Viruses are one of infectious pathogens. Like other plants, plumerias can be infested with viruses. The particular types of viruses such as Frangipani Mosaic virus (FrMV) found in infested plumeria may cause discolorations and/or distortions in leaves and flowers and stunt the plant growth. The symptoms are highly variable, depending on the variety and the environment. Knowing the nature of FrMV (especially viral transmission) as well as using precaution when handling the plants are the key steps in preventing it from spreading. FrMV and its symptoms found in plumeria in Thailand are emphasized on this page. Coloration markings caused by FrMV and by other means are also mentioned here.
Virus causing Color Break in Plumeria
Figure 1. Vishanu Gold plumeria: normal coloration (left), viral symptom on flower (middle), and viral symptom on leaves (right)
Figure 2. Phoung Yok plumeria: normal coloration (left), viral symptom on flower (middle), and viral symptom on leaves (right)
Figure 3. Dwarf Singapore Pink plumeria: normal coloration (left), viral symptom on flower (middle), and viral symptom on leaves (right)
Figure 4. Confetti plumeria: normal coloration (left), viral symptom on flower (middle), and viral symptom on leaves (right)
Figure 5. Viral symptom on flowers - (from left to right) J105, My Valentine, Bali Whirl, Rim Fire, Mary Helen Eggenberger and Vera Cruz Rose plumeria
Figure 6. Viral symptom in purple plumerias - Muang Maong Rat (left), Muang Phoung Roi (middle), and P-26 (right)
Figure 7. A typical bleed-like symptom caused by a FrMV in light yellow colored plumerias (low in anthocyanin) - Celedine (left), Bali Whirl (middle), and Traditional White (right)
Figure 8. Viral symptoms with various patterns, sizes and shapes randomly located on petal tissues. Symptoms of the disease vary among plumeria species and cultivars.
Figure 9. Viral Symptom on petioles - Coral Cream (left), Phoung Yok (middle), and Unknown plumeria (right)
Figure 10. Viral symptom on leaves - (from left to right) Kled Tabtim, Buddha Raksa, unknown, Moung Phoung Roi, and two Unknown plumerias
Figure 11. Viral symptoms developed on leaves of virused plumerias after bud-grafting - Jamaica Fire (left) and two unknown plumerias (middle and right)
Figure 12. The progression of viral symptom in plumeria leaves from an early stage of leaf enlargement and maturation (stage #1) to fully stage (stage #5). The images of viral symptom at various stages of leaf enlargement and maturation were taken at 2-3 days apart showing the continuously changing viral mosaic patterns due to viral activity in progress. Notice the symptom only starts to appear in the emerging leaf (not in other later stages) and its pattern evolves further when the leaf gets larger in size until it reaches maturation stage.
Dey, K.K. 2019. First Report of Frangipani mosaic virus Infecting Frangipani 2 ( Plumeria spp) in the USA. Plant Disease.
https://www.researchgate.net/publication/338078964_First_Report_of_Frangipani_mosaic_virus_Infecting_Frangipani_2_Plumeria_spp_in_the_USA
Virus causing Color Break in Plumeria
Based upon field/laboratory tests and observation of infected plumeria plants from various places for a number of years, it comes into a conclusion that Frangipani Mosaic Virus has a minimal effect on the growth and the health of most plumerias with the exception of severe cases in a few cultivars. Its symptoms may include, e.g., leaf malformation, mottled leaf, and/or non-uniform splash or color break (CB), especially on the petals. Some plumeria trees appear normal with only an occasional CB on the petals, which is attractive to some people. From my point of view, however, the color break is unacceptable since it distorts the original colors of flowers. In addition, unlike other diseases, it is incurable, and the virus that resides in the infected plant may accidently spread to other plumeria trees somehow, and finally, the whole collection may all be infected.
According to DPV web, the FrMV transmitted by mechanical inoculation not involving a vector. FrMV hardly spreads in plumerias especially in the wild probably due to the lack of natural carrier for this particular virus. Gaining popularity in the past two decades, plumeria has been vegetatively propagated in mass for sale. Many growers did not take any precautions when taking cuttings or making grafts. Viral-contaminated cutting tools used in grafting and pruning become the most common means of FrMV transmission. Unfortunately, it is how this particular virus spreads rapidly and covertly in plumerias, especially in Thailand and recently in the plumerias exported to the US and the rest of the world. Nowadays, its symptoms are commonly seen in plumerias which are sold in the markets in a number of countries. Some virused plumerias may look normal, but the symptoms generally appear in a later stage. Thus it is important to address this issue to increase growers' awareness, to keep the virus under control, and to save all great plumeria cultivars from being infected.
In an attempt to keep the whole plumeria collection virus-free, newly acquired plumerias first should be isolated over a period of time to observe or check (test) for the presence of virus. All FrMV-infected plants should be separated from the rest of collection and/or destroyed. Using a sterilized cutting tool is also the key to preventing the spread of the FrMV, which may be present in the plumeria trees growing in the garden, to the rest of the collection. My routine practice of pruning plumerias in the garden is to carry as many sterilized knives as possible with me and use only one knife per plumeria plant. They are then sterilized in boiling water for at least 10 min. for further use.
Plumerias with the virus should not be allowed to be registered as a new cultivar based upon its appearance of the flowers with the color break. It is just a diseased plant, not an innovative one.
FrMV and Symptoms in Plumeria
Transmission:
*FrMV is transmitted primarily through cutting or trimming the plants. Contact of the infected plant's sap with sap of a healthy plant will infect the new plant. This can happen whenever cuts are made and the cutting/grafting tools, hands or workbenches are not disinfected afterwards. After infection with a virus, it enters a plant cell (in the form of virion) via wounds and performs a process of cell-to-cell movement by being transported through plasmodesmata (microscopic channels bettween cells). In the process, it slowly spreads at the rate of one hour to a few hours from an infected cell to the neighbouring cell(s) where more virions are replicated. Once the virions reach the plant vascular system, they are effectively transported in all directions at the rate of centimeters per hour in phloem to all plant parts before moving into surrounding cells where they reproduce and spread by cell-to-cell movement, and eventually colonize the entire plant. The first sign of symptom in plant may take months or years to appear (depending upon plumeria cultivar, and plant and environmental conditions).
*FrMV resides in infected plant throughout the plant's life. The disease is incurable. Cuttings taken from an infected plant are infected even if no symptoms are immediately exhibited by the cuttings. The only area in the infected plant that virus can not enter is meristem. Meristem-tip culture may be applied to get a new plant with free of virus.
*FrMV does not transmit through seed, resulting in absence of virus in seedling. Like all plumerias, the seedling can be infected with FrMV at any age with poor cultural and sanitation practices.
Favorable conditions:
FrMV may lie dormant within a cell, and the period of the latency in some plumeria cultivars can span for a long time without any symptoms on their flowers and leaves. The mechanism to reverse the latent state is quite complex involving the interaction between the virus and its plant host. The virus is also able to occasionally reactivate via external activators (i.e. stress or the change in environmental conditions or any other unknown factors) to cause the symptoms to reappear.
*Heat is one of the many factors that can put a lot of stress on a plant, and provides favorable condition for FrMV residing in the plant to grow. FrMV is more active and replicates quickly at a relatively high temperature (best at 30-35C or 86-95F) but at a slower rate when temperature is outside (lower or higher) of its optimal growth range. Although the extreme and prolonged heat (e.g. 100+F) is not the most ideal condition for FrMV to grow, it can put a lot of stress on the plant host, and the virus can be reactivated from a latent stage to a lytic stage.
It is important to note that it is the VIRUS (not HEAT or other external activators) that is responsible for these unique "viral symptoms" in the virused plumeria plant. The other words, only the plumeria plant infested with the FrMV can exhibit the "viral symptoms" when the condition(s) is right, but the non-virused plant never ever does.
*Grafting (especially bud grafting) is another factor that causes a lot of stress on a plant. If either rootststock or scion used in grafting is from virused plant(s), the entire graft is infected. The viral symptom likely appears on emerging leaves of the newly grafted plant. Again, it is the VIRUS (not GRAFTING) that is responsible for the viral symptom on the leaves.
Symptoms:
The symptoms of viral disease result from the immune response to the virus, which attempts to control and eliminate the virus from the plant and from cell damage caused by the virus.
*FrMV replication causes a change in color pattern of pigmented flower/leaf by intensification and overaccumulation of epidermal anthocyanin pigments in the petals/leaves (anthocyanescene). Note: Anthocyanescence is the development of reddish/purplish hues within the context of normal coloration by the accumulation of anthocyanin.)
*Looks for the virus lesions on a newly emerging leaf and flower. These are where the symptoms first reveal themselves (before evolving further with leaf or flower age) and are a strong indication of FrMV evidence.
*FrMV affects different plumeria cultivars/species in different ways (dependent on genetic background of the host plants), so it is impossible to give a definitive description of symptoms. Besides plumeria cultivars, the symptoms may vary with plant's parts (e.g. flower, leaf, petiole and etc.), viral strains and environmental conditions. Yet there are some common characteristics among infected plants; including irregular mottled/splotchy markings or dark striations of various sizes and shapes on the leaves, and non-uniform dark red/moroon splashes (color breaks) of various forms and size unevenly/unpredictably distributed on the flower petals and non-consistent patterns from flower to flower (Fig. 1 to 9).
Depending on how people view it, the color breaks on flower petals may look like a "dark red/maroon paint splatter" in painted pictures or "blood splatter" at a crime scene in J105 plumeria cultivar, or "blood or red paint bleeds" in watercolor in Bali Whirl cultivar (Fig. 5). Unlike flowers, leaves can stay on the tree for a longer time; therefore, the viral mottled markings or the dark striations may change in size, color and shape as the leaves expand and the symptom progresses into surrounding tissue of the leaves. The color of mottled makings generally fades when the leaves mature and age.
*Infection does not always result in visible symptoms at all time. In case of having visible symptoms, they may exhibit only on either flowers or leaves or display on both flowers and leaves at the same time. In case of Plumerias (e.g. Plumeria alba) with pure white flowers (no anthocyanin pigment), the symptom only appears on leaves.
*FrMV does not kill plumeria plant. Most virused plumerias are apparently normal with symptoms which occasionally appear on a few flowers and/or a few leaves. Some cultivars may frequently (or hardly) exhibit symptoms especially the color breaks on flower petals. However, the growth of a few cultivars may be severely impaired by FrMV infection.
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| Symptom caused by a virus in Vishanu Gold |
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| The Original color of virus-free Vishanu Gold |
According to DPV web, the FrMV transmitted by mechanical inoculation not involving a vector. FrMV hardly spreads in plumerias especially in the wild probably due to the lack of natural carrier for this particular virus. Gaining popularity in the past two decades, plumeria has been vegetatively propagated in mass for sale. Many growers did not take any precautions when taking cuttings or making grafts. Viral-contaminated cutting tools used in grafting and pruning become the most common means of FrMV transmission. Unfortunately, it is how this particular virus spreads rapidly and covertly in plumerias, especially in Thailand and recently in the plumerias exported to the US and the rest of the world. Nowadays, its symptoms are commonly seen in plumerias which are sold in the markets in a number of countries. Some virused plumerias may look normal, but the symptoms generally appear in a later stage. Thus it is important to address this issue to increase growers' awareness, to keep the virus under control, and to save all great plumeria cultivars from being infected.
In an attempt to keep the whole plumeria collection virus-free, newly acquired plumerias first should be isolated over a period of time to observe or check (test) for the presence of virus. All FrMV-infected plants should be separated from the rest of collection and/or destroyed. Using a sterilized cutting tool is also the key to preventing the spread of the FrMV, which may be present in the plumeria trees growing in the garden, to the rest of the collection. My routine practice of pruning plumerias in the garden is to carry as many sterilized knives as possible with me and use only one knife per plumeria plant. They are then sterilized in boiling water for at least 10 min. for further use.
Plumerias with the virus should not be allowed to be registered as a new cultivar based upon its appearance of the flowers with the color break. It is just a diseased plant, not an innovative one.
FrMV and Symptoms in Plumeria
Transmission:
*FrMV is transmitted primarily through cutting or trimming the plants. Contact of the infected plant's sap with sap of a healthy plant will infect the new plant. This can happen whenever cuts are made and the cutting/grafting tools, hands or workbenches are not disinfected afterwards. After infection with a virus, it enters a plant cell (in the form of virion) via wounds and performs a process of cell-to-cell movement by being transported through plasmodesmata (microscopic channels bettween cells). In the process, it slowly spreads at the rate of one hour to a few hours from an infected cell to the neighbouring cell(s) where more virions are replicated. Once the virions reach the plant vascular system, they are effectively transported in all directions at the rate of centimeters per hour in phloem to all plant parts before moving into surrounding cells where they reproduce and spread by cell-to-cell movement, and eventually colonize the entire plant. The first sign of symptom in plant may take months or years to appear (depending upon plumeria cultivar, and plant and environmental conditions).
*FrMV resides in infected plant throughout the plant's life. The disease is incurable. Cuttings taken from an infected plant are infected even if no symptoms are immediately exhibited by the cuttings. The only area in the infected plant that virus can not enter is meristem. Meristem-tip culture may be applied to get a new plant with free of virus.
*FrMV does not transmit through seed, resulting in absence of virus in seedling. Like all plumerias, the seedling can be infected with FrMV at any age with poor cultural and sanitation practices.
Favorable conditions:
FrMV may lie dormant within a cell, and the period of the latency in some plumeria cultivars can span for a long time without any symptoms on their flowers and leaves. The mechanism to reverse the latent state is quite complex involving the interaction between the virus and its plant host. The virus is also able to occasionally reactivate via external activators (i.e. stress or the change in environmental conditions or any other unknown factors) to cause the symptoms to reappear.
*Heat is one of the many factors that can put a lot of stress on a plant, and provides favorable condition for FrMV residing in the plant to grow. FrMV is more active and replicates quickly at a relatively high temperature (best at 30-35C or 86-95F) but at a slower rate when temperature is outside (lower or higher) of its optimal growth range. Although the extreme and prolonged heat (e.g. 100+F) is not the most ideal condition for FrMV to grow, it can put a lot of stress on the plant host, and the virus can be reactivated from a latent stage to a lytic stage.
It is important to note that it is the VIRUS (not HEAT or other external activators) that is responsible for these unique "viral symptoms" in the virused plumeria plant. The other words, only the plumeria plant infested with the FrMV can exhibit the "viral symptoms" when the condition(s) is right, but the non-virused plant never ever does.
*Grafting (especially bud grafting) is another factor that causes a lot of stress on a plant. If either rootststock or scion used in grafting is from virused plant(s), the entire graft is infected. The viral symptom likely appears on emerging leaves of the newly grafted plant. Again, it is the VIRUS (not GRAFTING) that is responsible for the viral symptom on the leaves.
Symptoms:
The symptoms of viral disease result from the immune response to the virus, which attempts to control and eliminate the virus from the plant and from cell damage caused by the virus.
*FrMV replication causes a change in color pattern of pigmented flower/leaf by intensification and overaccumulation of epidermal anthocyanin pigments in the petals/leaves (anthocyanescene). Note: Anthocyanescence is the development of reddish/purplish hues within the context of normal coloration by the accumulation of anthocyanin.)
*Looks for the virus lesions on a newly emerging leaf and flower. These are where the symptoms first reveal themselves (before evolving further with leaf or flower age) and are a strong indication of FrMV evidence.
*FrMV affects different plumeria cultivars/species in different ways (dependent on genetic background of the host plants), so it is impossible to give a definitive description of symptoms. Besides plumeria cultivars, the symptoms may vary with plant's parts (e.g. flower, leaf, petiole and etc.), viral strains and environmental conditions. Yet there are some common characteristics among infected plants; including irregular mottled/splotchy markings or dark striations of various sizes and shapes on the leaves, and non-uniform dark red/moroon splashes (color breaks) of various forms and size unevenly/unpredictably distributed on the flower petals and non-consistent patterns from flower to flower (Fig. 1 to 9).
Depending on how people view it, the color breaks on flower petals may look like a "dark red/maroon paint splatter" in painted pictures or "blood splatter" at a crime scene in J105 plumeria cultivar, or "blood or red paint bleeds" in watercolor in Bali Whirl cultivar (Fig. 5). Unlike flowers, leaves can stay on the tree for a longer time; therefore, the viral mottled markings or the dark striations may change in size, color and shape as the leaves expand and the symptom progresses into surrounding tissue of the leaves. The color of mottled makings generally fades when the leaves mature and age.
*Infection does not always result in visible symptoms at all time. In case of having visible symptoms, they may exhibit only on either flowers or leaves or display on both flowers and leaves at the same time. In case of Plumerias (e.g. Plumeria alba) with pure white flowers (no anthocyanin pigment), the symptom only appears on leaves.
*FrMV does not kill plumeria plant. Most virused plumerias are apparently normal with symptoms which occasionally appear on a few flowers and/or a few leaves. Some cultivars may frequently (or hardly) exhibit symptoms especially the color breaks on flower petals. However, the growth of a few cultivars may be severely impaired by FrMV infection.
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Articles on Viruses infecting Plumeria:
Frangipani Mosaic Virus (FrMV) - Tobamovirus
Plumeria Mosaic Virus (PluMV) - Tobamovirus
Groundnut Ringspot Virus (GRSV) - Orthotospovirus
Virus Taxonomy: 2021 Release
Genus: Tobamovirus
Species: Frangipani mosaic virus (FrMV) and Plumeria mosaic virus (PluMV)
Francki, R. I. B., et al. 1971. An Unusual Strain of Tobacco Mosaic Virus From Plumeria acutifolia. J. Biol. Sci. 24:811.
Gibbs. A.J. 1977. Tobamovirus group. In Description of Plant Viruses. DPV no. 184.
Verma, A. and Gibbs, A.J. 1978. Frangipani Mosaic Virus. In Description of Plant Viruses. DPV no. 196.
Xiaodong, D., et. al. 2000. Cloning and Sequencing of the 3'-end of Frangipani Mosaic Virus (FrMV). J. Trop. and Subtrop. Bot. 8(3):185-192.
Lim, M.A., et. al. 2010. The complete genome sequence and genome structure of frangipani mosaic virus. Archives of Virology. 155:1543–1546.Kumar A., et al. 2013. Frangipani mosaic virus and Plumeria mosaic virus: Identification and Comparison of two tobamovirus infecting Frangipani in India. Proceedings of the Asia-Pacific Congress of Virology, 2013, at Amity University Noida.
Kumar, A., et al. 2015. Characterisation and diagnosis of frangipani mosaic virus from India. Virus Genes. 51:310.
https://doi.org/10.1007/s11262-015-1228-3
https://doi.org/10.1007/s11262-015-1228-3
Kumar, A. and Mandal, B. 2015. Plumeria mosaic virus isolate Plu-Ind-1, complete genome. In Molecular characterization of a new tobamovirus, Plumeria mosaic virus. unpublished
https://www.ncbi.nlm.nih.gov/nuccore/KJ395757Choliq, F.A., et.al., 2017. Molecular Characterization of a Rigid Rod-Shaped Virus Isolated from Frangipani (Plumeria sp.) Showing Mosaic Symptom in Taiwan. J. Exp. Life Sci. 7:1.
Dey, K.K., et. al., 2017. First Report of Frangipani Mosaic Virus Infecting Frangipani (Plumeria spp.) in the U.S.A. The American Phytopathological Society (APS).
https://doi.org/10.1094/PDIS-09-19-2003-https://www.researchgate.net/publication/338078964_First_Report_of_Frangipani_mosaic_virus_Infecting_Frangipani_2_Plumeria_spp_in_the_USA
Lotgen, H., et al. 2022. First report of Plumeria mosaic virus infecting Plumeria spp. in the United States. Plant Disease.
2022 Nov 6. doi: 10.1094/PDIS-09-22-2019-PDN. Online ahead of print.
PMID: 36336670
G.M. Favara., et al. 2023. Infection of groundnut ringspot virus in plumeria pudica characterized by irregular virus distribution and intermittent expression of symptoms. Front. Plant Sci. Sec. Plant Pathogen Interactions. vol. 14.