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Histone ubiquitylation/deubiquitylation plays a major role in the epigenetic regulation of gene expression. In plants, OTLD1, a member of the ovarian tumor (OTU) deubiquitinase family, deubiquitylates histone 2B and represses the expression of genes involved in growth, cell expansion, and hormone signaling. OTLD1 lacks the intrinsic ability to bind DNA. How OTLD1, as well as most other known plant histone deubiquitinases, recognizes its target genes remains unknown. Here, we show that Arabidopsis transcription factor LSH10, a member of the ALOG protein family, interacts with OTLD1 in living plant cells. Loss-of-function LSH10 mutations relieve the OTLD1-promoted transcriptional repression of the target genes, resulting in their elevated expression, whereas recovery of the LSH10 function results in down-regulated transcription of the same genes. We show that LSH10 associates with the target gene chromatin as well as with DNA sequences in the promoter regions of the target genes. Furthermore, without LSH10, the degree of H2B monoubiquitylation in the target promoter chromatin increases. Hence, our data suggest that OTLD1-LSH10 acts as a co-repressor complex potentially representing a general mechanism for the specific function of plant histone deubiquitinases at their target chromatin. The plant histone deubiquitinase, OTLD1, interacts with the Arabidopsis transcription factor, LSH10, and both transcriptionally regulate a set of common target genes. [ABSTRACT FROM AUTHOR]

Tobacco mosaic virus (TMV) is one of the most economically damaging plant viruses because of its wide host range and transmission mode. TMV manipulates the plant to produce viral proteins, instead of resistant ones. However, microbes with pathogenic defenses have been beneficial against the biotic stress caused by TMV. Through DNA metabarcoding, the microbe communities between parts of the phyllosphere and rhizosphere infected by TMV were compared over a two-week period. Overall, there was a variation of microbial presence and higher species richness in the mock-inoculated than viral inoculated plants. After one week, the mock inoculated plant organs had higher species richness than viral inoculated plant organs due to the presence of viral threat. After two weeks, the viral inoculated soil had the second highest species richness due to the soil being colonized and the presence of defense mechanisms. In addition, there was a wide range of taxa present such as Proteobacteria, Bacteroidetes, Acidobacteria, and Cyanobacteria. [ABSTRACT FROM AUTHOR]

Cell-to-cell movement is an important step for initiation and spreading of virus infection in plants. This process occurs through the intercellular connections, termed plasmodesmata (PD), and is usually mediated by one or more virus-encoded movement proteins (MP) which interact with multiple cellular factors, among them protein kinases that usually have negative effects on MP function and virus movement. In this study, we report physical and functional interaction between MP of Tobacco mosaic virus (TMV), the paradigm of PD-moving proteins, and a receptor-like kinase BAM1 from Arabidopsis and its homolog from Nicotiana benthamiana. The interacting proteins accumulated in the PD regions, colocalizing with a PD marker. Reversed genetics experiments, using BAM1 gain-of-function and loss-of-function plants, indicated that BAM1 is required for efficient spread and accumulation the virus during initial stages of infection of both plant species by TMV. Furthermore, BAM1 was also required for the efficient cell-to-cell movement of TMV MP, suggesting that BAM1 interacts with TMV MP to support early movement of the virus. Interestingly, this role of BAM1 in viral movement did not require its protein kinase activity. Thus, we propose that association of BAM1 with TMV MP at PD facilitates the MP transport through PD, which, in turn, enhances the spread of the viral infection. Tran and Citovsky show that receptor-like kinase BAM1 is required for efficient spread and the accumulation of the virus during initial stages of infection of Arabidopsis and Nicotiana by Tobacco mosaic virus (TMV). This study provides insights into the TMV's transmission mechanism in plants. [ABSTRACT FROM AUTHOR]

In 2017, we collected tomato leaf tissues showing symptoms such as yellowing, mosaic, and stunting from six different regions in Bao Loc city of Vietnam. As judged from the NGS data, all tomato samples used in this study were also co-infected with tomato mosaic virus, tomato yellow leaf curl Kanchanaburi virus, and capsicum chlorosis virus. [Extracted from the article]