Anderson G.,University of Kentucky |
Wang R.,University of Kentucky |
Bandyopadhyay A.,Mahyco Life Science Research Center |
Goodin M.,University of Kentucky
Frontiers in Plant Science | Year: 2012
Potato yellow dwarf virus (PYDV is the type species of the genus Nucleorhabdovirus and, like all members of this genus, replication and morphogenesis occurs inside the nuclei of infected cells. Protein localization prediction algorithms failed to identify a nuclear localization signal (NLS in PYDV nucleocapsid (N protein, although PYDV-N has been shown to localize exclusively to the nucleus when expressed as a green fluorescent protein (GFP:N fusion in plant cells. Deletion analysis using fragments of PYDV-N identified a karyophilic region in the carboxy-terminal 122 amino acids. Alanine-scanning mutagenesis was performed across this region in the context of the full-length N protein. Mutants were assayed for their ability to nuclear localize using live-cell imaging and a yeast-based assay. Two amino acid motifs, 419QKR421 and 432KR433 were shown to be essential for nuclear import and interaction with importin-α. Additional bimolecular fluorescence complementation showed that the PYDV-N-NLS mutants cannot be ferried into the nucleus via interaction with PYDV-P or -M. In contrast, interaction with N-NLS mutants appeared to retard the nuclear import of PYDV-P. GFP fused to aa 419-434 established that the PYDV-N-NLS can function outside the context of this protein. Taken together, it was determined that PYDV-N contains the bipartite NLS 419QKRANEEAPPAAQKR433. © 2012 Anderson, Wang, Bandyopadhyay and Goodin.
Sharma M.,Mahyco Life Science Research Center |
Bhatt D.,Mahyco Life Science Research Center
Molecular Plant Pathology | Year: 2015
The circadian clock is the internal time-keeping machinery in higher organisms. Cross-talk between the circadian clock and a diverse range of physiological processes in plants, including stress acclimatization, hormone signalling, photomorphogenesis and defence signalling, is currently being explored. Recent studies on circadian clock genes and genes involved in defence signalling have indicated a possible reciprocal interaction between the two. It has been proposed that the circadian clock shapes the outcome of plant-pathogen interactions. In this review, we highlight the studies carried out so far on two model plant pathogens, namely Pseudomonas syringae and Hyaloperonospora arabidopsidis, and the involvement of the circadian clock in gating effector-triggered immunity and pathogen-associated molecular pattern-triggered immunity. We focus on how the circadian clock gates the expression of various stress-related transcripts in a prolific manner to enhance plant fitness. An understanding of this dynamic relationship between clock and stress will open up new avenues in the understanding of endogenous mechanisms of defence signalling in plants. © 2014 BSPP AND JOHN WILEY & SONS LTD.