Transcriptome sequencing identifies novel persistent viruses in herbicide resistant wild-grasses

Area of Science:

• Plant Pathology
• Weed Science
• Molecular Biology

Background:

• Herbicide resistance in UK wild grasses, particularly non-target site resistance (NTSR) in black-grass (Alopecurus myosuroides) and annual rye-grass (Lolium rigidum), poses significant challenges to weed control.
• The phytobiome's role in plant abiotic stress tolerance is increasingly recognized, prompting investigation into microbial endophytes in herbicide-resistant weeds.

Purpose of the Study:

• To investigate the presence of endophytes, specifically viruses, in herbicide-resistant and susceptible populations of black-grass and annual rye-grass.
• To explore the potential link between viral infections and non-target site resistance (NTSR) in these weed species.

Main Methods:

• Transcriptome sequencing of herbicide-resistant and susceptible black-grass and annual rye-grass populations.
• Identification and characterization of viral sequences within the plant transcriptomes.
• Analysis of viral infection incidence in different weed populations, including NTSR-resistant ones.

Main Results:

• Three previously undescribed viruses, AMPV1 and AMPV2 (Partititiviridae) and AMVV1 (Rhabdoviridae), were identified in black-grass populations, with no apparent disease symptoms.
• These viral infections were widespread in UK black-grass and evidence suggested their presence in other grass species like annual rye-grass, perennial rye-grass, and meadow fescue.
• Transcriptome data indicated a high incidence of viral infection in a specific NTSR-resistant black-grass population (Peldon), although a direct causative link to resistance was not established.

Conclusions:

• Widespread, poorly characterized viruses are prevalent in important UK agricultural weeds.
• These persistent viral infections warrant further investigation for their potential role in enhancing plant stress tolerance mechanisms, including non-target site resistance (NTSR).
• Understanding the interplay between viruses and host plants could offer new insights into weed management strategies.