Abstract Junglerice (Echinochloa colona) is one of the most problematic weed species in rice fields in Colombia. Herbicides inhibitors of the enzyme acetolactate synthase (ALS) have been widely used to control junglerice and other grass species. ALS inhibitors have the highest reports of resistance worldwide, and Colombia has recent reports of ALS resistance in E. colona. The timely and accurate detection of resistance sources is imperative for mitigating and managing herbicide resistance. However, for E. colona there are no published sequences of the ALS gene. In this research, primer design, RNA extraction, cloning, miniprep, and PCR were used to obtain the first partial sequence of the ALS gene on susceptible and resistant accessions of E. colona. The sequences did not present nucleotide differences that could be associated with target-site resistance to ALS inhibitors. Echinochloa (ALS worldwide E However research design extraction cloning miniprep targetsite target site

Abstract RNA interference (RNAi) is a next-generation technology for weed management. Weeds would be sprayed with small RNAs (sRNAs) capable of inducing gene silencing (referred to as spray-induced gene silencing, SIGS) without involving the use of transgenes, reaching traditional targets in chemical control, targets that are not today more sensitive to herbicides and even new targets. Here we present the main challenges and opportunities for using SIGS as a practical tool for weed management. The development of SIGS in weed science has been slower compared to other crop protection areas such as entomology and plant pathology due to the difficulty of obtaining stable molecules that easily enter the plant, without off-target risks to crops, and that in small amounts guarantee systemic silencing with effectiveness. To overcome the challenges, it is necessary to achieve the synthesis of sRNAs on a large scale, making the field application practical and economical, develop formulations that protect sRNAs inside and outside the plant, and substantially increase the genomic and transcriptomic information available for weeds. Once these barriers have been overcome, SIGS technology could be similarly used in the field as herbicides are used today, spraying directly on the crop and selectively controlling weeds. This will provide a new tool for weed management, herbicide resistance management, and potentially exploration of new plant enzyme targets never before achieved by chemical control.