broomrape, a highly infectious parasitic plant in the Solanaceae, spreads quickly, and once it is parasitized to the tomato field, the tomato is basically extinct. The parasitic plant has been found in tomato fields in southern Xinjiang for many years.
Look at the properties of Ledan
The genus Orobanche is derived from the Greek words erobos (bitter vetpea) and ancho (strangulation, strangulation), and the epithet coerulescens means "blue". [3]
Biennial herb, 15 cm to 40 cm tall (up to 50 cm), chlorophyll-free, yellow-brown, densely coated; Stem simple erect; Lanceolate leaves alternate, degenerate into scales, ca. 2 cm long; Inflorescence densely spicate on upper stem, 10 cm to 20 cm, bracts very similar to leaves; Calyx divided into two parts, split near base, each part divided again, all lobes lanceolate; Summer flowers, corolla dark blue, blue purple, lavender, yellow; Flower tube constricted, with two lips, upper lip with two petals; Filaments with long soft hairs, style usually glabrous, about as long as filaments; Stigma bifid; Capsule ovate-oval, with many seeds, ca. 0.3 mm long. Chromosome 2n = 38.
It is often parasitic on the roots of Artemisia plants.
distribution
It grows on slopes and grasslands from 900 meters to 4000 meters above sea level.
Japan, South Korea, Russia, Mongolia, Kazakhstan, Turkmenistan, Kyrgyzstan, Nepal, and Europe.
Distribution in China: Gansu, Hebei, Heilongjiang, Hubei, Jilin, Liaoning, Inner Mongolia, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Tibet, Yunnan.
The yellow to white species (some scholars believe that its scientific name is f. korshinskyi(type) or var. albiflora (white flower variety)) are distributed in Russia, Mongolia, Europe and other places, while China is found in Gansu, Hebei, Heilongjiang, Liaoning, Inner Mongolia.
California Tomato Institute: Study of Arabidopsis brachycarpus
March 29, 2024 - Francois -
Professor Xavier Bronthom studies the genetic secrets of invasive weeds that threaten the $1.5 billion tomato industry. Adam Schneider is investigating the root causes of a parasitic weed that has the potential to wreak havoc on California's 11 million ton processed tomato industry.
Schneider, an assistant professor of biology at the University of Wisconsin-La Crosse, received a $52,268 research grant from the California Tomato Institute to study genetic material in the branchy stem, an invasive weed of high concern in the California Department of Agriculture. Although the branched short stem looks like a delicate purple flower on the outside, it is a threat in tomato fields where its seeds grow to the roots of the host plant and suck up nutrients. The problem is particularly acute in California, where 95 percent of processed tomatoes in the United States are grown. The weed, which is native to Eurasia but was first discovered in the United States in 1890, can reduce crop yields by up to 80 percent, resulting in huge costs for farmers and state governments. The weed has appeared intermittently in California tomato crops over the past century - sometimes not reported for decades.
But in more recent outbreaks in 2009, 2014 and 2017-23, the weed has left farmers and policymakers baffled as to how to eliminate the plant altogether. Schneider has spent the past two years studying the genetic variation in the branched brachycarpus, or Arabidopsis lamosha as it is scientifically known. Just as any population of a given species, be it giraffes or maples, has slight differences in characteristics within its species, so does this weed. If Schneider can use these slight differences to identify some unique genetic subpopulations of the branched brachycarpous stem, those subpopulations may provide clues about how it persists and evades mitigation efforts for more than a century.
The key question in Schneider's mind is whether the current branched-stem outbreak is a modern revival of an earlier outbreak, or whether it was reintroduced to California via contaminated seeds from other countries. Such knowledge can help determine the best management strategies to control the spread, whether it's improving agricultural health practices in California or tightening controls on seed imports. "Whatever I find, the data will help make better management decisions," Schneider said. "The direct economic and human benefits are motivating to me personally and complement other ongoing research projects in my lab that focus on native plant species." According to Schneider's previous research, funded by the California Tomato Institute, there are no significant genetic differences within the species so far, meaning that despite the time lag between infected fields, all outbreaks may have originated from the same original seed introduction.
In other words, there is currently no support for the hypothesis that seeds were reintroduced to California from out of state. But with the updated grant, Schneider can study the current outbreak more fully and expand his sample size by adding new locations in California and internationally in 2023 and 2024, thereby improving the validity of those results. Specifically, the new grant aims to compare a previously unstudied population of branched brachystems in Chile with a population in California.
Genetic data was added from seven newly infected fields in California in 2023 or 2024 to determine whether the samples had characteristics seen in other parts of the state and region. Determine whether published data on several Eurasian branchial stem populations on different hosts can be analyzed together with existing California data sets. To understand the plant's genetic makeup, Schneider and his research team used a machine with steel balls so they could grind individual flowers of the parasitic plant into small pieces in order to extract DNA and purify it. The sample is then sent to a specialized DNA analysis lab on another campus. Their research will look at 13 different genes in the genome of the branchial stem. These 13 genes have the right level of variation so that differences within species can be detected, a fact that was validated by a UWL Molecular biology class earlier this year.
In addition to the California Tomato Institute grant, Schneider has been awarded a UWL faculty research grant that will allow him to analyze samples of branched-short stems from across the United States. Taxonomists speculate that the branched short-stemmed stems consist of two distinct species, one of which is more of a threat to the crop. He will compare the genetic material in samples of affected pathogens in California with samples from other parts of the United States (non-agricultural farms) to determine if they are the same species. These dried samples of branched stems will be crushed in a grinder to extract DNA.
Why is this weed so common?
Several ways in which the branched stems are established make them particularly difficult to detect. Almost all of its plant-destroying advances occur underground. By the time it can be detected on the ground, the plant has been established. In addition, the maximum height of the plant is still low, making it nearly impossible to find in tomato fields. Each branch short-stemmed flower can produce tens of thousands of seeds, smaller than a fine ground pepper, meaning it can spread quickly. California already has strict controls in place. Even if there is a report on the plant, the entire tomato crop will need to be destroyed, and susceptible crops cannot be grown in the space for two years. This results in low reporting rates among farmers.
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