Menu

New Approach to Studying Fungus’ Attack on Soybeans

A new laboratory technique developed by Agricultural Research Service (ARS) scientists could speed the search for soybean plants with resistance to the fungus that causes Phomopsis seed decay (PSD) in the legume crop.

A disease primarily caused by the fungus Phomopsis longicolla, PSD physically degrades soybean seed and reduces the quality of its protein and oil. In 2012, outbreaks of PSD and other fungal diseases cost soybean producers in 16 southern states more than 2 million bushels in losses.

Applying fungicides, rotating soybeans with nonhost crops and tilling the soil are among strategies used by growers to prevent PSD. However, breeding for resistance to PSD is the most effective long-term strategy, according to Shuxian Li, a plant pathologist with the ARS Crop Genetics Research Unit in Stoneville, Mississippi.

As part of a Phomopsis resistance program there, Li has sought to learn more about how the fungus inflicts harm at the cellular level. Towards that end, she and colleagues enlisted the aid of Agrobacterium tumefaciens, a species of soil bacteria commonly used in genetic engineering procedures to endow plants with new traits.

In this instance, the team used the bacterium to “shuttle” genes for an antibiotic marker and green fluorescent protein (GFP) into the nucleus of the fungus’ cells. This resulted in new P. longicolla strains that produce the protein and emit a green glow when exposed to light in the blue-to-ultraviolet range.

Li plans on inoculating soybean seedlings with the modified strains to study how the infection process unfolds within the tissues of both resistant and susceptible soybean germplasm lines. The approach should also facilitate the identification of sources of PSD resistance that may escape detection using conventional disease-screening methods, such as those requiring field observation of symptoms.

Source: Jan Suszkiw, Agricultural Research magazine 

Recent News

If you Have Not Been Scouting Corn, Now Is the Time to Start
7/14/2020

Most of Illinois this season has been hot and dry, especially through central and northern portions of the state .  This has been good as far as limiting foliar diseases in our corn crop.  Fungi require some level of moisture for spores to germinate, and the fungus to grow and infect foliage.  This is a major reason […]

Soybean Demand Linked to Economic Recovery
7/14/2020

Wet and warm conditions over some key soybean growing regions pressured soybean prices recently.  The prospect of a good soybean crop places added emphasis on demand over the next year.  Soybean consumption in 2020-21 shows a substantial increase driven mostly by expanded exports in the recent WASDE report.  A robust recovery in domestic and world […]

Western Corn Rootworm Beetles Emerging, Time to Scout
7/13/2020

Western corn rootworm beetles began emerging in southeast and south central Nebraska at the end of June. Beetles typically emerge somewhat later in northeastern and western Nebraska. Beetles emerging before silk emergence may feed on corn leaves. They feed by scraping the surface tissue, leaving a white parchment-like appearance. Once silks emerge, they become the […]

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now