VIRUSES & VIRAL PLANTS Pt. 3

As we’ve made our way through the past few blogs, we’ve examined the complex nature that viruses have. We’ve gone in-depth into the realm of viruses and examined two of the most unique virus families in biology. Now, we’ll examine the third and final family of viruses that have the capacity to infect the Animalia and Plantae Kingdoms.

The first of these viruses was the Bunyaviridae and the second was the Rhabdoviridae. The third of these rare viruses that we will be discussing is the Reoviridae family.

As we come to a close on our examinations of rare plant viruses that can infect humans we take one more close look at the dangers these species present.

Reoviridae

The Basics

Reoviridae has 2 subfamilies that have 15 genera that divide out into a total of 75 different virus species that infect a variety of hosts, including plants and animals. This virus family is the largest family of double-stranded RNA viruses, and perhaps the most understood of their kind. They have been identified in a wide variety of organisms, found in everything from an arachnid, a plant, fungi, reptiles, mammals, and more.

In humans, this viral family is responsible for the commonly known Rotavirus. The Rotavirus is passed from fecal matter being transmitted orally through contaminated objects and surfaces. This transmission encourages easier spread amongst children and infants.

But the Reoviridae viruses aren’t exclusive to humans. As mentioned above, the variety of hosts for these viruses almost seems unlimited, even infecting fish! But our major concern is the relationship these viruses have with plants and how we can prevent their spread.

Affect on Plants

Out of the abundance of Reoviridae viruses that exist, there are 3 genera that have approximately 14 different species that infect plants. These three genera are Phytoreovirus, Oryzavirus, and Fijivirus.

These viruses are believed to originate in ancient invertebrates and are developmentally reliant on the vectors of leafhoppers. Without the hoppers the virus could not reproduce in most cases and would die off completely. But, with the hoppers as the host, they are able to spread their diseases to different plant vectors. Due to the lack of spread through seed, many of these viruses reproduce through larvae of the hoppers and not just in the host themselves.

These viruses are mainly a threat to what are known as cereal crops and include rice, maize, sorghum, and barley. Each variation of these viruses affect each crop a little differently, but overall causes severe damage. As we examine these three different viral genera we should keep in mind how each of them could impact our environment if not properly managed.

Phytoreovirus

This virus produces the commonly known diseases of Rice Dwarf Virus and Rice Gall Dwarf Virus. Plants that are infected with these viruses exhibit defined stunting, more tillering, and leaves that are short and dark with chlorotic specks. The plants most often survive until harvest, but at that time it is often discovered that the flower containing the grain is empty.

The damage from these viruses are mostly experienced in Southeastern Asia, but that doesn’t mean it can’t affect other areas of the world. Diseases can often go unnoticed with little symptoms to the plant until harvest time.

This furtiveness can make the management of these pests and diseases almost impossible if not properly maintained. Cleanliness is of the utmost importance when managing stock plants. As part of Plant Sentry’s mission, we maintain constant vigilance on diseases like these to keep our growers informed and their plants healthy.

Orzyavirus

The second genera of the Reoviridae virus family to infect plants is the Orzyavirus. One of its species is the Rice Ragged Stunt Virus. This disease is transmitted by the Brown Planthopper and reduces the amount of plant density and grain production. This virus is most commonly found in tropical Asian climates where the conditions are optimal for continuous habitation of the Brown Planthopper and rice to be grown all year long.

Much like the Phytovirus the threat that this disease poses to crop quality and density is significant. While it primarily occurs in other parts of the world outside the United States, it still has the potential to impact our food supply and the plants that we grow. It is oftentimes that once a species makes its way to our country that a virus or disease mutates and infects its new surroundings differently than it had in its original habitat.

Fijivirus

The last genera of this viral family is the Fijivirus. In recent years these viruses have primarily been found targeting rice production in China. But many years before, they were found to be ruining sugar crops in Australia.

Currently, the Southern Rice Black-Streaked Dwarf Virus is transferred by the White-Backed Planthopper and causes damage to rice crops. The earlier the plant is infected, the more damage that is done.

Similar to the other diseases we’ve reviewed today, this virus can cause dwarfing, stiffening of leaves, lack of grain production, and increased tillering. The infected plant leaves are often dark and short with some ruffling on the edges.

Like so many other diseases, every component of its management can potentially affect its neighbor. As we’ve seen in recent months, all it takes is one vector to carry disease to a new environment and create a dramatic impact. Habitats and ecosystems may vary from place to place, but many of these species are genetically designed to thrive on its unsuspecting victims.

How It Affects You

As we come to a close with our examinations of viruses, we hope that this has made you more curious and considerate of how viruses can infect our world. Where we once thought viruses to be limited, maybe now we’re a little more open-minded on just how easily they can spread. As the world reemerges from its quarantine cocoon, we recognize that our perception of viruses has changed, hopefully for the better.

At Plant Sentry we plan to use our new-found knowledge to help our growers achieve optimal plant health. We work around the clock to provide our clients with the highest level of awareness against disease and pests. Through our expertise in disease management we know the best practices that will make work easier on growers for seasons to come. In this ever-changing world, there has never been a better time to do the right thing and keep your plants safe and healthy. To learn more about our practices visit the Our Services page and see why what we’re doing makes a BIG difference.

VIRUSES & VIRAL PLANTS Pt. 2

Last week we shared a brief introduction with you about three rare virus families. What makes these virus families so unique is their ability to infect humans, animals, and plants.

Out of 23 virus families, only 3 of them can cross between the Animalia and Plantae Kingdoms!

We looked at the Bunyaviridae family first and discovered that it is responsible for the Tospovirus, which is commonly seen in Thrips and can quickly cause stunted growth in important plants.

This week we’d like to take a closer look at the Rhabdoviridae virus family.

RHABDOVIRIDAE

The Basics

The Rhabdoviridae virus family officially contains 20 genera and has 143(4) species that are negative-sense and consist of a single-strand RNA. While the family of viruses can be hosted by vertebrates, arthropods, and plants, many of the plant and vertebrae viruses are arthropod-borne.

Out of the 20 genera that exist in this viral family there are 2 that are most commonly known to humans worldwide. As I’m sure you could guess by the name, one of the most infamous viruses of this family is Rabies. This virus may seem confined to only animals in developed portions of the world. But, in the countries of India and Africa, this virus remains a serious threat to humans. There are vaccines and antibodies to combat the virus, but don’t be fooled! If left untreated the disease has a 100% chance of death.

The second most notorious virus of this family is vesicular stomatitis. This disease affects horses, cows, sheep, pigs, goats, llamas, alpacas, and occasionally humans. The result of contracting this virus is an influenza-like illness. While this virus may not be as severe as the Rabies virus, it still has an important economic impact on countries like the United States, who have eradicated similar diseases.

Affect on Plants

Now that you’ve seen the terror that this family of viruses can have on humans and animals, how does it affect plants? Well, I’m glad we finally got to this point.

There are 4 different genera of this viral family that infiltrate plants: Cytorhabdovirus, Dichorhavirus, Nucleorhabdovirus, and Varicosavirus.

Cytorhabdorvirus

This genus of viruses is commonly spread through arthropod vectors such as aphids, leafhoppers, and planthoppers. In 2015 a Novel Cytorhabdovirus was found in rice plants in China. The result of infection was dwarfing, yellow striping of leaves, mosaic and twisting of leaves, and eventually production of inferior heads of the plant bearing mostly few and unfilled grains. Typical symptoms of varieties of this virus in other plants include yellow striping, mosaic, and twisting of the leaves.

Dichorhavirus

This genus of the Rhabdoviridae virus is typically transmitted by mites. These viruses generate symptoms of localized lesions on leaves, stems, and fruits of plants that have high economical value. These viruses most commonly affect citrus, coffee, and orchids. Between 2013 to 2016 a new Citrus leprosis virus was discovered in Brazil. Citrus leprosis (CL) is a viral disease that produces necrotic and chlorotic lesions on the leaves, branches, and fruit of the citrus plant. This disease causes a significant yield reduction in citrus orchards. Additional diseases that are commonly seen from this virus also include Orchid Fleck Virus (OFV) and Coffee Ringspot Virus (CRV).

Nucleorhabdovirus

This genus of viruses is transmitted commonly by leafhoppers, planthoppers, and aphids but can also be spread through vegetation propagation and mechanical measures. One of the most well-known variations of this virus is the Maize Mosaic Virus (MMV). This disease has been infiltrating plants since 1960. But in more modern times, there are many new varieties coming to light. In 2010, an alfalfa plant located in Stadl-Paura, Austria displayed symptoms of viral infection. In 2018 and 2019 the virally infected plants have been evaluated by scientists and have identified a new novel Nucleorhabdovirus strain. It is proposed as Alfalfa-associated Nucleorhabdovirus (AaNV). The disease can cause leaf rolling, mottling, yellowing, curling, and chlorotic lesions.

Varicosavirus

This genus naturally occurs in two families of plants: Compositae (which largely contain Angiosperms or flowering plants) and Solanaceae (which contain nightshade or potato family of flowering plants). The diseases of this genera are traditionally spread through soil and hydroponic systems by zoospores of a fungus called Olpidium virulentus. The two most common diseases associated with this viral genus is the Mirafiori Lettuce Big-Vein virus (MLBVV) and the Lettuce Big-Vein associated Virus (LBVaV). The LBVaV has been reported in many parts of the world including the United States and Europe. As of 2015 LBVaV infected lettuce plants have been observed in the central region of Columbia. The infected plants exhibit symptoms of vein clearing, big vein (hence the name), ruffling of the edges of the outer leaves, and small to no head.

What Does This All Mean?

While many of the viruses mentioned may originate somewhere else in the world. The impact each of these diseases has on the United States shouldn’t go unnoticed. Many of these diseases and pests are seen here in the United States because of the lack of diligence from outside countries.

Plant diseases and pests wreak havoc on our agriculture and threaten our environment, food, and jobs!

Amidst the current pandemic, the Plant Industry maintains a firm ground in the economy as people look to bring the outdoors inside. With mandated quarantines and economic decline, many people have looked to invest in their surroundings instead of their experiences.

This steady stream of potential has forced many in-store only sellers to take-on the e-commerce approach. While it may sound “hunky-dory”, many of these companies are inexperienced when it comes to selling across state lines, and do not realize the risks to our homes, gardens, and environment.

Companies that aren’t using Plant Sentry, may not be protecting your plants!

Plant Sentry works around the clock to protect plants, YOUR plants. Growers that use Plant Sentry say to their buyers, “We’ve done our part to protect these plants from disease, pests, and invasive species so you can do your part in caring for them.”

So when you’re reemerging from your quarantine and looking to improve your landscape, look for the Plant Sentry seal of verification and know that we’ve done our part so you can enjoy yours!

If you’re interested in learning how to protect your plants Contact Us today!

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