RMV report at the National meeting

A paper was presented Friday at the St Paul, ARS Spring Convention (Program: Consulting Rosarian Seminar * Rose Virus

Ben did a great job. He highlighted the six new rose viruses that he has identified in the past three years. He talked about the four rose viruses just a little bit that lead to rose mosaic symptoms identified between 1930 and 2005. Why did he identify 6 viruses between 2005 and now while only those relatively few were identified in 75 years??? It is because he actually looks for virus with electron microscopy. Others typically just use antibodies to detect the presence or absence of previously characterized viruses that have antibodies developed.

Ben’s work began with Jodi Fetzer sending him samples from the Brooklyn Botanical Garden of suspicious rose leaves. Jodi was the Integrated Pest Management person there and knew Ben from the U of MN when she worked here. ‘Ballerina’ would leaf out and have severe leaflet yellowing and fall early in the season and then necrotic rings on the stems. Many other roses had variable yellowing and viral symptoms.

Ben identified a filamentous virus (long and skinny) in ‘Ballerina’ and others. He subsequently found it in exhibition hybrid teas at the MN Landscape arb and other places as well. I helped him propagate ‘Ballerina’ from the MN landscape arb and graft onto it a hybrid tea that only had the filamentous virus. THe symtoms began to appear in only 2 weeks!!! ‘Ballerina’ is very susceptible and the symptoms match very well with what has been characterized as Rose Streak Disease.

In addition, there is a spherical virus in ‘Ballerina’ that appears to fit a group of virus called cryptic viruses from sequence data and also coat protein and appearance. These viruses are primarily seed transmitted and in general do not supposed to have much of an effect on plant growth, but it has shown visible symptoms. It has been found in ‘First Light’, a ‘Ballerina’ seedling. I will try to get Ben other ‘Ballerina’ descendants. I’m rooting cuttings of ‘Marjorie Fair’ for him know and will try to get other cultivars with ‘Ballerina’ as a female parent. Vance Whitaker has crosses of ‘Ballerina’ x polyanthas he will share with Ben too. Ben characterized a large number of advanced selections from a nursery with an active rose breeding program and found a third of the roses have it.

There are two other viruses that are very large in size and spherical that he has found in ‘Softee’ and ‘Fiesta’ and then also in rugosa cultivars.

He does this work on the side and does not have funding to support it. Funding sources to help promote this work would be very helpful in further characterization of the symptoms each causes, its sequence data, its mode of transmission…

Ben welcomed leaf samples to be sent to him. Someone asked if the slides and pictures he shared would be available from him and also in a future edition of the compendium of rose diseases. He said he could arrange the powerpoint to get to those who wanted it and that he would love for this information to be included in a new edition of the compendium someday.

Perhaps a contribution we can all give would be ideas of ways to fund this work. Ben has generated antibodies to the filamentous virus so it can be indexed now.

We are having a great convention and in a couple hours we will have the rose hybridizers meeting.

Sincerely,

David

Cliff has a lot of Lens hybrids, David. His are from Europe though, so I dunno if that is helpful. At any rate, Lens used Ballerina in a lot of his work.

David, thanks for the update! I am sorry that I missed your talk on Thursday and won’t make it to the RHA meeting. I paid a big price for being two minutes late to the airline ticket counter… I hope to never do that again! Will you be able to summarize your talk either here or in the next RHA Newsletter?

Did Ben make any comments about whether or not striping in modern roses is virus related? I suspect that it is. The “hand-painted” series of roses also have a tendancy for foliage distortion during the heat of summer. I wonder if they might also owe their appearance to a virus effect??

Jim Sproul

Thanks Dave for the report.

The ARS has a separate fund for supporting rose research. The last audit that is on their web page ( http://www.ars.org/pdf/2004Audit.pdf ) indicates that the account has $194,025.00 in it.

Link: www.ars.org/pdf/2004Audit.pdf

The following is a Ph. D. Thesis abstract. I have placed stars around the part that refers to transmission through pollen and ovules.:

UMI # AAI8614034.

AUTHR/ADVSR HANDLEY, MARY KATHRYN.

TITLE IDENTIFICATION AND PARTIAL CHARACTERIZATION OF TWO CRYPTIC VIRUSES IN ROSE BY ANALYSIS OF DOUBLE-STRANDED RNA CONTENT (LEAF CURL, SHOOT-TIP CULTURE, VIRAZOLE)

YEAR 1986.

DESCRIPT 98 p. DEGREE NOTE Thesis (PH.D.)–UNIVERSITY OF CALIFORNIA, DAVIS, 1986. SCHOOL CODE School code: 0029.

SUBJECT Agriculture, Plant Pathology. SUBJ CODE 0480. DEGREE NAME PH.D.

ABSTRACT Two novel patterns of double-stranded RNA (dsRNA) species, termed pattern A and pattern B, were isolated from apparently healthy roses. Pattern A had 3 dsRNAs, with molecular weights of 1.2, 1.1, and 1.05 megadaltons. This pattern was present in 17% of the 160 rose cultivars tested. Pattern B had 2 dsRNAs, with molecular weights of 1.35 and 1.3 megadaltons, and was present in 2 of the 160 rose cultivars tested. These dsRNAs were not transmitted by graft or mechanical inoculations.

*********** Pattern A was transmitted very efficiently through ovules (100%) and pollen (76%).************ The properties of these dsRNAs resemble those of the plant cryptic viruses, which have dsRNA genomes contained in 30 nm icosahedral virus flower petals were used as starting material for virus particle purification, pattern A

dsRNAs were found in higher concentration in high speed pellet (HSP) fractions than in high speed supernatant fractions. During the summer, no dsRNAs could be found in high speed pellets. Particles approximately 30 nm in diameter were found in HSP from pattern A carriers and healthy plants. This evidence indicated that pattern A dsRNAs may be the genomic RNAs of a cryptic virus; however,

much of the dsRNA was not encapsidated, particularly in summer. Rose spring dwarf (RSD) and rose leaf curl (RLC), two virus-like diseases of rose which have unknown causal agents, were not associated with any unique dsRNAs. Pattern A dsRNAs and RSD persisted through thermotherapy. One Rosa multiflora cv. Burr plant which was free of pattern A dsRNAs was produced by shoot-tip culturing. This may be a useful way to generate healthy plant material to investigate the effects of cryptic viruses on their hosts.

NOTE Source: Dissertation Abstracts

International, Volume: 47-04, Section: B, page: 1359.

ALT AUTH

UNIVERSITY OF CALIFORNIA, DAVIS.

The following is a Ph. D. Thesis abstract. I have placed stars around the part that refers to transmission through pollen and ovules.:

UMI # AAI8614034.

AUTHR/ADVSR HANDLEY, MARY KATHRYN.

TITLE IDENTIFICATION AND PARTIAL CHARACTERIZATION OF TWO CRYPTIC VIRUSES IN ROSE BY ANALYSIS OF DOUBLE-STRANDED RNA CONTENT (LEAF CURL, SHOOT-TIP CULTURE, VIRAZOLE)

YEAR 1986.

DESCRIPT 98 p. DEGREE NOTE Thesis (PH.D.)–UNIVERSITY OF CALIFORNIA, DAVIS, 1986. SCHOOL CODE School code: 0029.

SUBJECT Agriculture, Plant Pathology. SUBJ CODE 0480. DEGREE NAME PH.D.

ABSTRACT Two novel patterns of double-stranded RNA (dsRNA) species, termed pattern A and pattern B, were isolated from apparently healthy roses. Pattern A had 3 dsRNAs, with molecular weights of 1.2, 1.1, and 1.05 megadaltons. This pattern was present in 17% of the 160 rose cultivars tested. Pattern B had 2 dsRNAs, with molecular weights of 1.35 and 1.3 megadaltons, and was present in 2 of the 160 rose cultivars tested. These dsRNAs were not transmitted by graft or mechanical inoculations. *********** Pattern A was transmitted very efficiently through ovules (100%) and pollen (76%).************ The properties of these dsRNAs resemble those of the plant cryptic viruses, which have dsRNA genomes contained in 30 nm icosahedral virus flower petals were used as starting material for virus particle purification, pattern A dsRNAs were found in higher concentration in high speed pellet (HSP) fractions than in high speed supernatant fractions. During the summer, no dsRNAs could be found in high speed pellets. Particles approximately 30 nm in diameter were found in HSP from pattern A carriers and healthy plants. This evidence indicated that pattern A dsRNAs may be the genomic RNAs of a cryptic virus; however, much of the dsRNA was not encapsidated, particularly in summer. Rose spring dwarf (RSD) and rose leaf curl (RLC), two virus-like diseases of rose which have unknown causal agents, were not associated with any unique dsRNAs. Pattern A dsRNAs and RSD persisted through thermotherapy. One Rosa multiflora cv. Burr plant which was free of pattern A dsRNAs was produced by shoot-tip culturing. This may be a useful way to generate healthy plant material to investigate the effects of cryptic viruses on their hosts.

NOTE Source: Dissertation Abstracts

International, Volume: 47-04, Section: B, page: 1359.

ALT AUTH

UNIVERSITY OF CALIFORNIA, DAVIS.