Pular para o conteúdo principal

New way to detect Palmer amaranth in contaminated seedlots

The new genetic test can detect a single Palmer amaranth seed among 99+ seeds of close relatives.
Credit: Lauren D. Quinn
Last summer, farmers in the Midwest got an unwelcome surprise after planting native seed on Conservation Reserve Program acres. Palmer amaranth, the aggressive and hard-to-kill weed, had established in droves. As a possible solution, some states declared Palmer a noxious weed, which prohibits its sale and transport.

"I've had seed growers call me," says Pat Tranel, molecular weed scientist in the crop sciences department at the University of Illinois. "Their businesses are up in the air because of this. Unless they have a way to certify their product is Palmer-free, they can't sell it."

The typical testing method involves growing a sample of seeds until the plants are large enough to be identified, but this is a slow and potentially unreliable process.

"It all takes a long time, and sometimes the seeds don't germinate during the test," Tranel says. "Alternatively, there's a company that will test individual seeds using DNA sequencing, but they're charging $100 per seed. It's not cost-effective."

Tranel and graduate student Brent Murphy developed a way around these issues. Their low-cost method can identify Palmer amaranth DNA from within a mixed sample without having to grow the plants. The assay, which uses a method known as quantitative PCR, can detect genetic variations unique to Palmer even when flooded with samples from closely related species, including waterhemp.

"Palmer, redroot pigweed, waterhemp -- they all have tiny black seeds that basically look the same. We needed a way to efficiently extract DNA from pooled seed samples and, if it's present, identify Palmer," Tranel says.

Once Tranel and Murphy developed this assay, they worked with U of I Extension's Plant Clinic to optimize the test for mixed seed samples. Diagnostic outreach Extension specialist Diane Plewa and Plant Clinic technician Elizabeth Phillippi began trying different methods to extract DNA from seed. The assay is very sensitive, but if DNA is not correctly extracted from a lone Palmer amaranth seed in a mixed sample, it won't be detected.

"The trick," Plewa says, "is to make sure every seed is ground up during the extraction process."

The researchers were able to consistently detect a single Palmer amaranth seed when mixed with 99 waterhemp seeds, and they believe the assay could achieve even greater sensitivity with additional refinement.

The Plant Clinic has optimized a protocol for commercial testing of seed lots. "We have a test that we feel very confident in," Plewa says. "We are offering the service now, for $50 per sample." For more information, call 217-649-3941 or visit the Plant Clinic website.

Source: https://www.sciencedaily.com/releases/2017/06/170606112735.htm

Postado por David Araripe

Comentários

Postagens mais visitadas deste blog

CONSERVAÇÃO DE ALIMENTOS E A EQUAÇÃO DE ARRHENIUS por Carlos Bravo Diaz, Universidade de Vigo, Espanha

Traduzido por Natanael F. França Rocha, Florianópolis, Brasil  A conservação de alimentos sempre foi uma das principais preocupações do ser humano. Conhecemos, já há bastante tempo, formas de armazenar cereais e também a utilização de azeite para evitar o contato do alimento com o oxigênio do ar e minimizar sua oxidação. Neste blog, podemos encontrar diversos ensaios sobre os métodos tradicionais de conservação de alimentos. Com o passar do tempo, os alimentos sofrem alterações que resultam em variações em diferentes parâmetros que vão definir sua "qualidade". Por exemplo, podem sofrer reações químicas (oxidação lipídica, Maillard, etc.) e bioquímicas (escurecimento enzimático, lipólise, etc.), microbianas (que podem ser úteis, por exemplo a fermentação, ou indesejáveis caso haja crescimento de agentes patogênicos) e por alterações físicas (coalescência, agregação, etc.). Vamos observar agora a tabela abaixo sobre a conservação de alimentos. Por que usamo...

Two new proteins connected to plant development discovered by scientists

The discovery in the model plant Arabidopsis of two new proteins, RICE1 and RICE2, could lead to better ways to regulate plant structure and the ability to resist crop stresses such as drought, and ultimately to improve agricultural productivity, according to researchers at Texas A&M AgriLife Research. Credit: Graphic courtesy of Dr. Xiuren Zhang, Texas A&M AgriLife Research The discovery of two new proteins could lead to better ways to regulate plant structure and the ability to resist crop stresses such as drought, thus improving agriculture productivity, according to researchers at Texas A&M AgriLife Research. The two proteins, named RICE1 and RICE2, are described in the May issue of the journal eLife, based on the work of Dr. Xiuren Zhang, AgriLife Research biochemist in College Station. Zhang explained that DNA contains all the information needed to build a body, and molecules of RNA take that how-to information to the sites in the cell where they can be used...

Fármaco brasileiro aprovado nos Estados Unidos

  Em fotomicrografia, um macho de Schistosoma mansoni, causador da esquistossomose CDC/G. Healy A agência que regula a produção de alimentos e medicamentos dos Estados Unidos, a FDA, concedeu o status de orphan drug para o fármaco imunomodulador P-Mapa, desenvolvido pela rede de pesquisa Farmabrasilis, para uso no tratamento de esquistossomose.  A concessão desse status é uma forma de o governo norte-americano incentivar o desenvolvimento de medicamentos para doenças com mercado restrito, com uma prevalência de até 200 mil pessoas nos Estados Unidos, embora em outros países possa ser maior. Globalmente, a esquistossomose é uma das principais doenças negligenciadas, que atinge cerca de 200 milhões de pessoas no mundo e cerca de 7 milhões no Brasil.  Entre outros benefícios, o status de orphan drug confere facilidades para a realização de ensaios clínicos, após os quais, se bem-sucedidos, o fármaco poderá ser registrado e distribuído nos Estados Unidos, no Brasil e em outro...