants, which can flexibly interact with a variety of proteins and regulate various processes from growth and development to stress response. However, compared with animals, the function of BAG family in plant remains largely unknown, especially in response to cold stress. In this study, we have found that the expression of BAG8 was significantly induced in tomato under cold stress. Results showed that bag8 mutants exhibit significantly reduced tolerance towards cold stress, while BAG8 overexpressing lines were relatively resistant as reflected by the phenotype and membrane peroxidation. Measuring of gas exchange parameters, photosystem I (PSI) and photosystem II (PSII) of tomato leaves under cold stress further revealed that BAG8 mitigated cold-induced damage in photosynthetic system. Additionally, bag8 mutants exhibited more cold-induced reactive oxygen species, which were substantially normalized in BAG8 overexpressing plants. Nevertheless, the activities of antioxidant enzymes which were compromised in bag8 mutants were improved in BAG8 overexpressing plants facing cold stress. Additionally, BAG8 interacted with heat shock protein Hsp70 and protein phosphatase PP2A both in vitro and in vivo. Our results demonstrate that BAG8 plays a positive role in cold tolerance in tomato probably by the improvement of photosystems and antioxidant systems, and by interacting with Hsp70 involved in photosynthesis and PP2A involved in stomatal development.

The oomycete-specific BAG subfamily maintains protein homeostasis and promotes pathogenicity in an atypical HSP70-independent manner

Protein homeostasis is vital for organisms and requires chaperones like the conserved Bcl-2-associated athanogene (BAG) co-chaperones that bind to the heat shock protein 70 (HSP70) through their C-terminal BAG domain (BD). Here, we show an unconventional BAG subfamily exclusively found in oomycetes. Oomycete BAGs feature an atypical N-terminal BD with a short and oomycete-specific α1 helix (α1'), plus a C-terminal small heat shock protein (sHSP) domain. In oomycete pathogen Phytophthora sojae, both BD-α1' and sHSP domains are required for P. sojae BAG (PsBAG) function in cyst germination, pathogenicity, and unfolded protein response assisting in 26S proteasome-mediated degradation of misfolded proteins. PsBAGs form homo- and heterodimers through their unique BD-α1' to function properly, with no recruitment of HSP70s to form the common BAG-HSP70 complex found in other eukaryotes. Our study highlights an oomycete-exclusive protein homeostasis mechanism mediated by atypical BAGs, which provides a potential target for oomycete disease control.

Tomato chlorosis virus p22 interacts with NbBAG5 to inhibit autophagy and regulate virus infection

Tomato chlorosis virus (ToCV) is a member of the genus Crinivirus in the family Closteroviridae. It has a wide host range and wide distribution, causing serious harm to the vegetable industry. The autophagy pathway plays an important role in plant resistance to virus infection. Viruses and plant hosts coevolve in defence and antidefence processes around autophagy. In this study, the interaction between ToCV p22 and Nicotiana benthamiana B-cell lymphoma2-associated athanogenes5 Nicotiana benthamiana (NbBAG5) was examined. Through overexpression and down-regulation of NbBAG5, results showed that NbBAG5 could negatively regulate ToCV infection. NbBAG5 was found to be localized in mitochondria and can change the original localization of ToCV p22, which is colocalized in mitochondria. NbBAG5 inhibited the expression of mitophagy-related genes and the number of autophagosomes, thereby regulating viral infection by affecting mitophagy. In summary, this study demonstrated that ToCV p22 affects autophagy by interacting with NbBAG5, established the association between viral infection, BAG proteins family, and the autophagy pathway, and explained the molecular mechanism by which ToCV p22 interacts with NbBAG5 to inhibit autophagy to regulate viral infection.

BAG6-A from Fragaria viridis pollen modulates gametophyte development in diploid strawberry

Male and female gametophyte development processes are essential steps in the life cycles of all land plants. Here, we characterized a gene, FviBAG6-A, screened from the Fragaria viridis (2 n = 2x=14) pollen cDNA library and physically interacted with S-RNase. Ubiquitinated of S_a-RNase might be determined by the interaction of FviBAG6-A in the ubiquitin-proteasome system during fertilization. We found that overexpression of FviBAG6-A in Arabidopsis caused shorter silique length, and decreased silique number. Moreover, overexpression of FviBAG6-A in Fragaria vesca (2 n = 2x=14) led to a greatly reduced seed number, with nearly 80% of the seeds aborted. Analyses of paraffin sections and reactive oxygen species (ROS) content revealed that the majority of severe pollen defects were likely due to the early degradation of the tapetum and middle layer as a result of ROS accumulation and abnormal development of the uninucleate megaspore mother. Moreover, the FviBAG6-A interact with the E3 ligase SIZ1 and contribute to the SUMOylation of FviBAG6-A , which may be induced by the high level of ROS content, further promoting gametophyte abortion in strawberry transgenic lines. This study characterized the FviBAG6-A and reveals its novel function in gametophyte development.

Functional insights of plant bcl-2-associated ahanogene (BAG) proteins: Multi-taskers in diverse cellular signal transduction pathways

Bcl-2-associated athanogene (BAG) gene family is a highly conserved molecular chaperone cofactor in evolution from yeast to humans and plants playing important roles in a variety of signal pathways. Plant BAG proteins have special structures, especially those containing CaM-binding IQ motifs which are unique to plants. While early studies focused more on the structure and physiological function of plant BAGs, recent studies have revealed many novel functional mechanisms involved in multiple cellular processes. How to achieve signal specificity has become an interesting topic of plant BAG research. In this review, we have provided a historic view of plant BAG research and summarized recent advances in the establishment of BAG as essential components in normal plant growth, environmental stress response, and plant immunity. Based on the relationship between BAG proteins and their newly interacting proteins, this review highlights the functional mechanisms of various cellular signals mediated by plant BAGs. Future work needs to focus on the post-translational modification of BAG proteins, and on understanding how specificity is achieved among BAG signaling pathways.

The Bcl-2-associated athanogene gene family in tobacco (Nicotiana tabacum) and the function of NtBAG5 in leaf senescence

Leaf senescence in tobacco is closely related to leaf maturation and secondary metabolites. Bcl-2-associated athanogene (BAG) family members are highly conserved proteins and play key roles in senescence, growth and development, and resistance to biotic and abiotic stresses. Herein, the BAG family of tobacco was identified and characterized. In total, 19 tobacco BAG protein candidate genes were identified and divided into two classes, class I comprising NtBAG1a-e, NtBAG3a-b, and NtBAG4a-c and class II including NtBAG5a-e, NtBAG6a-b, and NtBAG7. Genes in the same subfamily or branch of the phylogenetic tree exhibited similarities in gene structure and the cis-element on promoters. RNA-seq and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) revealed that the expression of NtBAG5c-f and NtBAG6a-b was upregulated in senescent leaves, implying that they play a role in regulating leaf senescence. NtBAG5c was localized in the nucleus and cell wall as a homology of leaf senescence related gene AtBAG5. Further, the interaction of NtBAG5c with heat-shock protein 70 (HSP70) and sHSP20 was demonstrated using yeast two-hybrid experiment. Virus-induced gene silencing indicated that NtBAG5c reduced the lignin content and increased superoxide dismutase (SOD) activity and hydrogen peroxide (H₂O₂) accumulation. In NtBAG5c-silenced plants, the expression of multiple senescence-related genes cysteine proteinase (NtCP1), SENESCENCE 4 (SEN4) and SENESCENCE-ASSOCIATED GENE 12 (SAG12) was downregulated. In conclusion, tobacco BAG protein candidate genes were identified and characterized for the first time.

Genome-Wide Identification of the Bcl-2 Associated Athanogene (BAG) Gene Family in Solanum lycopersicum and the Functional Role of SlBAG9 in Response to Osmotic Stress

The Bcl-2-associated athanogene (BAG) proteins are a family of multi-functional group of co-chaperones regulators, modulating diverse processes from plant growth and development to stress response. Here, 10 members of SlBAG gene family were identified based on the available tomato (Solanum lycopersicum) genomic information and named as SlBAG1-10 according to their chromosomal location. All SlBAG proteins harbor a characteristic BAG domain, categorized into two groups, and SlBAG4, SlBAG7, and SlBAG9 of group I contain a plant-specific isoleucine glutamine (IQ) calmodulin-binding motif located in the N terminus. The quantitative real-time PCR expression analysis revealed that these SlBAG genes had organ-specific expression patterns and most SlBAG genes were differentially expressed in multiple abiotic stresses including drought, salt, high temperature, cold, and cadmium stress as well as abscisic acid and H₂O₂. In addition, heterologous overexpression of SlBAG9 increased the sensitivity of Arabidopsis to drought, salt, and ABA during seed germination and seedling growth. The decreased tolerance may be due to the downregulation of stress-related genes expression and severe oxidative stress. The expression levels of some stress and ABA-related genes, such as ABI3, RD29A, DREB2A, and P5CS1, were significantly inhibited by SlBAG9 overexpression under osmotic stress. Meanwhile, the overexpression of SlBAG9 inhibited the expression of FSD1 and CAT1 under stress conditions and the decreased levels of superoxide dismutase and catalase enzyme activities were detected accompanying the trends in the expression of both genes, which resulted in H₂O₂ accumulation and lipid peroxidation. Taken together, these findings lay a foundation for the future study of the biological function of SlBAG genes in tomato.

Grapevine DMR6-1 Is a Candidate Gene for Susceptibility to Downy mildew

Grapevine (Vitis vinifera) is a valuable crop in Europe for both economical and cultural reasons, but highly susceptible to Downy mildew (DM). The generation of resistant vines is of critical importance for a sustainable viticulture and can be achieved either by introgression of resistance genes in susceptible varieties or by mutation of Susceptibility (S) genes, e.g., by gene editing. This second approach offers several advantages: it maintains the genetic identity of cultivars otherwise disrupted by crossing and generally results in a broad-spectrum and durable resistance, but it is hindered by the poor knowledge about S genes in grapevines. Candidate S genes are Downy mildew Resistance 6 (DMR6) and DMR6-Like Oxygenases (DLOs), whose mutations confer resistance to DM in Arabidopsis. In this work, we show that grapevine VviDMR6-1 complements the Arabidopsis dmr6-1 resistant mutant. We studied the expression of grapevine VviDMR6 and VviDLO genes in different organs and in response to the DM causative agent Plasmopara viticola. Through an automated evaluation of causal relationships among genes, we show that VviDMR6-1, VviDMR6-2, and VviDLO1 group into different co-regulatory networks, suggesting distinct functions, and that mostly VviDMR6-1 is connected with pathogenesis-responsive genes. Therefore, VviDMR6-1 represents a good candidate to produce resistant cultivars with a gene-editing approach.

Unraveling the role of tomato Bcl-2-associated athanogene (BAG) proteins during abiotic stress response and fruit ripening

B-cell lymphoma2 (Bcl-2)-associated athanogene (BAG) family proteins are evolutionary conserved across all eukaryotes. These proteins interact with HSP70/HSC70 and function as co-chaperones during stress response and developmental pathways. Compared to the animal counterpart, the BAG proteins in plants are much less studied and primarily Arabidopsis BAG proteins have been identified and characterized for their role in programmed cell death, homeostasis, growth and development, abiotic and biotic stress response. Here, we have identified BAG protein family (SlBAGs) in tomato, an economically important and a model fruit crop using genome-wide scanning. We have performed phylogenetic analysis, genes architecture assessment, chromosomal location and in silico promoter analysis. Our data suggest that SlBAGs show differential tissue specific expression pattern during plant development particularly fruit development and ripening. Furthermore, we reported that expression of SlBAGs is modulated during abiotic stresses and is regulated by stress hormones ABA and ethylene. In planta subcellular localization reveals their diverse subcellular localization, and many members are localized in nucleus and cytoplasm. Like previous reports, our protein-protein interaction network and yeast two-hybrid analysis uncover that SlBAGs interact with HSP70. The current study provides insights into role of SlBAGs in plant development particualry fruit ripening and abiotic stress response.

The core autophagy machinery is not required for chloroplast singlet oxygen-mediated cell death in the Arabidopsis thaliana plastid ferrochelatase two mutant

BACKGROUND

Chloroplasts respond to stress and changes in the environment by producing reactive oxygen species (ROS) that have specific signaling abilities. The ROS singlet oxygen (¹O₂) is unique in that it can signal to initiate cellular degradation including the selective degradation of damaged chloroplasts. This chloroplast quality control pathway can be monitored in the Arabidopsis thaliana mutant plastid ferrochelatase two (fc2) that conditionally accumulates chloroplast ¹O₂ under diurnal light cycling conditions leading to rapid chloroplast degradation and eventual cell death. The cellular machinery involved in such degradation, however, remains unknown. Recently, it was demonstrated that whole damaged chloroplasts can be transported to the central vacuole via a process requiring autophagosomes and core components of the autophagy machinery. The relationship between this process, referred to as chlorophagy, and the degradation of ¹O₂-stressed chloroplasts and cells has remained unexplored.

RESULTS

To further understand ¹O₂-induced cellular degradation and determine what role autophagy may play, the expression of autophagy-related genes was monitored in ¹O₂-stressed fc2 seedlings and found to be induced. Although autophagosomes were present in fc2 cells, they did not associate with chloroplasts during ¹O₂ stress. Mutations affecting the core autophagy machinery (atg5, atg7, and atg10) were unable to suppress ¹O₂-induced cell death or chloroplast protrusion into the central vacuole, suggesting autophagosome formation is dispensable for such ¹O₂-mediated cellular degradation. However, both atg5 and atg7 led to specific defects in chloroplast ultrastructure and photosynthetic efficiencies, suggesting core autophagy machinery is involved in protecting chloroplasts from photo-oxidative damage. Finally, genes predicted to be involved in microautophagy were shown to be induced in stressed fc2 seedlings, indicating a possible role for an alternate form of autophagy in the dismantling of ¹O₂-damaged chloroplasts.

CONCLUSIONS

Our results support the hypothesis that ¹O₂-dependent cell death is independent from autophagosome formation, canonical autophagy, and chlorophagy. Furthermore, autophagosome-independent microautophagy may be involved in degrading ¹O₂-damaged chloroplasts. At the same time, canonical autophagy may still play a role in protecting chloroplasts from ¹O₂-induced photo-oxidative stress. Together, this suggests chloroplast function and degradation is a complex process utilizing multiple autophagy and degradation machineries, possibly depending on the type of stress or damage incurred.

Plant Mitophagy in Comparison to Mammals: What Is Still Missing?

Mitochondrial homeostasis refers to the balance of mitochondrial number and quality in a cell. It is maintained by mitochondrial biogenesis, mitochondrial fusion/fission, and the clearance of unwanted/damaged mitochondria. Mitophagy represents a selective form of autophagy by sequestration of the potentially harmful mitochondrial materials into a double-membrane autophagosome, thus preventing the release of death inducers, which can trigger programmed cell death (PCD). Recent advances have also unveiled a close interconnection between mitophagy and mitochondrial dynamics, as well as PCD in both mammalian and plant cells. In this review, we will summarize and discuss recent findings on the interplay between mitophagy and mitochondrial dynamics, with a focus on the molecular evidence for mitophagy crosstalk with mitochondrial dynamics and PCD.

Centrality of BAGs in Plant PCD, Stress Responses, and Host Defense

Programmed cell death (PCD) is a genetically regulated process for the selective demise of unwanted and damaged cells. Although our understanding of plant PCD pathways has advanced significantly, doubts remain on the extent of conservation of animal apoptosis in plants. At least at the primary sequence level, plants do not encode the regulators of animal apoptosis. Structural analyses have enabled the identification of the B cell lymphoma 2 (Bcl-2)-associated athanogene (BAG) family of co-chaperones in plants. This discovery suggests that some aspects of animal PCD are conserved in plants, while the varied subcellular localization of plant BAGs indicates that they may have evolved distinct functions. Here we review plant BAG proteins, with an emphasis on their roles in the regulation of plant PCD.

Establishment and validation of a novel autophagy-related gene signature for patients with breast cancer

BACKGROUND

There exists considerable evidence conforming that autophagy may play an important role in the biological process of breast cancer. This study aimed to construct and evaluate a novel autophagy-related gene signature as a potential prognostic factor and therapeutic target in breast cancer patients based on high-throughput sequencing datasets.

MATERIALS & METHODS

Autophagy-related genes obtained from the Human Autophagy Database and high-sequencing data obtained from The Cancer Genome Atlas (TCGA) were analyzed to identify differential expressed genes (DEGs) between tumor and normal tissues. Then GO and KEGG analysis were performed to explore potential biological and pathological functions of DEGs. Autophagy-related prognostic genes were identified by univariate COX regression analysis. Subsequently stepwise model selection using the Alkaike information criterion (AIC) and multivariate COX regression model was performed to construct autophagy-related gene signature. Then patients were divided into high- and low-risk groups based on the risk score identified by the autophagy-related gene signature. Multivariate COX regression model and stratification analysis were used to specify the prognostic value of this gene signature in whole cohort and various subgroups. T-test and ANOVA analysis were used to compare the expression differences of continuous variables (5 prognostic genes and risk score) in binary and multiple category groups respectively. Kaplan-Meier analysis, log-rank tests and the area under receiver operating characteristic (ROC) curve (AUC) were conducted to validate the accuracy and precise of the autophagy-related gene signature based on GSE20685 and GSE21653 datasets.

RESULTS

We profiled autophagy-related DEGs in normal and breast tumor tissues. GO and KEGG analysis indicated that autophagy-related DEGs might participate in breast cancer occurrence, development and drug resistance. Then we identified five autophagy-related genes (EIF4EBP1, ATG4A, BAG1, MAP1LC3A and SERPINA1) that had significantly prognostic values for breast cancer. Autophagy-related gene signature was constructed and patients were divided into high- and low- risk groups based on their risk score. Patients in the high-risk group tended to have shorter overall survival (OS) and relapse-free survival (RFS) times than those in the low-risk group (OS: HR = 1.620, 95%CIs: 1.345-1.950; P < 0.001; RFS: HR = 1.487, 95%CIs: 1.248-1.771, P < 0.001). Autophagy-related gene signature had significant prognostic value in stratified subgroups especially in advanced breast cancer subgroups (T3-4; N2-3; stage III-IV). Its prognostic value was further confirmed in two GEO validation datasets (GSE20685: P = 6.795e-03; GSE21653: P = 1.383e-03). Finally, association analysis between clinicopathological factors and gene signature showed the risk score was higher in patients with ER/PR negative, higher clinical stage or T stage (P < 0.01).

CONCLUSION

We established and confirmed a novel autophagy-related gene signature for patients with breast cancer that had independent survival prognostic value especially in advanced breast cancer subgroups. Our research might promote the molecular mechanism study of autophagy-related genes in breast cancer.

BCL2-ASSOCIATED ATHANOGENE4 Regulates the KAT1 Potassium Channel and Controls Stomatal Movement

Potassium (K+) is a key monovalent cation necessary for multiple aspects of cell growth and survival. In plants, this cation also plays a key role in the control of stomatal movement. KAT1 and its homolog KAT2 are the main inward rectifying channels present in guard cells, mediating K+ influx into these cells, resulting in stomatal opening. To gain further insight into the regulation of these channels, we performed a split-ubiquitin protein-protein interaction screen searching for KAT1 interactors in Arabidopsis (Arabidopsis thaliana). We characterized one of these candidates, BCL2-ASSOCIATED ATHANOGENE4 (BAG4), in detail using biochemical and genetic approaches to confirm this interaction and its effect on KAT1 activity. We show that BAG4 improves KAT1-mediated K+ transport in two heterologous systems and provide evidence that in plants, BAG4 interacts with KAT1 and favors the arrival of KAT1 at the plasma membrane. Importantly, lines lacking or overexpressing the BAG4 gene show altered KAT1 plasma membrane accumulation and alterations in stomatal movement. Our data allowed us to identify a KAT1 regulator and define a potential target for the plant BAG family. The identification of physiologically relevant regulators of K+ channels will aid in the design of approaches that may impact drought tolerance and pathogen susceptibility.

Cytoprotective Co-chaperone BcBAG1 Is a Component for Fungal Development, Virulence, and Unfolded Protein Response (UPR) of Botrytis cinerea

The Bcl-2 associated athanogene (BAG) family is an evolutionarily conserved group of co-chaperones that confers stress protection against a variety of cellular insults extending from yeasts, plants to humans. Little is known, however, regarding the biological role of BAG proteins in phytopathogenic fungi. Here, we identified the unique BAG gene (BcBAG1) from the necrotrophic fungal pathogen, Botrytis cinerea. BcBAG1 is the homolog of Arabidopsis thaliana AtBAG4, and ectopic expression of BcBAG1 in atbag4 knock-out mutants restores salt tolerance. BcBAG1 deletion mutants (ΔBcbag1) exhibited decreased conidiation, enhanced melanin accumulation and lost the ability to develop sclerotia. Also, BcBAG1 disruption blocked fungal conidial germination and successful penetration, leading to a reduced virulence in host plants. BcBAG1 contains BAG (BD) domain at C-terminus and ubiquitin-like (UBL) domain at N-terminus. Complementation assays indicated that BD can largely restored pathogenicity of ΔBcbag1. Abiotic stress assays showed ΔBcbag1 was more sensitive than the wild-type strain to NaCl, calcofluor white, SDS, tunicamycin, dithiothreitol (DTT), heat and cold stress, suggesting BcBAG1 plays a cytoprotective role during salt stress, cell wall stress, and ER stress. BcBAG1 negatively regulated the expression of BcBIP1, BcIRE1 and the splicing of BcHAC1 mRNA, which are core regulators of unfolded protein response (UPR) during ER stress. Moreover, BcBAG1 interacted with HSP70-type chaperones, BcBIP1 and BcSKS2. In summary, this work demonstrates that BcBAG1 is pleiotropic and not only essential for fungal development, hyphal melanization, and virulence, but also required for response to multiple abiotic stresses and UPR pathway of B. cinerea.

The Roles of Ubiquitin-Binding Protein Shuttles in the Degradative Fate of Ubiquitinated Proteins in the Ubiquitin-Proteasome System and Autophagy

The ubiquitin-proteasome system (UPS) and autophagy are the two major intracellular protein quality control (PQC) pathways that are responsible for cellular proteostasis (homeostasis of the proteome) by ensuring the timely degradation of misfolded, damaged, and unwanted proteins. Ubiquitination serves as the degradation signal in both these systems, but substrates are precisely targeted to one or the other pathway. Determining how and when cells target specific proteins to these two alternative PQC pathways and control the crosstalk between them are topics of considerable interest. The ubiquitin (Ub) recognition code based on the type of Ub-linked chains on substrate proteins was believed to play a pivotal role in this process, but an increasing body of evidence indicates that the PQC pathway choice is also made based on other criteria. These include the oligomeric state of the Ub-binding protein shuttles, their conformation, protein modifications, and the presence of motifs that interact with ATG8/LC3/GABARAP (autophagy-related protein 8/microtubule-associated protein 1A/1B-light chain 3/GABA type A receptor-associated protein) protein family members. In this review, we summarize the current knowledge regarding the Ub recognition code that is bound by Ub-binding proteasomal and autophagic receptors. We also discuss how cells can modify substrate fate by modulating the structure, conformation, and physical properties of these receptors to affect their shuttling between both degradation pathways.

The expression and role of miR-181a in multiple myeloma

This study aims to investigate the role of miR-181a in multiple myeloma (MM). Fresh peripheral blood and bone marrows were collected. Expression of miR-181a, BCL-2 mRNA, and NOVA1 mRNA was detected by RT-qPCR. The correlation between miR-181a and clinical features of MM was further analyzed. miR-181a in serum and bone marrow mononuclear cells of MM patients were significantly higher. And, miR-181a level was significantly higher in MM Durie-Salmon stage III than that in stage I+II. miR-181a was positively correlated to Durie-Salmon staging, age, kidney injury, bone injury, β2-MG whereas negatively related to red blood cell, hemoglobin, and albumin. Additionally, BCL-2 and NOVA1 were predicted to be downstream targets of miR-181a. BCL-2 mRNA was significantly higher in the bone marrow mononuclear cells from MM patients. To sum up, the miR-181a expression is increased in peripheral blood and bone marrow of MM patients and is closely related to the clinical pathological indicators of MM.

Many Shades of Grey in Botrytis-Host Plant Interactions

The grey mould Botrytis cinerea causes disease in more than 1000 plant species, including important crops. The interaction between Botrytis and its (potential) hosts is determined by quantitative susceptibility and virulence traits in both interacting partners, resulting in a greyscale of disease outcomes. Fungal infection was long thought to rely mainly on its capacity to kill the host plant and degrade plant tissue. Recent research has revealed that Botrytis exploits two crucial biological processes in host plants for its own success. We highlight recent findings that illustrate that the interactions between Botrytis and its host plants are subtle and we discuss the molecular and cellular mechanisms controlling the many shades of grey during these interactions.

Molecular dissection of distinct symptoms induced by tomato chlorosis virus and tomato yellow leaf curl virus based on comparative transcriptome analysis

The viral infection of plants may cause various physiological symptoms associated with the reprogramming of plant gene expression. However, the molecular mechanisms and associated genes underlying disease symptom development in plants infected with viruses are largely unknown. In this study, we employed RNA sequencing for in-depth molecular characterization of the transcriptional changes associated with the development of distinct symptoms induced by tomato chlorosis virus (ToCV) and tomato yellow leaf curl virus (TYLCV) in tomato. Comparative analysis of differentially expressed genes revealed that ToCV and TYLCV induced distinct transcriptional changes in tomato and resulted in the identification of important genes responsible for the development of symptoms of ToCV (i.e., chlorosis and anthocyanin accumulation) and TYLCV (i.e., yellowing, stunted growth, and leaf curl). Our comprehensive transcriptome analysis can provide molecular strategies to reduce the severity of disease symptoms as well as new insights for the development of virus-resistant crops.