The differential binding and biological efficacy of auxin herbicides     

Justyna Prusinska  Veselina Uzunova  Paul Schmitzer  Monte Weimer  Jared Bell  Richard M. Napier 《Pest management science》2023,79(4):1305-1315

Background

Auxin herbicides have been used for selective weed control for 75 years and they continue to be amongst the most widely used weed control agents globally. The auxin herbicides fall into five chemical classes, with two herbicides not classified, and in all cases it is anticipated that recognition in the plant starts with binding to the Transport Inhibitor Response 1 (TIR1) family of auxin receptors. There is evidence that some classes of auxins act selectively with certain clades of receptors, although a comprehensive structure–activity relationship has not been available.

Results

Using purified receptor proteins to measure binding efficacy we have conducted quantitative structure activity relationship (qSAR) assays using representative members of the three receptor clades in Arabidopsis, TIR1, AFB2 and AFB5. Complementary qSAR data for biological efficacy at the whole-plant level using root growth inhibition and foliar phytotoxicity assays have also been analyzed for each family of auxin herbicides, including for the afb5-1 receptor mutant line.

Conclusions

Comparisons of all these assays highlight differences in receptor selectivity and some systematic differences between results for binding in vitro and activity in vivo. The results could provide insights into weed spectrum differences between the different classes of auxin herbicides, as well as the potential resistance and cross-resistance implications for this herbicide class. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Photosynthetic Response of Maize Plants Against Cadmium and Paraquat Impact   总被引：1，自引：0，他引：1  

Ganka Chaneva  Petya Parvanova  Nikolina Tzvetkova  Alexandra Uzunova 《Water, air, and soil pollution》2010,208(1-4):287-293

The effects of cadmium (Cd) and/or paraquat (PQ) toxicity on photosynthesis in maize leaves were examined by measurement of gas exchange and chlorophyll content in hydroponically cultured plants. It was found that growth rate was distinctly influenced only by 100 µM Cd treatment. Chlorophyll a and chlorophyll b decreased along with the increase of Cd concentration, while PQ spraying, alone and combined with Cd, increased chlorophyll a content on the third and seventh experimental days. Generally, carotenoid content increased in response to Cd and PQ and reached the highest levels at 100 µM Cd. Rate of photosynthesis in maize decreased after Cd treatment. CO₂ assimilation was approximately 60% reduced at 50 µM Cd and 70% reduced in the presence of 100 µM Cd. PQ toxicity was partly overcome after the third day of exposure. Transpiration and stomatal conductance in maize leaves decreased on the third day along with Cd concentration and PQ spraying, except for the 25-µM Cd-treated plants. On the tenth day, the 25-µM Cd-treated plants and those from PQ-treated variants showed an increase of transpiration and stomatal conductance. Maize exhibited an ability to accumulate Cd in high quantities, especially in the roots—over 4,500 mg Cd/kg dry weight.  相似文献   

Abundance, polymorphism and genetic mapping of microsatellites in oilseed rape (Brassica napus L.)   总被引：9，自引：0，他引：9  

M. I. Uzunova  W. Ecke 《Plant Breeding》1999,118(4):323-326

The objective of the present study was to estimate the abundance and degree of polymorphism of simple sequence repeat (SSR) markers in rapeseed. By screening about 45000 clones of a small inserts library of rapeseed total DNA the abundances of GA/TC and CA/TG simple sequence repeats in the rapeseed genome were estimated to be approximately one repeat every 100 kb and 400 kb, respectively. After sequencing 13 positive clones, primer pairs could be designed for 11 microsatellite loci. Seven of these primer pairs produced reproducible amplification products in a set of 31 rapeseed genotypes, with one pair amplifying two independent products, giving a total of eight amplified loci. The different microsatellite loci displayed between one and three visible alleles. At four loci, additional null alleles were observed. With up to four alleles, polymorphic microsatellite markers show significantly higher allele numbers in rapeseed than restriction fragment length polymorphism (RFLP) markers. Four of the eight microsatellite markers could be mapped on four different linkage groups of an RFLP map of the rapeseed genome.  相似文献