| Maize is the main food and economic crop in China.With the aggravation of environmental pollution and the decrease of freshwater resources,the yield of maize has been seriously affected.Therefore,improving crop production environment and cultivating stress-resistant and High-yielding Maize Varieties are effective ways to solve and improve the dilemma of maize production in China.B3 gene superfamily members contain conserved domains that bind to specific DNA motifs in higher plants,and some of them play an important role in plant response to stress and growth and development.As a key gene of B3 gene family,NGAL2 gene in Arabidopsis thaliana has been known to play an important role in the regulation of seed size,but the function of NGAL2 gene in maize has not been reported yet.In this study,the homologous gene ZmNG2059 of NGAL2 in maize was cloned and its potential biological functions were analyzed.The main results and conclusions were as follows:1.Protein domain analysis showed that ZmNG2059 gene contained a conserved B3 domain.Tissue expression pattern analysis showed that the gene was generally expressed at all stages of maize growth,but the highest expression was in roots.Under different abiotic stress treatments,ZmNG2059 could respond to abscisic acid induction,drought,salt ion and heavy metal stress.By constructing the fusion expression vector pMDC43-ZmNG2059-GFP,the results showed that the fusion protein of ZmNG2059-GFP was localized in the nucleus.2.By constructing the ZmNG2059 overexpression vector,the functional deletion mutant of ngal2ngal3 in Arabidopsis thaliana was transformed.The results showed that ZmNG2059 could not replenish the phenotype of large seeds of Arabidopsis thaliana ngal2ngal3 functional deletion mutant,suggesting that ZmNG2059 gene may be different from Arabidopsis NGAL2,and did not participate in the biological process of seed development.3.In response to stress,we treated mutants and replenished plants with NaCl,CdCl2,mannitol and ABA according to the results of induced expression under abiotic stress.The results showed that ZmNG2059 could not respond to salt ion and heavy metal stress.After treatment with NaCl and CdCl2 at different concentrations,there was no difference in phenotype between the replenished plants and the mutant and wild type controls.Under mannitol treatment,the root length of the reinforcing plant was about 21.7%longer than that of the mutant,and the reinforcing plant showed higher sensitivity to ABA than the mutant.ZmNG2059 was overexpressed in wild-type Arabidopsis thaliana.The results showed that the survival rate of overexpressed Arabidopsis thaliana was about 280%higher than that of wild-type Arabidopsis thaliana under real drought.Overexpressed plants showed higher sensitivity to ABA than wild-type plants.These results suggest that ZmNG2059 is a key gene involved in ABA signal regulation of plant drought resistance.4.By analyzing the expression of ABA pathway-related genes,it was found that the expression of ABA pathway and ABA synthesis-related genes(RD22,NCED3,MYB2)in overexpressed plants was significantly higher than that in wild-type plants,but the expression of CBF1 genes independent of ABA pathway was not significantly different.The results showed that ZmNG2059 gene played an important role in ABA signaling network and might enhance plant adaptability to drought stress by relying on ABA signaling pathway. |
