Allelic variation at the rpv1 locus controls partial resistance to Plum pox virus infection in Arabidopsis thaliana

Sharka is caused by Plum pox virus (PPV) in stone fruit trees. In orchards, the virus is transmitted by aphids and by grafting. In Arabidopsis, PPV is transferred by mechanical inoculation, by biolistics and by agroinoculation with infectious cDNA clones. Partial resistance to PPV has been observed in the Cvi-1 and Col-0 Arabidopsis accessions and is characterized by a tendency to escape systemic infection. Indeed, only one third of the plants are infected following inoculation, in comparison with the susceptible Ler accession. Genetic analysis showed this partial resistance to be monogenic or digenic depending on the allelic configuration and recessive. It is detected when inoculating mechanically but is overcome when using biolistic or agroinoculation. A genome-wide association analysis was performed using multiparental lines and 147 Arabidopsis accessions. It identified a major genomic region, rpv1. Fine mapping led to the positioning of rpv1 to a 200 kb interval on the long arm of chromosome 1. A candidate gene approach identified the chloroplast phosphoglycerate kinase (cPGK2) as a potential gene underlying the resistance. A virus-induced gene silencing strategy was used to knock-down cPGK2 expression, resulting in drastically reduced PPV accumulation. These results indicate that rpv1 resistance to PPV carried by the Cvi-1 and Col-0 accessions is linked to allelic variations at the Arabidopsis cPGK2 locus, leading to incomplete, compatible interaction with the virus.Sharka Containmen

Molecular basis of virus resistance mediated by host factors required for the infectious cycle

National audienceln recent year, one of the most interesting results that has enabled plant virology to make a significant step forward is the identification of components of the translation initiation complex as essential host factors required for RNA virus multiplication. Although translation initiation factors were demonstrated to be highly conserved determinants of plant resistance to viruses, preliminary data indicate that the molecular basis underlying translation initiation factors-mediated resistance are highly variable. ln parallel, several recessive resistance genes against viruses were identified and demonstrated to be distinct from translation initiation factors. These genes are therefore very good candidates for the discovery of new susceptibility factors. ln this context, the MOVle project airns at (i) the characterization of mechanisms underlying molecular specificity of translation initiation factors mediated resistance, (ii) the study of the potential role of translation initiation factors in RNA virus resistance in economically important crops such as grapevine, and (iii) the identification of new host factors required for viral infection The project is likely to provide fundamental insights into the molecular basis of plant-virus interactions and to greatly facilitate the exploitation of host factors required for the viral cycle as targets to improve plant resistance to viruses

Political and industrial relations turbulence, competition and budgeting in the nationalised jute mills of Bangladesh

This paper reports an empirical investigation, based on triangulation methods, of how a set of environmental facts affect budgeting characteristics in the nationalised jute mills of Bangladesh. The key factors were derived from intensive fieldwork. Five external factors (political climate, industrial relations, competition, aid agencies and government regulations) were deemed to affect budget-related factors (such as participation, accountability for budget, budget evaluation, budget analysis, interactions among managers and budget flexibility). Data from 38 state-owned jute mills within the Bangladesh Jute Mills Corporation (BJMC) are used to test the propositions. The analyses of data reveal a significant relationship between environmental factors and budget-related behaviour. Political factors, industrial relations and market competition were major influences on how budgeting systems were perceived. The study shows how political volatility and industrial relations can render the formal systems of budgeting and controls ineffective for internal management despite worthy intentions. On the other hand, when managers believed external competition on their mill to be great, they perceived budgeting more positively

Co-opting ATP-generating glycolytic enzyme PGK1 phosphoglycerate kinase facilitates the assembly of viral replicase complexes

The intricate interactions between viruses and hosts include exploitation of host cells for viral replication by using many cellular resources, metabolites and energy. Tomato bushy stunt virus (TBSV), similar to other (+)RNA viruses, induces major changes in infected cells that lead to the formation of large replication compartments consisting of aggregated peroxisomal and ER membranes. Yet, it is not known how TBSV obtains the energy to fuel these energy-consuming processes. In the current work, the authors discovered that TBSV co-opts the glycolytic ATP-generating Pgk1 phosphoglycerate kinase to facilitate the assembly of new viral replicase complexes. The recruitment of Pgk1 into the viral replication compartment is through direct interaction with the viral replication proteins. Altogether, we provide evidence that the ATP generated locally within the replication compartment by the co-opted Pgk1 is used to fuel the ATP-requirement of the co-opted heat shock protein 70 (Hsp70) chaperone, which is essential for the assembly of new viral replicase complexes and the activation of functional viral RNA-dependent RNA polymerase. The advantage of direct recruitment of Pgk1 into the virus replication compartment could be that the virus replicase assembly does not need to intensively compete with cellular processes for access to ATP. In addition, local production of ATP within the replication compartment could greatly facilitate the efficiency of Hsp70-driven replicase assembly by providing high ATP concentration within the replication compartment