Changes in Turnip Leaf Messenger RNA Populations During Systemic Infection by Severe and Mild Strains of Cauliflower Mosaic Virus

1988 ◽  
Vol 1 (6) ◽  
pp. 243 ◽  
Author(s):  
Rebecca Stratford
Author(s):  
Roberto Alers-Velazquez ◽  
Sushant Khandekar ◽  
Clare Muller ◽  
Jennifer Boldt ◽  
Scott Leisner

AbstractLower temperatures delayed development of systemic symptoms by Cauliflower mosaic virus (CaMV) in two different plant hosts. However, lower temperature exposure increased CaMV nucleic acid levels in leaves of systemically-infected turnips. Furthermore, lower temperature altered the formation of aggregates formed by the CaMV major inclusion body (IB) protein, P6. Finally, lower temperature altered the architecture of the actin cytoskeleton. These data may suggest that lower temperatures alter the actin cytoskeleton, facilitating the formation of larger IBs that hold on to their internal virions more strongly than small ones, impairing virus particle release and causing a delay in systemic infection.


2002 ◽  
Vol 15 (10) ◽  
pp. 1050-1057 ◽  
Author(s):  
Yongzhong Li ◽  
Scott M. Leisner

The Cauliflower mosaic virus (CaMV) gene VI product (P6) is a multifunctional protein essential for viral propagation. It is likely that at least some of these functions require P6 self-association. The work described here was performed to confirm that P6 self-associates and to identify domains involved in this interaction. Yeast two-hybrid analyses indicated that full-length P6 self-associates and that this interaction is specific. Additional analyses indicated that at least four independent domains bind to full-length P6. When a central domain (termed domain D3) was removed, these interactions were abolished. However, this deleted P6 was able to bind to the full-length wild-type protein and to isolated domain D3. Viruses lacking domain D3 were incapable of producing a systemic infection. Isolated domain D3 was capable of binding to at least two of the other domains but was unable to self-associate. This suggests that domain D3 facilitates P6 self-association by binding to the other domains but not itself. The presence of multiple domains involved in P6 self-association may help explain the ability of this protein to form the intracellular inclusions characteristic of caulimoviruses.


2007 ◽  
Vol 20 (6) ◽  
pp. 659-670 ◽  
Author(s):  
Andrew J. Love ◽  
Valérie Laval ◽  
Chiara Geri ◽  
Janet Laird ◽  
A. Deri Tomos ◽  
...  

We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) signaling to infection by Cauliflower mosaic virus (CaMV). Mutants cpr1-1 and cpr5-2, in which SA-dependent defense signaling is activated constitutively, were substantially more resistant than the wild type to systemic infection, implicating SA signaling in defense against CaMV. However, SA-deficient NahG, sid2-2, eds5-1, and pad4-1 did not show enhanced susceptibility. A cpr5 eds5 double mutant also was resistant, suggesting that resistance in cpr5 may function partially independently of SA. Treatment of cpr5 and cpr5 eds5, but not cpr1, with salicyl-hydroxamic acid, an inhibitor of alternative oxidase, partially restored susceptibility to wild-type levels. Mutants etr1-1, etr1-3, and ein2-1, and two mutants with lesions in ET/JA-mediated defense, eds4 and eds8, also showed reduced virus susceptibility, demonstrating that ET-dependent responses also play a role in susceptibility. We used a green fluorescent protein (GFP)-expressing CaMV recombinant to monitor virus movement. In mutants with reduced susceptibility, cpr1-1, cpr5-2, and etr1-1, CaMV-GFP formed local lesions similar to the wild type, but systemic spread was almost completely absent in cpr1 and cpr5 and was substantially reduced in etr1-1. Thus, mutations with enhanced systemic acquired resistance or compromised ET signaling show diminished long-distance virus movement.


2003 ◽  
Vol 16 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Weichang Yu ◽  
Jane Murfett ◽  
James E. Schoelz

The gene VI protein (P6) of Cauliflower mosaic virus (CaMV) functions as a virulence factor in crucifers by eliciting chlorotic symptoms in infected plants. The ability to induce chlorosis has been associated previously with P6 through gene-swapping experiments between strains and through the development of transgenic plants that express P6. The primary role that has been identified for P6 in the CaMV infection cycle is to modify the host translation machinery to facilitate the translation of the polycistronic CaMV 35S RNA. This function for P6 has been designated as the translational transactivator (TAV) function. In the present study, we have characterized an unusual variant of P6, derived from CaMV strain D4, that does not induce chlorosis upon transformation into Arabidopsis thaliana. The level of D4 P6 produced in transgenic Arabidopsis line D4-2 was comparable to the amount found in transgenic plants homozygous for W260 and CM1841 P6, two versions of P6 that induce strong chlorotic symptoms and stunting in Arabidopsis. A complementation assay proved that P6 expressed in the D4-2 line was functional, as it could support the systemic infection of a CM1841 mutant that contained a lethal frame-shift mutation within gene VI. This complementation assay allowed us to separately assess the contribution of CM1841 gene VI to symptom development versus the contribution of other CM1841 genes. Furthermore, a previous study had shown that the TAV activity of D4 P6 was comparable to that of W260 P6. That comparative analysis of TAV function, coupled with the characterization of the D4-2 transgenic line in the present paper, indicates that the TAV function of P6 may play only a minor role in the development of chlorotic symptoms.


1997 ◽  
Vol 10 (6) ◽  
pp. 691-699 ◽  
Author(s):  
Patricio Arce-Johnson ◽  
Ulrich Reimann-Philipp ◽  
Hal S. Padgett ◽  
Rafael Rivera-Bustamante ◽  
Roger N. Beachy

Systemic spread of tobacco mosaic virus (TMV) that lacks a functional movement protein (TMVΔMP) was investigated in grafted tobacco (Nicotiana tabacum) plants. Transgenic plants that express the 30-kDa movement protein (MP) gene (MP) under the control of the rolC (phloem-specific) or pal2 (xylem-specific) promoters were unable to support systemic infection by the mutant virus, while plants that express the MP gene from the cauliflower mosaic virus 35S promoter (35S:MP) led to systemic infection. Doubly grafted plants were constructed in which plants containing the 35S:MP gene were used as root stock and plants carrying various MP constructs constituted the middle scion. The upper scion contained the 35S:MP gene in plants that produce a hypersensitive response when systemically infected by TMV. TMVΔMP moved systemically and produced complete necrosis in the upper scion when expression of MP in the middle scion was under the control of the rolC or 35S promoter, but not when the pal2 promoter was used. When plants expressing a gene encoding a defective MP were used as the middle scion, there was no systemic infection by TMVΔMP, and a delay in systemic infection by wild-type TMV. In grafted plants with middle scions that expressed the TMV 54 kDa gene sequence there was no apparent systemic infection by TMVΔMP in the upper scion. The results obtained indicate that the MP has a role in long distance movement, and support the suggestion that replication is necessary for systemic infection of these grafted plants.


1997 ◽  
Vol 87 (8) ◽  
pp. 792-798 ◽  
Author(s):  
W. Tang ◽  
S. M. Leisner

Arabidopsis thaliana ecotype En-2 was previously shown to be resistant to cauliflower mosaic caulimovirus (CaMV) isolate CM4-184. In this study, En-2 plants were screened with eight other isolates of CaMV to identify viruses capable of overcoming resistance and to determine if the mechanism of resistance was the same for each virus. En-2 resistance to most CaMV isolates was mediated by the same mechanism, i.e., preventing virus long-distance movement. One CaMV isolate, NY8153, was found that produced a severe systemic infection on En-2 plants. In addition, the CM1841 isolate was able to spread systemically through En-2 plants, to a limited extent, without producing visible symptoms. These data indicate that the resistance shown by En-2 plants is not an all-or-none phenomenon. En-2 plants were susceptible to turnip mosaic potyvirus, suggesting that resistance is specific to CaMV.


2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 542-544
Author(s):  
R. Pokorný ◽  
M. Porubová

Under greenhouse conditions 12 maize hybrids derived from crosses of four resistant lines with several lines of different level of susceptibility were evaluated for resistance to Czech isolate of Sugarcane mosaic virus (SCMV). These hybrids were not fully resistant to isolate of SCMV, but the symptoms on their newly growing leaves usually developed 1 to 3 weeks later in comparison with particular susceptible line, the course of infection was significantly slower and rate of infection lower. As for mechanisms of resistance, the presence of SCMV was detected by ELISA in inoculated leaves both of resistant and susceptible lines, but virus was detected 7 days later in resistant line. Systemic infection developed only in susceptible lines. These results indicate restriction of viral long distance movement in the resistant line.


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