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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #313887
Title: Introgression of resistance-conferring ALS mutations in herbicide-resistant weedy rice

Author
item SINGH, VIJAY - University Of Arkansas
item BURGOS, NILDA - University Of Arkansas
item SINGH, SHILPA - University Of Arkansas
item BASU, SUPRATIM - University Of Arkansas
item Gealy, David
item PEREIRA, ANDY - University Of Arkansas

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/24/2015
Publication Date: 2/1/2015
Citation: Singh, V., Burgos, N.R., Singh, S., Basu, S., Gealy, D.R., Pereira, A. 2015. Introgression of resistance-conferring ALS mutations in herbicide-resistant weedy rice. Proceedings of Southern Weed Science Society. 62:242.

Interpretive Summary:

Technical Abstract: Weedy red rice (Oryza sativa) competes aggressively with rice, reducing yields and grain quality. Clearfield™ rice, a nontransgenic, herbicide-resistant (HR) rice introduced in 2002 to control weedy rice, has resulted in some ALS-resistant weedy rice apparently due to gene flow. Studies were conducted to determine the occurrence and morphology of resistant weedy rice in fields with histories of Clearfield™ rice and persistent infestations of ALS-resistant weedy rice, and to verify the resistance-conferring mutations in the ALS gene. Weedy rice collected from 11 counties in Arkansas, USA, were tested for resistance in a field experiment consisting of 89 weedy rice accessions and 3 Clearfield™ rice cultivars in Stuttgart, AR (2011). Sequential applications of imazethapyr were made at dosages of 0.5x and 1x (0.071 kg ai ha-1), respectively. Injury and mortality were recorded 21 days after the second application. Two-to-five HR plants per accession per replication (727 plants) were identified based on different plant phenotypes and characterized for 14 morphological traits. Allele-specific PCR-based genotyping was used to detect point mutations in the ALS gene, S653N and G654E in resistant plants. The ALS gene of 10 selected HR accessions was sequenced using Automated DNA Sequencing and aligned (Bioedit®) with those of Clearfield™ cultivars to verify the mutation. The S653N mutation, which is one of the mutations in Clearfield™ rice that confers resistance to imidazolinone herbicides, was detected in all of the resistant red rice accessions. Outcrossing between weedy rice and Clearfield™ rice will be verified using genome-wide micro-satellite markers.