Abstract:

GRAS transcription factors exist extensively in plant genomes and play an important role in both biological and abiotic stress in plants.To study the significant role of the response to stress in soybean cyst nematode (SCN).The susceptible and disease-resistant varieties Dongnong L-10 and Heinong 37 were inoculated with SCN 3 physiological subspecies respectively.After magenta staining was used to confirm the success of insect grafting,transcriptome sequencing was performed on plant roots.A total of 20 candidate genes related to SCN were obtained.The secondary and tertiary structures,phosphorylation sites,hydrophilicity and hydrophobicity,promoter information and gene evolution relationship of encoded proteins were analyzed and studied in bioinformatics.mRNA was extracted from different tissue parts of the plant,including roots,stems and leaves,and reverse transcription cDNA was performed for key candidate genes by RT-PCR.The results showed that the genes in this family were closely related to MYB and MYC transcription factors.The protein encoded by the gene was mainly α-helix and random coil,and the secondary structure and tertiary structure were highly consistent.Protein was a soluble protein,the phosphorylation site was mainly serine.RT-PCR showed that there were certain expression levels in different parts of plant tissues,mainly in roots.The GRAS expression level of resistant cultivars was significantly higher than that of susceptible cultivars under the same soybean cyst nematode stress.GRAS transcription factors were identified as SCN-related resistance genes,providing an important source of genes for resistance to stress response.

Key words: Soybeans, GRAS transcription factors, RT-PCR, Bioinformatics, Soybean cyst nematode