Cloning Of PtrNAC1 Gene From Popolus Trichocarpa And Its Response To Low Nitrogen Environment

In poplars,analysis of transcriptome data has shown that certain genes have contributed to the growth of lateral roots of poplars.We established a genetic network that contains a large proportion of differentially regulated transcription,of which only three are transcription pairs.Root development has a strong influence.Under the condition of low nitrogen,up and down regulation of the three genes respectively causes the increase and decrease of roots.The transcription factor PtrNAC1 is one of them.In this experiment,the bioinformatics analysis of the PtrNAC1 gene was first carried out.It was predicted that the NAC protein of Populus deltoides has a domain in the amino acid sequence 12-137,and this domain is conserved.We cloned the PtrNAC1 gene from the whole genome of Populus yangensis and constructed the plant expression vector pROKII-PtrNAC1.We carried out the genetic transformation of tobacco and 84K poplar respectively and obtained resistant plants respectively.As a material,we conducted low in the nitrogen treatment,0,5 mM NH4Cl,10 mM NH4Cl,5 mM NaNO3,and 10 mM NaNO3 treatment liquids were set,and the chlorophyll content and nitrogen content of the treated wild-type and transgenic lines were measured and physiological and biochemical measurements were performed.The results show:(1)The PtrNAC1 gene has a total length of 918 bp,a number of amino acid residues of 305,a relative molecular mass of 34655.33,an isoelectric point of 6.71,and an acidic,unstable protein and hydrophobic protein.The analysis predicts the presence of a conserved domain NAC.(2)The pROKII-PtrNACl plant expression vector was constructed,the genetic transformation of tobacco and resistance plants were induced by agrobacterium-mediated transformation,and the transgenic plants with high,medium,and low gene expression levels were treated with low-nitrogen and their leaves were treated.Determination of physiological and biochemical indicators(POD?SOD?MDA).The results showed that under low nitrogen treatment,transgenic tobacco was superior to non-transgenic tobacco,and the high expression of L1 was significantly different.(3)Agrobacterium-mediated transformation of 84K poplar was used to obtain resistant plants,and three transgenic lines with high,medium,and low gene expression levels were selected for low-nitrogen treatment.The chlorophyll content of the leaves was measured,and the nitrate nitrogen,ammonium nitrogen and physiological and biochemical indexes of the leaves and roots were determined.The results showed that the contents of chlorophyll,nitrate nitrogen and ammonium nitrogen in transgenic 84K poplars were higher than those in non-transgenic 84K poplars under low nitrogen treatment.Physiological and biochemical measurements showed that transgenic 84K poplars were superior to non-transgenic 84K poplars,with high expression levels.The difference in amount of L1 is significant.