Investigating the Phenophysiological Traits of Transgenic Rapeseed Lines (Brassica napus) with aroA Gene Harboring a Point Mutation of Proline 101 to Serine (P101S) under Glyphosate Herbicide Treatment

One of the most effective ways to breed glyphosate-resistant plants is to reduce the affinity of glyphosate to the EPSPS enzyme by manipulating the aroA gene. In this study, P101S mutation was induced in the aroA of E. coli and the mutant gene was cloned in the pUC18 plasmid. It was transferred by Agrobacterium tumefaciens to the rapeseed. To investigate the phenophysiological traits in transgenic rapeseed lines under different glyphosate treatments (0, 1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 76.8 and 153.6 mM), the seeds of T2 generation transgenic plants were studied in greenhouse conditions in a factorial experiment. The results showed that the control (no herbicide) had the lowest amount of days to flowering (32.5 days), partial water pressure (14.92kPa), active photosynthetic radiation (393.4 mmol m−2 s−1), and leaf surface temperature (28.880°C). The concentration of 2.4 mM had the highest stomatal conductance (0.573 mol m−2 s−1) and photosynthesis rate (14.07 μmol m−2 s−1). The lowest value of stomatal resistance was related to the concentration of 4.8 mM (246.9 mmol m−2 s−1), and the lowest value of stomatal conductance was associated with 9.6 mM (0.047 mol m−2 s−1). The highest rate of CO2 source (416.3 ppm) and active photosynthetic radiation (576.9 mmol m−2 s−1) was seen in the 19.2 mM. The 38.4 mM had the highest number of days to flowering (48.1 days) and leaf surface temperature (38.748°C) and the lowest amount of CO2 source (386ppm). The 76.8 mM had the highest stomatal resistance (330.2 mmol m−2 s−1) and the lowest photosynthesis rate (1.36 μmol m−2 s−1). The highest partial pressure of the water source was related to 153.6 mM (19.07 kPa). In summary, different concentrations of herbicides exhibit varying degrees of phenophysiological traits, and desired traits can be improved based on these concentrations.