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"Potential use of LIBS and Raman Spectroscopy in confirming non-target site herbicide resistance mechanism in weeds"

Dr's. Vijay Singh and Muthu Bagavathiannan
Soil and Crop Sciences ,Texas A&M University


Herbicide resistance is one of the major problems to weed management, posing great challenges to herbicide sustainability and crop production in world agriculture. Repeated applications of herbicides over several years expose large number of individuals/plants to selection pressure for resistant alleles. Resistant weeds can survive herbicide applications through several physiological mechanisms, which are broadly characterized into target-site and non-target site mechanisms. Target-site resistance mechanisms include increased expression of the target protein or structural changes to the herbicide binding site (gene mutation conferring amino acid change), leading to an uninterrupted production of the target enzyme at sufficient levels. On the other hand, non-target site resistance mechanisms involve altered absorption, translocation, and/or enhanced metabolic detoxification of the herbicides by gene families such as the cytochrome P450 monooxygenases and glutathione S-transferases. Reduced absorption and translocation is an important component in the study of herbicide resistance mechanisms. As a part of these tests, the absorption and translocation of herbicides is routinely investigated using various analytical techniques and complementary approaches to detect localization in plant tissues and organelles. Radioactive herbicides (14 C-labelled) have been typically used for this purpose for over half a century. However, experiments involving radio-active materials are expensive and subject to health and safety issues, thus requiring specialized training. Alternatively, laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy can be studied to differentiate resistant and susceptible plant types with changes in plasma temperature and detecting the herbicide molecules in plant tissues. Applications of these technologies would expedite the research efforts towards the identification of target/ non-target site mechanisms and management of herbicide-resistant weeds in general.

Monday, March 13, 2017
IQSE Seminar Room (578 MPHY), 2:00 p.m.
Mitchell Physics Building

Institute for Quantum Science and Engineering
Texas A&M University

(Coffee and cookies served 15 minutes before start time)