Research

Sword’s research plays key role in new technology poised to make major cotton industry contribution

August 3, 2016 by Rob Williams

by Steve Byrns, Texas A&M AgriLife Communications

COLLEGE STATION—The dream of many Texas cotton farmers plagued by dwindling irrigation water and drought might be to someday produce more fiber using the same amount of water.

That dream is fast becoming reality now thanks to a commercially available seed treatment from Indigo Ag called Indigo™ Cotton. The science behind the treatment stems directly from research started by Dr. Greg Sword, a Texas A&M entomologist.

But the dream gets better.

Sword and Indigo-his industry partner-say that under some conditions the production or yield can be as much as 10 percent higher than untreated crops and needs no special crop management inputs beyond a simple endophyte microbial coating of the planting seed.

Endophytes are microbes that can live inside plants, analogous to the microbes that live inside humans and play important roles in human health.

Students working in the field — Sword Lab students working in the field. Photo by Cesar Valencia.

That means no specialized farming equipment is required, no genetically modified organism technology is associated with the process, no more acreage is taken into account, there’s no need for increased planting rates, and no additional pesticides or fertilizer applications need be applied over what’s normally used, Sword said.

In fact, Sword’s lab has shown that some endophytes can reduce pest pressure on cotton as well. In short, the process means more profit for the producer with no added stress on the environment.

“As an entomologist, my first research initially focused on the important effects microbes could have in conferring resistance in cotton to insects and nematodes and potentially affect cotton yields in that way,” Sword said. “But I also started to suspect that water stress was involved, and we conducted field trials showing increased yields were possible. This is what started getting the early attention from industry in 2012-2013.”

Now, there are 50,000 acres planted with the Indigo™ Cotton treated with a microbe from Sword’s lab – most of it in the High Plains of Texas. This part of Texas, often called “The World’s Largest Cotton Patch,” is the most intense area of cotton production in the U.S. and sits over the huge, but slowly dwindling Ogallala Aquifer.

In 2013, Texas A&M AgriLife Research, with assistance from Texas A&M Technology Commercialization, inked an exclusive licensing deal with Indigo to have the rights to commercialize the fungal endophytes that Sword’s lab collected from cotton.

“Through joint research with Indigo, we began to find that many of the microbes I collected were also having effects in conferring water stress resistance,” Sword said.

Sword said that it was his early work that clearly showed the microbes could be applied to seeds that could then be planted under normal field conditions with observable effects on plant performance and yields.

Indigo has raised close to $156 million in private investment funding so far, with $100 million of that from the most recent round of fundraising, as noted by reports in the media, Sword said.

“That made a big splash because it was the largest private equity fundraising effort ever in the agricultural technology sector to date,” Sword said. “So not only are the ag people paying attention now, but so are the finance/Wall Street types.

“Although Indigo’s first product is in cotton and based on a microbe from my lab, they have lots of other developments going on with other microbes in other crops,” Sword said. “But the cotton data was promising enough that it led to their first commercial offering being for cotton, and the strength of the cotton data surely helped them convince investors to invest. So it’s not exclusively due to the cotton data, but it definitely helped.”

So why should non-farmers care?

“Because producing more food and fiber with less water, or even producing the same amount with less water, is a critical global need as water becomes scarce and droughts become more common and widespread,” Sword said. “It is my hope that our partnership with Indigo is a strong start to a new kind of green revolution, where considerably more food and fiber can be produced without further taxing the water supply or environment.”

Grad Student Assists In Rediscovery of Grasshopper Species Not Seen in Almost 60 Years

July 12, 2016 by Rob Williams

Melanoplus foxi - live male — A live *Melanoplus foxi* grasshopper on a leaf. Photo by Derek Woller

For almost 60 years, scientists thought that Melanoplus foxi Hebard, 1923, a flightless grasshopper endemic to Georgia, was possibly extinct until Ph.D. student Derek Woller and Assistant Research Professor JoVonn Hill at Mississippi State University recently re-discovered the species in May of 2015 after nine years of active searching.

Woller became aware of the species in the first place because, for his dissertation, he is examining the evolutionary history of the 24 species that make up the Puer Group (Acrididae: Melanoplinae), which includes M. foxi. He said that inroads towards finally rediscovering the species came about when he needed to collect fresh specimens to extract DNA from in order to finish reconstructing a phylogenetic tree for the group.

Members of the Puer Group are very small and have tiny wings, but are flightless. The grasshoppers are mainly located in the southeastern United States and are associated with xeric habitats, which are habitats that lack moisture.

“There are many reasons why this species flew under the radar for so long, the primary reason being that they are quite difficult to find unless you’re actively looking for them. But, habitat degradation also played a significant role,” Woller said.

A modern county map of Georgia overlaid with historical and current georeferenced data of the <em>Melanoplus foxi <em>species. Photo by Derek Woller. — A modern county map of Georgia overlaid with historical and current georeferenced data of the *Melanoplus foxi* *species. Photo by Derek Woller.*

According to the publication, much of Georgia’s habitat has been changed from historically large areas of longleaf pine forests to mostly agricultural and urban landscapes, which has possibly led to the decline of the species over the years.

Woller said they searched for any sign of the species at more than 101 unique sites across Georgia with no luck, including four that contained M. foxi in the past according to the locality data from museum specimens.

Additionally, prior to its rediscovery, only four U.S. collections (University of Michigan Museum of Zoology’s Insect Division, the Academy of Natural Sciences of Drexel University, the Florida State Collection of Arthropods, and the North Carolina State University Insect Museum) possessed specimens of the species, and only 35 specimens in total.

During his dissertation research, Woller discovered that there were actually 71 more specimens of M. foxi hidden away in a drawer of unidentified grasshoppers in Michigan’s museum collection. The locality data on the specimens were linked to the field notes of three scientists from Michigan who collected grasshoppers, along with many other insects, in Georgia in the fifties.

Woller said most of the detailed notes described all new locations to search in within a single county in Georgia near the Spring Creek area, but he and Hill had a difficult time relating these locations with modern-day maps.

However, the breakthrough came when a historical map loaned from the Georgia Department of Natural Resources helped them translate the original sites into modern locations. The dates on the notes also suggested that searching within June and July might yield the best results.

Once they knew where to look specifically and when, they headed into the field in May of 2015 and were finally successful, finding many nymphs and a few young adults.

“As it turns out, the main reason this species is so hard to find is that it appears to be mainly active in late spring and summer, and then it dies out quickly,” Woller said. “This is an excellent reason why it pays to try to understand the life history of organisms of interest and why it’s important to have good specimen representation of a species in a museum.”

The new label data from the museum specimens and field notes led to two other re-discoveries, both further northeast from the first point of rediscovery (and on the same trip): one within a state park and one in roadside habitat that was seemingly left untouched for almost 60 years.

“Other difficult-to-find and possibly-extinct species benefit from a success such as ours because, first and foremost, it brings hope for more successes,” Woller said. “Also, our rediscovery truly demonstrates the importance of museum specimens and their associated field locality data because, without them, we may have been still out there searching for M. foxi, just like the classic needle in a haystack.”

The publication can be found at the ResearchGate website at: https://www.researchgate.net/publication/292722433_Melanoplus_foxi_Hebard_1923_Orthoptera_Acrididae_Melanoplinae_Rediscovered_After_Almost_60_Years_Using_Historical_Field_Notes_Connected_to_Curated_Specimens

New discovery may improve future mosquito control

June 13, 2016 by Rob Williams

AgriLife Research scientist’s paper outlines a new mechanism of sugar feeding aversion

By: Steve Byrns, Texas A&M AgriLife Communications

Aedes aegypti females reject the sucrose solution containing the synthetic peptide. The sugary solution contained a blue dye to trace the meal in their gut. (Photo courtesy Dr. Patricia Pietrantonio, Texas A&M AgriLife Research Fellow) — *Aedes aegypti* females reject the sucrose solution containing the synthetic peptide. The sugary solution contained a blue dye to trace the meal in their gut. (Photo courtesy Dr. Patricia Pietrantonio, Texas A&M AgriLife Research Fellow)

COLLEGE STATION – Major rainfall across most of Texas triggering hordes of mosquitoes coupled with seemingly constant mosquito-related Zika virus media reports from around the globe may have set the stage perfectly for what one researcher deems as a very significant discovery in man’s war against earth’s leading human disease carrier.

Dr. David Ragsdale, head of the entomology department at Texas A&M University, College Station, credits Dr. Patricia Pietrantonio, a Texas A&M AgriLife Research Fellow in the entomology department at College Station, along with her students and colleagues from other institutions, with discovering a receptor on the legs of mosquitoes that when activated, keeps female mosquitoes from taking a sugar meal and makes them fly away.

“This finding could lead to novel mosquito repellents,” Ragsdale said. “This is really a big deal, a major achievement.”

Ragsdale said Pietrantonio has just had the article, “Leucokinin mimetic elicits aversive behavior in mosquito Aedes aegypti (L.) and inhibits the sugar taste neuron,” on the work published in the Proceedings of the National Academy of Sciences. To view the work and its authors go to http://www.pnas.org/content/early/2016/06/01/1520404113.abstract.

“What makes this even more compelling is the work was with Aedes aegypti, the mosquito species responsible for spreading Zika, dengue, yellow fever and Chikungunya viruses,” Ragsdale said. “This work is the culmination of over five years of study by Dr. Pietrantonio, her students and collaborators. With Zika a looming threat, this is a timely discovery.”

Pietrantonio said after mating, Aedes aegypti females immediately search for a blood meal from a human host.

“They are highly anthropophilic, meaning they are attracted to humans,” Pietrantonio said. “They may even follow people indoors. If female mosquitoes are infected with viruses they may transmit them to humans when they acquire a blood meal.”

The blood meal supplies the protein source female mosquitoes require to produce eggs, she said.

“However, in the field, if human hosts are not present, females will feed on sucrose solutions such as nectar from flowers, though they prefer a blood meal to a sugar meal but male mosquitoes feed only on nectar. Certainly sugar feeding is one of the two feeding modalities for adults of this species.”

“We found that a synthetic peptide that was designed to mimic a peptide naturally present in mosquitoes triggers an aversive fly away, walk away or jump away behavior in female mosquitoes.”

If the same aversion could be tied to a blood meal, she said a totally new and effective mosquito feeding deterrent may be in the offing, one that perhaps would cause the mosquito to pass up the required blood meal needed to lay eggs. Doing so would either disrupt the life cycle and/or reduce disease transmission.

However, this is far from being accomplished, she said.

“One of our team designed a peptide mimetic of the kinin peptides, which are diuretic hormones in mosquitoes, to be resistant to enzymatic degradation,” Pietrantonio said. “These mimetics are more potent than those found naturally, because they take longer to be degraded by the insect. These diuretic hormones make mosquitoes lose water after a blood meal, but we also found the peptidomimetic blocked sugar perception. This is a completely new and unexpected discovery.”

The research team localized these receptors in the feet and mouthparts of mosquitoes. What is really new, they said, is that this type of receptor proteins known as GPCRs, were not previously considered to be important for “taste” in insects and further, contact with the peptidomimetic made the mosquitoes fly away.

“In sum, we unequivocally verified this kinin receptor is present in the taste organs of the legs and labella, the pair of lobes at the tip of the proboscis.”

Pietrantonio said their observation that the peptide blocks sugar perception is interesting because the peptide is insect-specific, therefore, the receptor represents a target for further applied research to find ways to diminish the ability of female mosquitoes to feed. Doing so would likely reduce their lifespan or reproductive capacity.

“We had a lot of fun doing this research within the frame of an international, multi-institutional and multidisciplinary collaboration,” she said.

Institutions involved along with Texas A&M were the U.S. Department of Agriculture-Agriculture Research Service, Iowa State University and Université Paris-Saclay, France.

Pietrantonio said the team will continue to study the system in the hope of developing an effective mosquito feeding deterrent in order to stop what is arguably the greatest foe to mankind on earth.

Retired Researcher’s Decades of Work on Texas Spiders Published

May 23, 2016 by Rob Williams

Allen Dean standing with a specimen from his collection. Photo by Rob Williams.

Former research assistant Allen Dean has turned an interest in learning about spiders into a decades-long effort to catalog all spider species of Texas. Recently, these records were turned into a 700-page catalogue of Texas spiders that was recently published online.

This paper, titled “Catalogue of Texas Spiders,” is the end result of the work of several decades of collecting and researching on various spider species statewide, as well as literature reviews from other publications that were published decades ago.

The catalog contains a list of 1,072 species in 53 families and includes the species, its distribution and locality, habitat, collecting method and notes about each species with an extensive reference section.

Some of the more notable numbers of species collected and recorded include340 species recorded in Hidalgo County, 323 in Brazos County, and 314 in Travis County. In addition, several endangered species from two families, Dictynidae and Leptonetidae, are listed.

Dean first started working with spiders in 1977 when Dr. Winfield Sterling wanted to study the role of spiders as predators in cotton agroecosystems even though he knew little about spiders. He started collaborating with Dr. Norman Horner at Midwestern State University to help with identifications.

Although only very limited lists of spider species were available when he began the project, Dean wanted to expand on previous works published by Bea Vogel and B.J. Kaston, as well as other authors that have recorded species from Texas.

He then started keeping track of Texas spiders for the publication beginning around 1980. He added information from various sources of information, including previously published papers, the spider collections at Texas A&M University and other institutions, and his own collection.

Dean also had help from the Texas A&M Insect Collection curator Dr. John Oswald, former Associate Curator Ed Riley and Curator Emeritus Horace Burke as they allowed him access to and support for expanding the collection. “Ed traveled extensively collecting insects and spiders that added many additional records,” Dean said. “The insect and spider collection at TAMU continues to grow. We currently have about 20,000 vials of spiders from Texas, United States, Mexico, and other countries.”

Dean was, additionally, a resource for students needing to identify spiders for their research projects and also cooperated with several scientists statewide. He said that these collections done by graduate students, staff and faculty have helped immensely with expanding the collection at TAMU.

Dr. Marvin Harris had worked with Dean for more than 30 years on various projects with his lab and when Sterling was leading the cotton entomology program. Harris said that spiders do play a very important role in several agroecosystems in the state, including pecans.

“His work in the Pecan Insect Lab at Texas A&M University involved numerous students over 30+ years and also caused me to rethink the role spiders play in the pecan agroecosystem,” Harris said. “My current view is that they constitute a very robust first line of biocontrol and are largely responsible for the maintenance of endemicity of insectan herbivores in most places most of the time.”

Harris added that the publication will help expand knowledge of spiders’ roles in other agroecosystems.

“This publication will allow such ideas, as well as many others, to be tested in ecosystems and agroecosystems throughout the state. Allen Dean’s decades-long effort documents an increase in 50% of the genera and 100% of the species of spiders that are now known to occur in Texas,” Harris said. “The publication is chock full of information in addition to species identifications. This is now the most important reference on spiders of Texas and will be useful to experts world-wide that study spiders and to non-specialists that study arthropod complexes that wish to include studies of spiders.”

AgriLife Research entomologist testing potato psyllids for insecticide resistance

May 5, 2016 by Rob Williams

by Kay Ledbetter, Texas A&M AgriLife Communications

Dr. Ada Szczepaniec, Texas A&M AgriLife Research entomologist, examines psyllid activity. (Texas A&M AgriLife Communications photo by Kay Ledbetter)

AMARILLO – A growing resistance of potato psyllids to the neonicotinoid classification of insecticides has Dr. Ada Szczepaniec, Texas A&M AgriLife Research entomologist in Amarillo, looking to the future.

The potato psyllid is a tiny insect with sucking, piercing mouthparts that transmits a disease called zebra chip and can cause tremendous losses to producers, Szczepaniec said. Producers have used the neonicotinoid insecticides to protect their solanaceous crops, mostly potatoes, in the past.

The problem, she said, is many of these psyllids migrate from Mexico up into the Rio Grande Valley, and Mexico does not have as stringent of application regulations as the U.S. The aggressive use of the product in Mexico has allowed the psyllids to develop a resistance over time to the insecticide.

Pysllids of all ages cover a tomato plant in Dr. Ada Szczepaniec’s greenhouse study. (Texas A&M AgriLife Communication photo by Kay Ledbetter)

“It only takes a few psyllids to cause tremendous losses to a crop because they do not need to feed for a prolonged period of time to transmit the disease,” Szczepaniec said.

The disease causes the starches in the potato, when fried as a chip or French fry, to harden and turn dark brown, causing the zebra chip pattern that makes the food product look unappealing and taste bitter, she said.

“We are trying to figure out is how to control the psyllids,” Szczepaniec said. “The biggest potato-producing region in Texas is of course the Rio Grande Valley. So some of these psyllids come up from Mexico into the Valley and when the production of potatoes and tomatoes ends in the Valley, they keep moving up north.”

They arrive in the Texas Wintergarden area and then move north into the Panhandle, she said. Additionally, there are probably some populations overwintering in each location as well.

Szczepaniec is collecting potato psyllids from all the major potato-producing regions of Texas and testing them in her greenhouse to see if they are still susceptible to the neonicotinoid insecticides.

“We maintain these psyllid colonies on tomato plants and then expose plants to the insecticide as they would be treated in the field. We then move the immature psyllids onto the plants and measure their survival.

Damage to tomato plants from psyllids can be seen in the insecticide study by Dr. Ada Szczepaniec, Texas A&M AgriLife Research entomologist in Amarillo. (Texas A&M AgriLife Communications photo by Kay Ledbetter)

“That allows us to figure out if they are still effectively suppressed by the insecticides,” she said. “What we are looking for is close to 100 percent mortality, because the psyllids feed on the plant continually, but only have to feed for a very short time before transmitting the disease.”

When the neonicotinoids work, they work really well, Szczepaniec said. They can be used during planting and are taken up by the plant and present inside the plant tissue. So when the insects feed on plants treated with the insecticide, they die. There are some formulations of these insecticides that can be sprayed onto the crop after it emerges as well.

“It’s been a great control measure and suppressed the psyllids very well,” she said. “However, there have been reports, especially in the Valley, that some populations of psyllids are no longer effectively controlled by these insecticides. This has not been confirmed experimentally until now, and this is one of the priorities of our research program.”

Szczepaniec said she will be testing other insecticides as well once it is determined which populations are no longer susceptible to the neonicotinoids.

“We want to figure out what producers can use if neonicotinoids are no longer effective in their region,” she said. “We will continue the testing and collection over several years in order to provide producers with customized combinations for their regions where we collected the psyllids and help them manage them successfully.”