| Conyza canadensis,is a malignant weed in drylands in China,which has a great impact on the yield of agricultural crops such as autumn crops.The use of chemical herbicides has increased the resistance of weeds.In order to develop plant-derived herbicides,in this study,the C.canadensis was used as the experimental material,and explores the allelopathy and herbicidal mechanism of octanoic acid to the C.canadensis.The following results were obtained: 1.Based on the proteomics data information of C.canadensis which treated by octanoic acid,the complete c DNA sequence encoding Cc Lhca-Z6 gene was cloned by homologous cloning and RACE technology,and the relative expression level of Cc Lhca-Z6 were compared by RT-q PCR in different times after octanoic acid treatment.The results show that the full length of the Cc Lhca-Z6 gene sequence is 1,016 bp(Gene Bank sequence number is MH512007.1),which encodes 266 amino acids,has a molecular weight of 28.14 k Da,and the theoretical isoelectric point of this protein is 5.29.The Cc Lhca-Z6 protein is the closest with the Lhca-Z6 of Artemisia annua L.(PWA84283.1)in protein evolution level,and they are closer in the same branch.The results of RT-q PCR analysis showed that the treatment with octanoic acid significantly affected the expression of Cc Lhca-Z6 gene in leaves of C.canadensis,and showed a trend of first rise and then decrease with time.When the treatment time was 2 h,the relative expression of Cc Lhca-Z6 gene reached the maximum value,which was 20.6 times that of the control group.This result is similar to the previous proteomics results.It was speculated that the Cc Lhca-Z6 gene may be the key gene of C.canadensis in response to octanoic acid stress.The results of this study lay the foundation for further exploring the action mechanism of plant-derived herbicide octanoic acid.2.The plantserine hydroxymethyl transferase(SHMT)activity octanoic acid at different times.The results showed that with the increase of the processing time of octanoic acid,the enzyme activity of SHMT slowly increased first,reached the highest value at the treatment time of 2 h,and then slowly decreased.It is guessed that C.canadensis had withered at 24 h.3.Using the leaves of the C.canadensis as the experimental material,induce the formation of callus and establish the regeneration system of the C.canadensis,and then use the Agrobacterium-mediated method to transiently express the GUS gene in the callus of the C.canadensis.The results showed that: under the condition of 0.5 mg/L 6-BA+0.5 mg/L NAA+MS medium,the leaves of C.canadensis had the best effect on inducing callus and cluster buds.Under the basic conditions,it can successfully induce cluster budding and root regeneration.The Agrobacterium-mediated method was used to introduce the GUS gene into the callus of C.canadensis.After GUS staining,it was proved that the GUS gene can be transiently expressed in the induced callus.In summary,our research shows that the treatment with octanoic acid can indeed cause a series of physiological and biochemical reactions in C.canadensis.,which has the potential for development as a safe and efficient biologically-derived herbicide,and Cc Lhca-Z6 may be the key regulatory gene.It provides a theoretical basis for the development of octanoic acid as a biologically-derived herbicide. |
