Characterization and Management of Acetolactate Synthase Inhibiting Herbicide Resistant Mouse-Ear Cress (Arabidopsis thaliana) in Winter Wheat

The first case of field evolved acetolactate synthase (ALS) inhibiting herbicide resistance in the model plant, mouse-ear cress, was reported in winter wheat fields in Westmoreland County, Virginia. A putative resistant (R) mouse-ear population was assessed for ALS resistance relative to a putative susceptible (S) and a susceptible lab population Columbia (C). Results indicated that the R population needed 23 to >2400 fold rate of thifensulfuron relative to S or C population, and it has evolved cross-resistance to sulfonylureas (SU), triazolopyrimidine sulfonanilides (TP), and sulfonylaminocarbonyltriazolinones (SCT). Further studies sequenced the whole genome for four field populations, representing two locations and two resistance levels (high and low) per location, to characterize the genetic mechanism of ALS resistance. The results revealed that all populations contained mutations in the ALS gene at the Pro197 site, although the Pro was substituted by Phe in one location and Thr in the other. Also, both high- and low-level resistant plants at one location had additional mutations (Trp574Leu or Asp376Glu) known to confer resistance to ALS inhibiting herbicides. Patterns of herbicide cross-resistance also varied among the populations. Additionally, research was conducted to assess preemergent (PRE) and postemergent (POST) alternative herbicide options for control of ALS resistant mouse-ear cress and its interference with winter wheat. Results indicate flumioxazin, pyroxasulfone, and metribuzin can be used for effective PRE control whereas 2,4-D, dicamba, and metribuzin can be effective post control options. No mouse-ear cress interference with winter wheat was observed at density of more than 300 plants m-2.

Name thesis:degree_name

Master of Science in Life Sciences

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Plant Pathology, Physiology, and Weed Science

Department dc:contributor.department

Plant Pathology, Physiology, and Weed Science

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2017

Author dc:creator

• Randhawa, Ranjeet Singh

Chair dc:contributor.committeechair

• Flessner, Michael L.

Committee members dc:contributor.committeemember

• Westwood, James H.
• Cahoon, Charles W.

• ALS inhibitors
• differential resistance
• density
• PRE control
• POST control
• target site
• DNA sequencing
• whole genome

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:12741

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/79370