Functional Analysis Of A Stress Resistant Gene ZmDi19-5 From Maize

Corn is the most widely cultivated food and feed crop in the world.Because of its unique economic value,per capita consumption of corn is regarded as one of the main indicator to measure the national standard of living and development of animal husbandry.China has become the largest country in global corn acreage,however,more than 50% of the corn growing areas was subject to severe drought and soil salinization,which caused tremendous lossesto our country's maize production.It has been proved that discovery and taking advantage of novel drought resistance genes in breeding programs is the most sustainable solution to solve abiotic stress.Transcription factor,serving as extremely important molecule switches,enabled plants to withstand unfavorable conditions by involvement in stress signal transduction pathway.Therefore,screening and identification of transcription factor,which was engaged in regulating plant's response under stress,has become a hot topic in crop breeding.Drought-induced 19 protein(Di19)is an important transcription factor closely related to stress tolerance and it is reported to be widely involved in regulating plant responses to stress.Therefore,this type of protein has a greater potential in plant resistance breeding.However,none of Di19 family protein from maize has been characterized.In the present study,we cloned and characterized the function of ZmDi19-5 in an overexpressed transgenic Arabidopsis.In addition,the molecular mechanism of ZmDi19-5 gene involved in stress resistance was preliminarily studied by transcriptome sequencing of the overexpressing transgenic Arabidopsis.The following are main results:1.According to the analysis of amino acid sequence,it was found that maize ZmDi19-5 protein not only contained two highly conserved Cys2/His2 zinc finger proteins,but also contained zf-Di19 and Di19_C domains,indicated that ZmDi19-5 gene belongs to C2H2 transcription factor family.2.Quantitative RT-PCR analysis with various maize tissues revealed thatZmDi19-5 was widely expressed in diverse maize tissues,with the highest expression level in stem.Moreover,ZmDi19-5 gene could beup-regulated after induction of high salt and high concentration of PEG.3.ZmDi19-5 resided on the cell membrane,and no transcription activity could be detected in yeast.4.The heterologous over-expression of ZmDi19-5 in transgenic Arabidopsis thaliana incredibly increased the tolerance of both salt and drought stress.5.Transgenic plants overexpressing ZmDi19-5 exhibited hyposensitivity to ABA treatment in seedling stage.The results indicated that ZmDi19-5was not involved in ABA signaling pathwayduring seeding stage.6.Comparison of transcriptome between transgenic lines and wild type accession identified 22 differentially expressed genes,majority of which was demonstrated to be involved in various stress response pathways.