Identification Of Maize Genes Conferring Cadmium Tolerance

Cadmium(Cd)is considered one of the most toxic heavy metal contaminants that can easily be absorbed into the crop plants through the roots,and then migrate in the food chain,not only affect the quality and yield of crops,but also to human health caused great threat.So find metal tolerance genes of plant and elucidate their function has important theoretical and practical significance.In plants,transcription factor that regulation of cadmium detoxification has been a lack of research.Studies have shown that heat shock transcription factor plays an important role in the response to various abiotic stresses.Under salt stress,the arabidopsis plants which overexpressing of HsfA2 is increased resistance,and resistance to osmotic stress also increases.Arabidopsis HsfA3 is proved regulated by DREB2A,a transcription factor involved in dehydration responses.In tomato,inhibit the expression of HsfAla will reduce its resistance to high temperature stress.Corn mitochondria sHsps(msHsp)can improve mitochondrial electron transport chain under salt stress,mainly because of protecting the NADH:ubiquinone oxidoreductase activity.Chloroplast sHsp26.2 has been reported in the heat tolerant creeping bentgrass grass variant.Under heat stress,rice HsfA4d mutant has an allergy to high temperature.In this study,corn library was screened for cadmium-resistant clones by yeast mutant Aycfl,9 clones obtained:The Cd tolerant genes include ZmHsfA5,histone H3,hypothetical protein,oxygen-evolving enhancer protein 2,chloroplastic(OEE2),thyroid adenoma-associated protein homolog(Thada),BTF3 transcription factor,mitochondrial NADH dehydrogenase subunit 2((ND2),uncharacterized protein LOC1003 843 62 iso form X1,and ASR1(ABA-,stress-and fruit-ripening inducable-like protein)?Additionally,the genes,from RNA sequencing results,which induced by cadmium stress built into the yeast expression vector pFL61,yeast heterologous functional complementary technologies identified under the stress of cadmium and other heavy metals patience,yet get Cd gene,but found two genes resistant Nickel:GRMZM2G102786(heavy metal-associated domain containing protein,HMA6,PAA1)and GRMZM2G151406(copper-exporting ATPase,HMA7,RAN1).In tomato and Arabidopsis,HsfA4a and HsfA8 is supposed to act as the sensor of reactive oxygen species(ROS),while HsfA5 is determined to be inhibitor of HsfA4.Thus,in this experiment,cadmium-resistant gene heat shock transcription factor ZmHsfA5 for the study,a preliminary analysis of its function,we not only verify the cadmium tolerance of ZmHsfA5 through yeast heterologous complementation experiments,but also found ZmHsfA5 confer Cu stress.Furthermore,plant genes in heat shock transcription factor A5 family(including OsHsfA5 and AtHsfA5)were screened under the cadmium stress,and the results showed that only ZmHsfA5 confer Cd tolerance.After fusing ZmHsfA5 to the YFP in the vector pXZP008,the laser confocal microscopy result showed that ZmHsfA5 localized in the nucleus.